Service Handbook
Residential FVIR Gas Water Heaters
MODELS: GSN, GTN, GSL, GTL- Series 300/301
LOW LEAD CONTENT
THIS SERVICE HANDBOOK IS FOR USE BY QUALIFIED SERVICE PROFESSIONALS ONLY. 100324809 2000580429 (Rev. A) October 2019 TABLE OF CONTENTS
General Safety...... 4 Completed Installation (typical)...... 6 System Basics...... 7 Honeywell® Gas Control Valve/Thermostat...... 7 Gas Pressures...... 7 BASICS BASICS Temperature Settings...... 7 Combustion Chamber with TCO Switch...... 8 Lighting the Pilot / Diagnostic Flash Codes...... 9 Lighting the Pilot: ...... 9 If the Status Light Does Not Blink:...... 9 If the Pilot Does Not Light:...... 9 If the Pilot Lights but the Status Light Does Not Blink:...... 9 Diagnostic Flash Codes...... 10 0 Flashes (LED not lit) ...... 10 Status Light On (solid) ...... 10 1 Flash ...... 10 2 Flashes ...... 10 4 Flashes ...... 10 5 Flashes ...... 10 7 Flashes ...... 10 8 Flashes ...... 10 System Checks...... 11 Draft Test ...... 11 Connections Check...... 11 Gas Pressure Checks...... 11 Thermopile Check (Open Circuit)...... 12 Thermopile Check (Closed Circuit)...... 12 Common Issues...... 13 No Hot Water...... 13 Not Enough Hot Water...... 13 Lower Seasonal Water Temperatures...... 13 Faulty Shower Control Valve/Faucet Valve...... 14 Thermostat Set Too Low...... 14 An Increase in Hot Water Usage...... 14 Undersized Water Heater...... 14 Reversed Water Connections...... 14 Leak in the Plumbing System ...... 14 Sediment Buildup in the Tank...... 14
2 • Residential Standard Gas Water Heater Service Handbook Tank Leak...... 15 Condensation...... 15 Leaking Plumbing Connections...... 15 Drips from the T&P Relief Valve Discharge Pipe...... 15 Temperature Too High...... 16
Low Water Pressure...... 16 BASICS BASICS Water Odor...... 16 Service Procedures...... 17 Removing the Manifold/Burner Assembly...... 17 Removing the Burner from the Manifold/Burner Assembly...... 17 Replacing the Pilot/Thermopile Assembly...... 17 External Inspection and Cleaning of the Base-Ring Filter...... 18 Cleaning the Combustion Chamber and Flame Arrestor...... 18 Replacing the Manifold/Burner Assembly...... 19 Testing the Igniter System...... 19 Removing and Replacing the Gas Control Valve/Thermostat...... 20 Removing the Gas Control Valve/Thermostat:...... 20 Replacing the Gas Control Valve/Thermostat:...... 20 Draining and Flushing...... 20 Supplements...... 21 Evaluating Combustion and Ventilation Air Supply...... 21 Attic Installations ...... 23 Overview...... 23 Pilot Outage...... 23 Elevated Air Temperature:...... 24 Insufficient Makeup Air...... 24 Blocked Air Screen or Flame Arrestor...... 24 Improper Venting of the Water Heater...... 24 Decompression ...... 25 Wind ...... 25 Water Damage...... 25 Elevated Water Temperature...... 25 Field Installation of Draft Hoods ...... 26 Tools and Materials...... 26 Types of Draft Hoods Covered in this Section...... 26 Types of Vent Pipe Covered in this Section...... 27 Installation Procedure...... 27 Coupling...... 27 Type B Draft Hood Connectors...... 28
Residential Standard Gas Water Heater Service Handbook • 3 GENERAL SAFETY
Your safety and the safety of others is extremely important in the servicing of this water heater. Many safety-related messages and instructions have been provided in this handbook and on your water heater to warn you and others of a potential hazard. Read and obey all safety messages and instructions throughout this handbook as well as those found in the Installation Instructions/ Use & Care Guide. It is very important that the meaning of each safety message is understood by you and others who service this water heater. The information contained in this handbook is designed to answer commonly faced situations encountered in the operation of the standard Residential Gas product line and is not meant to be all-inclusive. If you are experiencing a problem not covered in BASICS BASICS this handbook, please contact the Technical Information Center listed on the back cover of this handbook for further assistance. Additional information is also available on the web site listed on the back cover of this handbook. This handbook is intended for use by licensed plumbing professionals and reference should be made to the Installation Instructions and Use & Care Guide accompanying the product. This handbook contains supplemental information to the Installation Instructions and Use & Care Guide. When servicing residential water heaters, it is essential that you return the unit to a safe condition before you leave the site. All original components must be re-installed and all safety measures must be implemented. In addition, the recommended water temperature setting is 120° F. IMPORTANT: It is recommended that on every service call, an inspection & cleaning of the base ring filter and flame arrestor be performed. See page 18. Tools Required (for servicing gas models): • Phillips head screw driver • 3/8, 7/16, & 3/4 inch open end wrenches • 3/16 inch Allen wrench • 1-1/16 inch – 6 point – socket – for anode removal • Electrical multimeter (with alligator leads) • Digital or analog manometer ON • Gas pressure gauge • Water pressure gauge • Thermometer • Hose – to drain tank • Container – to measure gallons per minute flow Digital Manometer
4 • Residential Standard Gas Water Heater Service Handbook BASICS BASICS
Fire or Explosion Harzard
Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance. Avoid all ignition sources if you smell Natural or LP gas. Do not expose water heater control to excessive gas pressure. Use only gas shown on rating plate. Maintain required clearances to combustibles. Keep ignition sources away from faucets after extended period of non-use.
Read instruction manual before installing, using or servicing water heater.
Fire or Explosion Harzard Hydrogen gas can be produced in a hot water system after a period of non-use (generally two or more weeks). Hydrogen gas is extremely flammable and can ignite. To return hot water system to service, open a hot water faucet in kitchen for several minutes before using electrical appliances. Do not smoke or have open flame near faucet while it is open. Leave hot water faucet open until the sound of escaping air stops.
After extended period of non-use, purge gases from hot water system.
Residential Standard Gas Water Heater Service Handbook • 5 COMPLETED INSTALLATION (TYPICAL)
Wa er Suppl Col Wa er E aus Ven o S u O Ousi e o Buil ing See La els an Val e Ins alla ion Ins ru ions an Use Care Gui e Massa use Ins all BASICS BASICS or learan es. Union a a uu relie in ol a er line per se ion MGL 2. Union E pansion Tan Pressuri e o E ual Suppl Wa er Pressure Relie e a er pressure To Fi ures Ho on e e pansion an e ore a us ing air pressure. Te pere Wa er To Fi ures Un e pere Gas Suppl Te pera ure Pressure Relie Val e Ho Wa er Col i is arge pipe o an Wa er a e ua e rain. Do no ap or plug. Inle
Manual Gas S u o Val e
Ho Wa er Gas Con rol Val e T er os a Ou le Re o en e se ing o 2 F.
Mi ing Val e Se o 2 F Do no ap or plug. Follo e Mi ing Val e Manu a urer s Ins ru ions
Ma i u Air Gap NOTE Lo al o es Union a ar . Se i en Trap Mini u . Drain Me al Drain Pan pipe o an a e ua e rain. Base Ring Fil er NOTE Drain pan ia e er us e a leas Air is ra n in or o us ion. eep area lean 2 in es i er an e ia e er o e an ree ro la a les an la a le apors. a er ea er.
T e a er ea er us e ins alle a or ing o all lo al an s a e o es or in e a sen e o lo al an s a e o es e Na ional Fuel Gas Co e ANSI 22 . NFPA urren e i ion.
NOTE I on a ell s s e e e pansion an s oul e se o e a i u pressure o e pu p an .
Figure 1.
6 • Residential Standard Gas Water Heater Service Handbook SYSTEM BASICS
Honeywell® Gas Control error codes, see “Lighting the Pilot / The gas control valve\thermostat also Diagnostic Flash Codes” on page 9. includes a temperature limiting ECO Valve/Thermostat (Energy Cut Off) system. This system Water heaters covered by this handbook Pilot flame heats thermopile, will shut off the water heater if the enabling gas control valve/ water temperature becomes excessive. are equipped with Honeywell gas thermostat operation. control valve/thermostats. Should the water temperature get too high, the main burner and pilot • The Honeywell valve uses a Pilot will shut off automatically. Once the BASICS thermopile instead of a thermocouple pilot is relit, the status light will flash as did previous designs. Thermopile a code (4 flashes), indicating an over- • Heat on the thermopile generates temperature condition. See “Lighting 750 to 900 millivolts (open circuit). the Pilot / Diagnostic Flash Codes” on • When heated by the pilot and page 9 for more information. connected to the Honeywell control, NOTE: Honeywell is a registered trademark the thermopile generates at least of Honeywell International, Inc. 350 millivolts (closed circuit). This voltage opens the power head Temperature Settings Figure 2. in the control, allowing gas to The water temperature setting can be flow. It also powers the onboard Gas Pressures adjusted from 55°F to 155°F. Simply diagnostics (status light). See turn the gas control/temperature Knob Figure 2. Ensure that the following pressures are to the desired setting/temperature. • The Honeywell valve uses a standard observed and maintained: See Figure 3. push-button piezo igniter. See “Spark Table 1. GAS PRESSURES NOTE: The temperatures indicated are Igniter” in Figure 2B. approximates. The actual temperature GAS MAXIMUM MANIFOLD • Status codes are printed on the face of the heated water may vary. SUPPLY GAS of the control for easy reference PRESSURE PRESSURE (Figure 2B.) • The LED status light shows the NAT 14 InWC 5.0 InWC current status of the control as well (± 0.4 InWC) as possible error codes for easy LP 14 InWC 10.0 InWC diagnosis. For more information on (± 0.5 InWC) Min. Supply Pressure: See Rating Plate.
Figure 2B
C • 55°F - 155°F with VAC setting • 91°F - 155°F without VAC setting
S include a VAC (vacation) setting.
Residential Standard Gas Water Heater Service Handbook • 7 Scalding Risk • The water heater and/or pipes is located in the center of the switch, A water heater are located in an area with high directly between the terminals. ambient temperatures (e.g., an can make water IMPORTANT: If the thermal switch has attic). See also “Attic Installations” hot enough to been tripped, determine the cause on page 23. cause severe burns and correct it before returning the instantly, resulting in severe injury or • Certain usage patterns, such as water heater to service. Ensure that death. Higher temperatures increase short hot water draws or no hot there are no flammable vapors BASICS the risk of scalding, but even at 120°F, water use for long periods of present. However, a tripped thermal hot water can scald. See Table 2. time, can cause the tank water switch is most likely caused by poor Thermostatic mixing valves at each temperature to rise higher than the combustion (e.g., blocked vent or dirty point of use reduce the risk of scalding. thermostat setting. Modern water filter/arrestor). heaters are very well insulated THERMAL SWITCH (TCO) LOCATION HONEYWELL® GAS CONTROL VALVE/THERMOSTAT and retain heat so efficiently that, under certain circumstances, GAS CONTROL/TEMPERATURE KNOB ≈150°F ≈155°F the tank water temperature can ≈140°F ≈130°F increase over time, particularly 120°F MARK when hot water is not being used. This “heating” effect can be caused VAC
STATUS by the pilot flame itself. LIGHT IGNITER ≈55°F Combustion Chamber TEMPERATURES SHOWN ARE APPROXIMATES AND MAY VARY. SOME MODELS ARE CERTIFIED FOR 180°F. SEE RATING PLATE. with TCO Switch Figure 3. Combustion air is drawn through the base-ring filter and flame arrestor and into the combustion chamber. (See THERMAL Table 2. SWITCH Figure 5.) Sufficient combustion air is (TCO) Water Time to Produce critical to the operation of the water Temperature a Serious Burn heater. 120°F (49°C) More than 5 minutes IMPORTANT: The flame arrestor 125°F (52°C) 1½ to 2 minutes and filter should be inspected and cleaned during each service call. See 130°F (54°C) About 30 seconds page 18 for instructions. Figure 4. 135°F (57°C) About 10 seconds Also, each water heater covered by 140°F (60°C) Less than 5 seconds this handbook is equipped with a resettable TCO switch (thermal switch), FLAME ARRESTOR COMBUSTION CHAMBER 145°F (63°C) Less than 3 seconds designed to shut off the gas supply in 150°F (66°C) About 1½ seconds the event that the water heater has been exposed to high combustion 155°F (68°C) About 1 second chamber temperatures caused by one of the following events: IMPORTANT: Water temperature • Flammable vapors (e.g., spilled in the tank can be higher than the BASE RING gasoline) FILTER thermostat setting. Some of the reasons are: • Poor combustion caused by a Figure 5. • Incoming water temperature is blocked vent higher than the set point (e.g., • Insufficient combustion air. solar-heated water). A resettable thermal switch is illustrated in Figure 4. Its reset button
8 • Residential Standard Gas Water Heater Service Handbook LIGHTING THE PILOT / DIAGNOSTIC FLASH CODES
Lighting the Pilot: door. The control knob must be set may be needed to completely fill the to Pilot and held in continuously line with gas and successfully light 1. Read and follow the lighting while clicking the igniter button the pilot. instructions on the water heater’s (about once per second for up to label. 90 seconds). To observe the Pilot, GAS CONTROL VALVE/THERMOSTAT 2. Turn the control knob to “Pilot.” remove the outer door and look THERMOPILE GAS CONTROL/ WIRE CONNECTIONS Press the knob in fully and hold it in. through the view port (sight glass). TEMPERATURE KNOB VAC (The knob will travel in about 1/4- See Figure 7. PIEZO IGNITER BUTTON inch if it is set to Pilot correctly.) 3. Continue clicking the Igniter button VIEWPORT THERMAL (for up to 90 seconds) until pilot SWITCH 3. While holding the control knob in, OUTER DOOR (TCO) click the igniter button continuously lights. NOT SHOWN for up to 90 seconds or until the 4. Once the pilot is lit, continue to hold Status Light begins to blink. the control knob in until the Status Figure 7. If the status light does not begin Light begins to blink. to blink after 90 seconds, STOP. 5. Release control Knob and set Knob to Release the control knob. Wait desired temperature setting. (“Hot” If the Pilot Lights but the 10 minutes before attempting to is approximately 120°F.) relight the Pilot. Repeat these steps Status Light Does Not 6. Replace the outer door. 2-3 times, if necessary. Blink: CODES PILOT/FLASH The circuitry in this gas valve 1. If the pilot lights, continue to hold the requires that you wait 10 minutes If the Pilot Does Not control knob in until the status light between lighting attempts. Light: blinks. If the pilot is lit and remains If the Status Light blinks, release 1. Wait 10 minutes before another lit for 90 seconds and the Status Light the gas control/temperature knob lighting attempt. If the pilot does not still does not blink, the thermopile and turn it to the desired setting. light, the Igniter may not be sparking connections may be loose, the (“Hot” is approximately 120°F). or the unit may not be getting gas (or thermal switch may need to be reset, or the thermopile may be defective. Gas Control/Temperature Knob for a new installation, there may still be air in the gas line). Each time you 2. Remove the outer door. click the igniter button, you should 3. Press the reset button on the thermal be able to see the spark by looking switch (TCO switch). See Figure 7. through the view port. See Figure 7. (You may have to darken the room 4. If the switch clicks, it may have lights to see the spark.) You do not tripped. Do not light the pilot if have to push the Control Knob in flammable vapors are present. to check the Igniter button. Simply Check flame arrestor for signs of discoloration (which could be Igniter Button look through the sight glass while clicking the Igniter button and look caused by flammable vapors). If the Figure 6. for a spark. If you can’t see a spark flame arrestor is discolored, do not when the Igniter button is clicked, attempt to relight the Pilot. Have the check the wiring connections from water heater inspected by a qualified If the Status Light Does the Igniter button and make sure service technician. Not Blink: that they are tight. 5. Check the wiring connections 2. If you see the igniter spark, try from the thermopile and thermal 1. Wait 10 minutes before another relighting the pilot by following the switch (TCO) to the gas control lighting attempt. instructions on the water heater’s valve/thermostat. Ensure that 2. If the status light did not blink, repeat label. Ensure that the gas supply is all wiring connections are tight. the lighting procedure by following turned on. There may be air in the See Figure 7. the lighting instructions on the water gas line, and several lighting attempts 6. Replace the outer door. heater’s label. Remove the outer
Residential Standard Gas Water Heater Service Handbook • 9 7. Wait 10 minutes and try to light the the Igniter System” (p. 19); 4 Flashes Pilot according to the instructions “Gas Pressure Checks” (p. 11). Indication/Condition: on the water heater’s label. Also, check the thermopile wiring Temperature exceeded (ECO activated). 8. While clicking the igniter button connections (Figure 16, p. 17). continuously, the control knob must Check/Repair: be set to Pilot and held in until the Status Light On (solid) 1. Turn gas control valve/thermostat Status Light blinks. Once the status Indication/Condition: knob to OFF. light blinks, release the control knob Pilot light was recently extinguished 2. Turn the main gas supply OFF. and set the knob to the desired and the thermopile is cooling down. temperature setting. (“Hot” is 3. Replace the gas control valve/ approximately 120°F.) Check/Repair: thermostat. 1. Turn the gas control valve/ Diagnostic Flash Codes thermostat knob to OFF. 5 Flashes 2. Wait 10 minutes for the thermopile Indication/Condition: Sensor failure. NOTE: In each case, the flash code will to cool, then attempt to relight Check/Repair: occur, followed by a 3 second pause, the pilot by following the lighting and then will repeat. instructions on the water heater’s 1. Turn gas control valve/thermostat label. NOTE: This gas control valve/ knob to OFF. PILOT/FLASH CODES PILOT/FLASH 0 Flashes (LED not lit) thermostat has built-in circuitry 2. Turn the main gas supply OFF. that requires waiting 10 minutes Indication/Condition: 3. Replace the gas control valve/ between lighting attempts. Control Off/Pilot Out. thermostat. Check/Repair: Until the Thermopile reaches its normal operating temperature, 7 Flashes 1. Follow the lighting instructions on the the status light will not blink, even front of the water heater and attempt if the pilot is lit. It may take up to Indication/Condition: to relight the pilot. Confirm that 90 seconds of continuous pilot Internal control failure. the pilot is lit by looking through the operation before the thermopile Check/Repair: viewport (Figure 16, p. 17). reaches normal operating 1. Turn gas control valve/thermostat 2. If pilot will light but does not temperature and the Status Light knob to OFF. hold, check for a tripped thermal starts to blink. switch. (Measure continuity by 2. Turn the main gas supply OFF. placing a meter lead on each of 1 Flash 3. Replace the gas control valve/ the two terminals. Continuity Indication/Condition: thermostat. means that it was not tripped.) If Normal Operation (bright/dim thermal switch is tripped, check for heartbeat) 8 Flashes flammable vapors in the area and ensure that the unit has adequate Check/Repair: No corrective action Indication/Condition: Power off failure. combustion air and proper draft necessary. Check/Repair: before relighting. (You can reset the thermal switch by pressing the 2 Flashes 1. If the pilot flame is present when reset button in its center.) Also, the control knob is set to the OFF Indication/Condition: ensure that the filter and flame position, replace the gas control Thermopile voltage low. arrestor are clean (p. 18). valve/thermostat. 3. If the pilot will light and does hold, Check/Repair: 2. If the pilot flame is not present when record any status codes and follow 1. Check all wiring connections for loose the control knob is set to the OFF the procedures relating to that code. or damaged wires. Correct if needed. position, wait 10 minutes for the thermopile to cool, then relight the 4. If pilot will not light at all, verify the 2. Check the millivolt output on the unit. If this condition returns, replace piezo igniter is producing a spark thermopile. If output is less than 350 the gas control valve/thermostat. and the unit is getting the correct millivolts DC, replace the thermopile. supply gas pressure. See “Testing See also “Condensation” on page 15.
10 • Residential Standard Gas Water Heater Service Handbook SYSTEM CHECKS
Connections Check • Supply gas pressure checks are measured before the gas control Some issues can be caused by faulty valve/thermostat and as close Explosion Risk connections. Refer to the following list to the water heater as possible. WARNING! Before performing any of connections when troubleshooting NOTE: The dynamic gas pressure test, check the area around the water the system: (burner on) should be measured heater for any source of a flammable • Igniter wire (Figure 9). See also with all appliances operating that vapor (i.e gasoline, paint thinners, “Testing the Igniter System” on use the common gas supply. etc.). If any sources are found, do not page 19. • Manifold (main burner) gas proceed until they are removed. • Thermopile/thermal switch wires pressure is measured at the at the gas control valve/thermostat pressure tap on the bottom of Draft Test (Figure 9). the gas control valve/thermostat. See Figure 9 and Figure 11. Use a WARNING! Burn Hazard. Do not • Wire connections at the thermal switch (TCO). A disconnected 3/16” Allen wrench to remove the touch the vent. Doing so can cause pressure tap plug, then attach the burns. thermal switch wire can cause the pilot to become inoperable. See gas gauge. After successfully lighting the water Figure 4, page 8. NOTE: Gas outlet pressures will be listed heater, allow the main burner to on the gas control valve/thermostat’s operate for five minutes. Close all See also “Diagnostic Flash Codes” on page 10. pressure label. See Figure 10. Also, windows and doors and turn on all gas supply pressure requirements are gas appliances and air-moving devices shown on the water heater labeling. (range hoods, bathroom exhaust fans, From Thermopile (White) ceiling fans, etc.) in the home. Also, From Thermal Switch (Red) close any fireplace dampers. S ESS E E T ET ESS E
S CHECKS SYSTEM After five minutes, pass a newly ESS E extinguished match about one inch (1”) E from the draft hood’s relief opening. VAC C ECTE T Smoke from the match should be steadily ESS E T drawn into the opening, indicating proper draft and a functioning vent system. DRAFT HOOD M S ESS E TEST RELIEF MATCH OPENING Figure 10.
Igniter Wire Manifold Pressure Tap (1/8” NPT-RH)
Figure 8. Manifold Flex Tube Nut: • Propane: Left-hand threads
If the main burner has been operating • Natural: Right-hand threads for five minutes, but the match smoke Figure 9. drifts around or is blown away from the opening, turn the gas control knob OFF. Do not operate the water heater Gas Pressure Checks until proper adjustments or repairs are Gas pressure checks are made with made to the vent pipe system and/or air CONNECTED AT PRESSURE TAP supply (p. 21). Always check the filter flowing gas. Use a gas pressure gauge and flame arrestor first and clean them, capable of reading pressure in inches if necessary (p. 18). of water column. Figure 11.
Residential Standard Gas Water Heater Service Handbook • 11 2. Insert multimeter leads into the Table 3. Thermopile Check connectors. The multimeter must be set to read millivolts DC (on a (Closed Circuit) Gas Pressures scale that can read 750 millivolts). Follow the lighting instructions to light Reference Figure 12. the pilot. Once the pilot is lit, you can IF . . . check the output of the thermopile with one of the following tests. A . . . THEN reading above 350 mV DC indicates ...the supply gas • increase the that the thermopile is working pressure is lower supply gas properly. than required... pressure regulator setting INSERT MULTIMETER LEADS INTO THERMOPILE PLUGS AT CONTROL. and/or PILOT MUST BE LIT. • increase supply gas piping size.
...the supply • add a gas pressure gas pressure regulator. is higher than • reduce the setting required... USE A MULTIMETER TO CHECK THE OUTPUT OF on the existing THE THERMOPILE (MEASURED IN MILLIVOLTS). regulator. SHOWN ABOVE - MULTIMETER PROBES ARE INSERTED INTO THE THERMOPILE PLUGS. THESE PLUGS WERE REMOVED FROM THE RECEPTACLE AT ...the manifold • ensure that there THE BOTTOM, RIGHT-HAND CORNER OF THE GAS gas pressure is adequate supply CONTROL VALVE/ THERMOSTAT.
SYSTEM CHECKS SYSTEM is not within gas pressure +/- 10% of the Figure 12. MULTIMETER SET TO READ mV. • ensure that the value shown main burner MINIMUM ACCEPTABLE on the gas 3. Follow the lighting instructions to orifice is the MEASUREMENT: 350 mV DC. pressure label... light the pilot. Once the pilot is lit, correct size for the model being continue to hold the gas control Figure 13. tested. knob in until this test is complete. NOTE: The gas INSERT ONE MULTIMETER LEAD INTO pressure label • if the above You may need assistance from THE NEGATIVE PLUG ON THE CONTROL lists the gas tests have been another person to do this. The (WHITE WIRE). valve outlet performed and voltage reading should rise TOUCH THE OTHER LEAD TO A pressure. This the results were TERMINAL ON THE THERMAL gradually as the thermopile heats SWITCH (TCO). is the same as correct, replace up. After a few minutes, you should the manifold the gas control have a reading of at least 350 mV pressure. See valve (p. 20). Figure 10. DC. A reading above 350 mV DC indicates that the thermopile is working properly. Thermopile Check 4. When you are finished, plug the (Open Circuit) connectors back into the gas The following test will check the DC control valve/thermostat. If the voltage generated by the thermopile connectors are separate (not a when the pilot light is lit. double connector), ensure that the red wire connector is to the left and MULTIMETER SET TO READ mV. 1. Remove the connectors from the the white wire connector is to the PILOT MUST BE LIT. gas control valve/thermostat (red MINIMUM ACCEPTABLE right. See Figure 2B, page 7. If MEASUREMENT: 350 mV DC. and white wires). Use needle-nose the status light does not blink once pliers. every three seconds, replace the Figure 14. gas control valve/thermostat.
12 • Residential Standard Gas Water Service Handbook COMMON ISSUES
Fire and Explosion Hazard 8 Flashes replaced). The most likely cause Power Off Failure is contamination in the pilot WARNING! Do not Often, this error can be cleared tube. attempt to light the water by turning the pilot off, letting A. If the pilot is lit and the status heater if flammable vapors or liquids it cool down for ten minutes, light is flashing, refer to are present. Do not store or use then relighting it according to “Diagnostic Flash Codes” on gasoline or other flammable vapors the lighting instructions. See page 10. and liquids in the vicinity of this or any “8 Flashes” on page 10. B. If the pilot is lit, but the status other gas appliance. Storage of or use light did not start flashing, check of gasoline or other flammable vapors 2. If the status light is not lit, see the thermopile (p. 12). If its or liquids in the vicinity of this or any “0 Flashes (LED not lit),” page 10. output is 350 mV or less, it must other appliance can result in serious That section will help you investigate be replaced. If its output is injury or death. causes related to the thermal switch greater than 350 mV, replace the (TCO), spark ignition, gas pressures, gas control valve/thermostat. No Hot Water and thermopile connections. If water is not being heated, check the NOTE: The pilot must be lit for Not Enough Hot Water following: the status light (LED) to flash. Check the following if the water is not Heat from the pilot causes the 1. Look at the gas control valve/ hot enough or if the hot water runs out thermopile to generate voltage. too quickly: thermostat. Is it flashing? If so, Without this voltage, the gas control solutions for restoring hot water are valve/thermostat cannot operate. Possible causes listed below. See also “Diagnostic Remember: it may take up to 90 • Lower seasonal water temperatures Flash Codes” on page 10. seconds to heat the thermopile • Faulty shower control or faucet 1 Flash enough to power the status light. valve Normal Operation • Thermostat is set too low (This code may occur after you 3. If you completed step 2 and • Increased hot water usage relight the pilot.) the pilot will not light, check for • Water heater is too small to meet Once the water heater has air in the gas line. (This is fairly demand completed a heating cycle, it should common with recent work/new provide an adequate amount of installations.) If there is air in • Reversed plumbing connections hot water. If it does not, see “Not the gas line, bleed the line as • Plumbing system leak Enough Hot Water.” If the pilot necessary. Make sure to hold the
• Sediment buildup in the tank ISSUES COMMON lights for a while, then goes out, see gas control knob in fully and hold it “0 Flashes (LED not lit)” on page 10. in. In most cases, energy efficient Verify the water temperature at pilot orifices are so small that it the temperature/pressure relief 2 Flashes valve. Check the mixing valve/ Thermopile voltage is low may be difficult to clear the air by holding the knob in. shower control settings. Also Possible causes/solutions: check for leaks, heavy usage, and • Thermopile is getting weak. When you are finished, try to light extremely cold incoming water. • Check wiring and connections. the pilot. (Follow the lighting In all cases, clean the filter and • If necessary, replace the instructions on the water heater.) flame arrestor (p. 18), then thermopile. See “Replacing Remember to hold the control conduct a draft test (p. 11). the Pilot/Thermopile knob in for at least 90 seconds so A description of each cause and its Assembly” on page 17. the pilot can heat up. solution(s) is listed below. 4, 5, or 7 Flashes Did the pilot light? If it did, check If you observe one of these the following: Lower Seasonal Water Temperatures flash codes, refer to “Diagnostic A. If the pilot did not light, replace In some areas, water coming into the Flash Codes” on page 10. the pilot. (The entire pilot/ tank is much colder during winter thermopile assembly must be
Residential Standard Gas Water Heater Service Handbook • 13 and early spring months. Even when to adjust the thermostat. If there Reversed Water Connections the water heater is working properly, still isn’t enough hot water, set the If the hot and cold water connections it may take longer to fully heat the thermostat to a higher setting and are reversed, it may appear as if the water. As a result, hot water may not install a thermostatic mixing valve at water heater isn’t producing much be available as quickly as it is during each point of use. hot water. This problem is usually warmer months. identified at the time of installation. An Increase in Hot Water Usage Confirm that the home’s hot water Faulty Shower Control Valve/Faucet If hot water is running out during Valve pipe is connected to the water heater’s holidays, weekends, or family hot water outlet, not the cold water Check the hot water at all faucets in gatherings, the demand for hot inlet. If the connections are reversed, the home. Some may have built-in water may be exceeding the water switch them to the correct position. thermostat or pressure-balance mixing heater’s capacity. Hot water usage valves that may need adjustment or can be reduced by washing clothes in NOTE: The water heater’s hot water replacement. If you get hot water from cold water, installing flow restrictors outlet will be marked with an “H” or some outlets but not others, adjust/ on shower heads, and taking other “HOT,” or will be color coded red. replace each fixture as necessary. conservation steps. NOTE: A mixing valve issue is not a Leak in the Plumbing System water heater defect and is not covered Undersized Water Heater A leak in the home’s plumbing system by the water heater warranty. If water is frequently too cool, the can overload the water heater’s ability water heater may be too small. If to heat water. In that case, the water Thermostat Set Too Low the water heater is old, the best heater can be working, but there will solution may be to replace it with a be little or no hot water. Check the Scalding Risk larger model. If the water heater is plumbing system for leaks and repair A water heater can in good condition, you may set the as necessary. make water hot thermostat to a temperature above enough to cause 120°F and install thermostatic mixing Sediment Buildup in the Tank severe burns instantly, resulting valves at each point of use. Set each If the water heater is several years old in severe injury or death. Higher thermostatic mixing valve’s delivery and/or is installed in an area known for temperatures increase the risk of temperature to 120°F to reduce the hard water, there may be a buildup of scalding, but even at 120°F, hot water risk of scalding. (See “Temperature sediment at the bottom of the tank. can scald. See Table 2 on page 8 Settings” on page 7.) Sediment buildup may reduce the before proceeding. Thermostatic This method can increase the effective efficiency of the water heater and may reduce the amount of available hot
COMMON ISSUES COMMON mixing valves at each point of size of the water heater by about 30%. use reduce the risk of scalding. water. If you’ve checked all of the faucets Drain and flush the tank (page 20). and shower controls and the water You may also treat the tank with a temperature is still too cool, the water lime/scale removal solution that is heater’s thermostat may be set too approved for potable water heaters. low. See “Temperature Settings” on page 7 for instructions on how
14 • Residential Standard Gas Water Service Handbook Tank Leak condensation regularly. In that case, a • Water pressure too high. High water larger water heater is recommended. pressure can cause the T&P relief valve to drip. Install a pressure Condensation NOTE: Condensation may cause a “2 reducing valve (PRV) on the main Flashes” error code, indicating low If you see small puddles of water in cold water supply line. Adjust the thermopile voltage. This condition the drain pan or hear sizzling sounds PRV to between 50 and 60 psi. as water drips on the burner, the may clear up as the tank begins to water heater may be producing warm. See “2 Flashes” on page 10 • Thermal Expansion Tank. Install condensation. Condensation may drip a Thermal Expansion Tank. If a Thermal Expansion Tank is already onto the burner or other hot surfaces Leaking Plumbing Connections to produce a sizzling sound. On some installed and the T&P Relief Valve models, this may actually cause the If there’s water on the floor around discharge pipe drips, the Thermal pilot to go out. the bottom of the water heater, check Expansion Tank may be pressurized the plumbing connections on top of to the wrong pressure or the internal Condensation usually occurs when the the tank. Use a dry paper towel to bladder may be defective. Refer to water heater tank is full of cold water. wipe around the hot and cold pipe the instructions that came with the Condensation will most likely occur: connections on top of the water Thermal Expansion Tank for more • During holidays, weekends, or heater. If the paper towel is wet after information. family gatherings when there is an wiping a connection, repair the leak(s). • Debris. In rare cases, debris can increase in your home’s hot water stick inside the T&P relief valve usage. Drips from the T&P Relief Valve preventing the valve from seating • During the winter and early spring Discharge Pipe fully. In that case, the T&P relief months when incoming water valve discharge pipe will drip. You temperatures are at their lowest. A small amount of water dripping from may be able to clear debris from • If the water heater is a new the temperature and pressure (T&P) the T&P Relief Valve by manually installation. relief valve usually means the home’s operating the valve, allowing small water pressure is too high or you quantities of water to flush out the • If a large amount of hot water is need a properly sized and pressurized debris. See the label on the T&P used in a short period of time. thermal expansion tank. A large relief valve for instructions. amount of hot water coming from the • If the water heater is too small for If the water pressure is between 50 T&P discharge pipe may be due to the the home’s hot water demands. and 60 psi, a thermal expansion tank is tank overheating. In most cases, condensation installed and properly pressurized, and should disappear once the water WARNING! Do not cap or plug the the valve has been cleared of any debris, heater reaches normal operating T&P relief valve or discharge pipe, and it still drips, the valve may be broken. COMMON ISSUES COMMON temperature, or when the home’s hot and do not operate the water heater Install a new T&P relief valve. water demands return to normal. without a functioning T&P relief Valve. This could cause an explosion. If the water heater is too small for the home’s typical hot water demands, Refer to Figure 1 on page 6 while the water heater may produce reviewing this section.
Residential Standard Gas Water Heater Service Handbook • 15 Temperature Too High Low Water Pressure Water Odor Check both the cold and hot water at a Harmless bacteria normally present Scalding Risk sink to determine if the lower pressure in tap water can multiply in water A water heater can is only on the hot water side. If the low heaters and give off a “rotten egg” make water hot pressure is on the hot water side only, smell. Although eliminating the enough to cause the primary causes of this are: bacteria that causes “smelly water” severe burns instantly, resulting • Melted heat traps or dip tube. with a Chlorination system is the only in severe injury or death. Higher Soldering copper pipes while they are sure treatment, in some cases, the temperatures increase the risk of connected to the water heater can standard anode rod that came with the scalding, but even at 120°F, hot water melt the heat traps inside the hot and water heater can be replaced with a can scald. See Table 2 on page 8 cold water connections or the dip tube special zinc anode rod which may help before proceeding. Thermostatic (cold water side). Melted heat traps or reduce or eliminate the odor. Contact mixing valves at each point of a melted dip tube can restrict the flow Technical Assistance for availability. use reduce the risk of scalding. of hot water. If that’s the case, replace NOTE: To protect the tank, an anode rod the heat traps or dip tube. If the water temperature is too hot: must be installed in the water heater at • Partially closed supply valve. Open all times or the warranty is void. • Install or adjust the thermostatic the water heater’s supply valve fully. mixing valves for each point-of-use In cases where the “rotten egg” smell (see manufacturer’s instructions), or is pronounced, you can raise the tank temperature to 140°F in order to • Adjust the temperature setting on reduce bacteria growth in the tank. the water heater. See “Temperature Settings” on page 7. WARNING! Higher temperatures increase the risk of scalding. If you set the temperature setting higher than 120°F, thermostatic mixing valves at each point-of-use are particularly important. See “Temperature Settings” on page 7. COMMON ISSUES COMMON
16 • Residential Standard Gas Water Service Handbook SERVICE PROCEDURES
Removing the Manifold/ 8. Remove the screws (1/4” nut Replacing the Pilot/ driver) securing the manifold/ Burner Assembly burner assembly to the combustion Thermopile Assembly 1. Turn the gas control/temperature chamber. (Figure 16.) knob to the “OFF” position (Figure 9. Carefully remove the manifold/ A. Removing the Old Pilot/ 6 on page 9). burner assembly from the Thermopile Assembly from 2. Before performing any combustion chamber. BE SURE NOT the Manifold Assembly TO DAMAGE ANY INTERNAL PARTS. maintenance, it is important to 1. Remove the manifold door turn off the gas supply to the water GAS CONTROL VALVE/THERMOSTAT THERMOPILE assembly as described in heater at the manual gas shut- GAS CONTROL/ WIRE CONNECTIONS TEMPERATURE KNOB “Removing the Manifold/Burner off valve (Figure 1, p. 6). This VAC Assembly” section. valve is typically located beside the PIEZO IGNITER BUTTON water heater. Note the position of VIEWPORT THERMAL 2. Remove the burner to access the shut-off valve in the open/on SWITCH the pilot/thermopile assembly. OUTER DOOR (TCO) position, then proceed to turn it NOT SHOWN Remove and keep the screws off. MANIFOLD SCREWS (2) securing the burner to the manifold (Figure 17.) IMPORTANT: DO NOT 3. With the unit shut-off, allow Figure 16. remove the orifice. sufficient time for the water heater to cool before performing any 3. Remove the screw securing the maintenance. pilot/thermopile assembly to the Removing the Burner pilot bracket and keep for reuse GAS CONTROL/ TEMPERATURE KNOB from the Manifold/ later (Figure 18.) Burner Assembly 4. Lift the retainer clip straight up VAC from the back of the manifold Natural Gas (Low Nox) & L.P. Gas I I ER component block (using a flat- BUTTON I E Burner blade screwdriver), then remove IRE I I ER (RIGHT 1. Take off the burner by removing the the manifold component block LEAD SIDE) IRE two (2) screws located underneath from the manifold door. See Figure PILOT RED IRE the burner (Figure 17.). 18. IMPORTANT: Be careful not I I ER U E (LEFT SIDE) to bend or alter the position of IRE 2. Check the burner to see if it is dirty MANIFOLD TUBE the pilot tube. It will be used as a or clogged. The burner may be bending template for the new pilot Figure 15. cleaned with soap and hot water. assembly. Note the placement/ IMPORTANT: DO NOT remove the 4. Remove the outer door. order of the wires in the manifold orifice. 5. Disconnect the following from the component block.
gas control valve/thermostat: pilot UR ER SCOOP PI O SSE 5. Lift the pilot/thermopile assembly tube (7/16” wrench), igniter wire SO E ODE S O O VIE (including the igniter wire) from (from the igniter lead wire), and the manifold assembly. manifold tube (3/4” wrench). See SCRE S PI O ER OPI E I O D SSE SCRE Figure 15. U E CO EC ORS UR ER D O ER I I S O S O PROCEDURES SERVICE 6. Disconnect the white and red I I ER OR C RI wires from the gas control valve/ IRE UR ER thermostat (Figure 15). Use RE I ER O O VIE C IP needle nose pliers to grip the I O D CO PO E connector(s). IMPORTANT: Grip OC RED IRES O the connector carefully to prevent Figure 17. THERMAL SWITCH (2) damage. Do not grip or pull the PI O U E I O D DOOR wires themselves. Figure 18. 7. Grasp the manifold tube and push down slightly to free the manifold tube and pilot tube.
Residential Standard Gas Water Heater Service Handbook • 17 B. Installing the New Pilot/ 4. Reinstall the manifold component 2. Follow the Lighting Instructions to Thermopile Assembly block in the manifold door. Ensure turn off the water heater and allow that the pilot tube and wires are it to cool for 10 minutes before 1. Read this step carefully before positioned as shown in Figure 21. attempting to clean the base-ring proceeding. Using the old pilot/ 5. Carefully bend the new pilot tube filter. pilot tube assembly as a guide, to match the bend of the manifold 3. Use a vacuum cleaner with a hose bend the new pilot tube to match tube. NOTE: When bending, DO attachment to remove any dust or the old one. Make only the bends NOT crimp or crease the pilot tube. debris that may have accumulated closest to the pilot before going to on the filter. NOTE: If you are the next step. 6. Before you proceed to the next step, install the new brass ferrule unable to inspect or clean the base- 2. Route the new pilot tube and nut in the gas control valve/ ring filter, follow the “Cleaning the wires through the opening in the thermostat’s pilot tube opening, Combustion Chamber and Flame manifold door. See Figure 18 on HAND TIGHT ONLY. Arrestor” instructions. page 17. 7. Install the manifold/burner 4. After the base-ring filter has PI O ER OPI E SSE been cleaned, follow the Lighting I I ER assembly. CO EC OR Instructions to return the water heater to service. PI O ER OPI E RED (+) THERMAL SWITCH WIRE CO EC S O E S CO RO V VE ER OS PI O ER OPI E WHITE (-) THERMOPILE CO US IO C ER SSE IRE CO EC S O E S E RRES OR CONNECTOR(S) CO RO V VE DOOR S E (CONNECT AT ER OS S CO RO V VE THERMOSTAT) ER RED ER S I C IRE S I C I O D CO EC IO S CO EC ORS COMPONENT I O D DOOR (RED WIRES) OC
OR C RI PI O U E O S O SE RI I ER Figure 19. Figure 22. IGNITER WIRE PASSES THERMOPILE WIRES PASS ROU CE ER O THROUGH TOP HOLE OF ORI ICE MANIFOLD COMPONENT MANIFOLD COMPONENT (COMPONENTS) BLOCK (SMALLEST HOLE) OC PI O U E ER OPI E Cleaning the PILOT TUBE PASSES THROUGH BOTTOM HOLE OF MANIFOLD COMPONENT BLOCK (LARGEST HOLE) Combustion Chamber ESE O P R S E Figure 21. PI O CO I ED O SO E ODE S and Flame Arrestor PI O R C E PI O SSE OR C S UR ER O S O 1. Follow procedure outlined in E P ODED VIE O PI O ER OPI E SSE “Removing the Manifold/Burner OR I OR IO PURPOSES O E PI O ER OPI E External Inspection and SSE S OU D E I S ED SERVICED S SI E U I Assembly.” DO O DIS SSE E Cleaning of the Base- 2. Use a vacuum cleaner/shop vac Figure 20. Ring Filter to remove all loose debris in SERVICE PROCEDURES SERVICE 3. Using the pilot screw removed 1. At least annually, check the base- the combustion chamber. See earlier, attach the new pilot/ ring filter for any dust or debris that Figure 22. Use compressed air to thermopile assembly. Reattach may have accumulated on the filter clear any dust or debris that may the burner to the manifold using screen. See Figure 22. NOTE: If the have accumulated in the flame- the screws removed earlier. NOTE: water heater is located in an area arrestor. (To clean the flame If your burner includes a burner that is subjected to lint and dirt, arrestor, you may use a soft plastic scoop, make sure that it is oriented it may be necessary to check the brush under water heater. Vacuum to the pilot side of the manifold base-ring filter more frequently. lint from brush. Repeat until brush tube. See Figure 17 on page 17. is clean.)
18 • Residential Standard Gas Water Heater Service Handbook 3. Reassemble following the 4. Inspect the door gasket and make 9. Turn on the gas supply to the water procedure under “Replacing the sure there is no fiberglass insulation heater at the manual gas shut-off Manifold/Burner Assembly.” between the gasket and the valve. (Figure 1, page 6). combustion chamber. (Figure 22.) 10. Follow the lighting instructions Replacing the Manifold/ 5. Tighten the two screws that secure on the front of the water heater. the manifold/burner assembly to With the main burner lit, check Burner Assembly the combustion chamber. (Use a for leaks at the manifold and 1/4” nut driver.) There should be no pilot connections by brushing on Explosion Risk space between the gasket part of an approved noncorrosive leak the manifold door and combustion detection solution. If such a solution WARNING! chamber is not available, use a mixture of hand dish washing soap and water • Tighten both manifold door screws IMPORTANT: Do not operate the (one part soap to 15 parts water) securely. water heater if the door gasket or childrens’ soap bubble solution. does not create a seal between the • Remove any fiberglass between Bubbles forming indicate a leak. manifold door and the combustion gasket and combustion chamber. Correct any leak found. chamber. • Replace viewport if glass is missing 11. Verify proper operation, then 6. Reconnect the manifold tube (3/4” replace the outer door. or damaged. wrench) and pilot tube (7/16” wrench) • Replace manifold component block to the gas control valve/thermostat. if it is missing or has been removed. See Figure 15 on page 17. Do not Testing the Igniter cross-thread or apply any thread System • Replace door gasket if it is sealant to the fittings. damaged. The piezoelectric igniter system consists IMPORTANT: If you were supplied of an igniter button, an electrode, and • Failure to follow these instructions with a new ferrule nut in a parts kit, wire. The pilot is ignited by an electric can result in death, explosion, or follow these steps to connect the spark generated when the igniter fire. pilot tube: button is pressed. See Figure 24. 1. Check the door gasket for damage A.) Install the ferrule nut into the gas ER OPI E or imbedded debris prior to valve at the pilot tube location, PI O installation. See Figure 22. PI O hand tight only. ER OPI E R C E 2. Inspect the viewport for B.) Insert the pilot tube into the VAC damage and replace as required ferrule nut until the tube (Figure 16, page 17). bottoms out, then tighten the E EC RODE
3. Insert the new manifold/ nut with a 7/16” wrench until IRE O E EC RODE burner assembly into the burner the crimp connection seals to I I ER U O compartment, making sure that the pilot tube. Figure 24. the tab of the manifold tube C.) Continue to tighten until the nut engages the slot of the bracket is tight in the gas valve. To test the igniter system, follow these inside the combustion chamber. steps: 7. Connect the white and red wires to See Figure 23. 1. Turn off the gas to the water heater
the gas control valve/thermostat PROCEDURES SERVICE as shown in Figure 15, page 17. at the manual gas shut-off valve. C OSE UP I SIDE VIE O (See Figure 1, page 6.) E CO US IO C ER Also, ensure that the red thermal switch wires are connected to the 2. Watch the electrode tip while thermal switch (TCO switch) on the activating the igniter. (If the room manifold door. See Figure 21 on is dim enough, try looking through
S O page 18. the view port [Figure 16].)
IP R C E 8. Reconnect the igniter wire. (Figure A. A visible spark should jump from I O D U E 15, page 17). the electrode. To avoid shock, do not touch the burner or any metal Figure 23.
Residential Standard Gas Water Heater Service Handbook • 19 part on the pilot or pilot assembly. Figure 1, page 6. Disconnect the “Lighting Instructions” on the If no spark is visible, check the the remaining pipe from the gas front of the water heater. wire connections and make sure control valve/thermostat. TEFLON® is a registered trademark of that the electrode is not broken. 6. To remove the gas control valve/ E.I. Du Pont De Nemours and Company See also “Connections Check” (p. thermostat, thread a 4” section of 11). gas pipe into the inlet and use it to Draining and Flushing B. Replace the igniter if defective turn the gas control valve/thermostat (i.e., gas control valve/ (counterclockwise.) Do not use a WARNING! Hot Water Discharge thermostat and/or pilot/ pipe wrench or equivalent to grip Hazard: thermopile assembly). Dirt and body. Damage may result, causing • Keep clear of temperature/ rust on the pilot or electrode tip leaks. Do not insert any sharp objects pressure relief valve discharge. can prevent the igniter spark. into the inlet or outlet connections. • Temperature limiting valves are Wipe clean with a damp cloth Damage to the gas control valve/ available. and dry completely. Rust can thermostat may result. • Read instruction manual for be removed from the electrode information on a safe temperature tip and metal surfaces by lightly Replacing the Gas Control Valve/ setting. sanding with an emery cloth or Thermostat: fine grit sandpaper. It is recommended that the tank be To replace the gas control valve/ drained and flushed every 6 months thermostat, reassemble in reverse to remove sediment which may build Removing and Replacing order. When replacing the gas control up during operation. The water heater the Gas Control Valve/ valve/thermostat, thread a 4” section should be drained if being shut down of gas pipe into the inlet and use it to during freezing temperatures. To drain Thermostat turn the gas control valve/thermostat the tank, perform the following steps: IMPORTANT: This water heater has a (clockwise). DO NOT OVER TIGHTEN; damage may result. 1. Turn off the gas to the water heater resettable thermal switch installed. Do at the manual gas shut-off valve. not attempt to disable or modify this • Be sure to use approved Teflon® feature in any way. Use only factory tape or pipe joint compound on the 2. Open a nearby hot water faucet authorized replacement parts. gas piping connections and fitting until the water is no longer hot. on the back of the gas control valve 3. Close the cold water inlet valve. Removing the Gas Control that screws into the tank. 4. Connect a hose to the drain valve Valve/Thermostat: • Be sure to remove the pilot ferrule and terminate it to an adequate 1. Turn the gas control/temperature nut from the new gas control valve/ drain or external to the building. knob to the “OFF” position. thermostat. 5. Open the water heater drain valve (Figure 6, page 9.) • Turn the main gas supply on and and allow all of the water to drain 2. Turn off the gas at the manual shut- check the gas supply connections from the tank. Flush the tank with off valve on the gas supply pipe. for leaks. Correct any leak found. water as needed to remove sediment. (Figure 1, page 6.) Next, light the pilot and main 6. Close the drain valve, refill the tank, 3. Drain the water heater. Refer to burner, then check the manifold and restart the water heater as the “Draining and Flushing” section tube and pilot tube connections directed in the lighting instructions. for leaks. Correct any leak found.
SERVICE PROCEDURES SERVICE and follow the procedure. (The lighting instructions are Use an approved noncorrosive posted on the front of the water 4. Disconnect the igniter wire from leak detection solution. If such heater.) Ensure that the water the igniter lead wire. Use needle a solution is not available, use heater is full of water before you nose pliers to disconnect the a mixture of hand dish washing red (+) and white (-) thermopile soap and water (one part soap to light the pilot. wires. Disconnect the pilot tube 15 parts water) or childrens’ soap If the water heater is going to be (7/16” wrench) and manifold bubble solution. Bubbles forming shut down for an extended period, tube (3/4” wrench) at the gas indicate a leak. the drain valve should be left control valve/thermostat. See open. IMPORTANT: Condensation Figure 15 on page 17. • Be sure tank is completely filled with water before lighting and may occur when refilling the tank and 5. Disconnect the ground joint activating the water heater. Follow should not be confused with a tank union in the gas piping. See leak.
20 • Residential Standard Gas Water Heater Service Handbook SUPPLEMENTS
EVALUATING Household Appliances: ventilation, contact your local gas utility company or code officials for a safety Gas Burning Appliance BTU/HR Rating COMBUSTION AND inspection. Gas Water Heater VENTILATION AIR The following instructions will help SUPPLY determine if it may be possible to install without outside ventilation. Even if WARNING! Gas water heaters this may be possible, you will need to require an adequate source of clean air conduct the vent draft test on page 11 for combustion and ventilation. Total when installation is finished. If there is Without sufficient air, a water heater not enough ventilation, you will need to will have frequent pilot outages and Table 2 provides examples of minimum ventilate with outside air. may emit excessive and abnormal square footage (area) required for amounts of carbon monoxide. various BTU/HR totals. Areas used for Check for Chemicals: storage or which contain large objects Before beginning: Installations where corrosive chemicals containing less air than is assumed for may be present require outside air. Calculate total BTU/HR rating of all the room sizes in Table 4. See Option A appliances Air for combustion and ventilation for more specific calculations. must be clean and free of corrosive or To calculate the combustion air and Table 4. acid-forming chemicals such as sulfur, ventilation required, add up the total BTU/HR Minimum Typical fluorine, and chlorine. Ventilation with BTU/HR ratings of all gas burning Square Room with outside air will reduce these chemicals, appliances (e.g., water heaters, furnaces, Feet with 8’ Ceiling but it may not completely eliminate 8’ Ceiling clothes dryers) in the same area. them. Failure due to corrosive chemicals 30,000 188 9 x 21 is not covered by the warranty. Examples A water heater’s BTU/HR rating is on its 45,000 281 14 x 20 of locations that require outside air due data plate, located next to the gas control 60,000 375 15 x 25 to chemicals include: valve/thermostat. The BTU/HR ratings 75,000 469 15 x 31 should be on the other appliances’ data • Beauty salons 90,000 563 20 x 28 plates. If you have trouble determining • Photo processing labs 105,000 657 20 x 33 the BTU/HR ratings, contact the • Indoor pools 120,000 750 25 x 30 manufacturer. NOTICE: If you are • Laundry, hobby, or craft rooms replacing an old water heater with one 135,000 844 28 x 30 • Chemical storage areas that has a higher BTU/HR rating, the Products such as aerosol sprays, amount of ventilation required may be Option A: Installation without greater. detergents, bleaches, cleaning solvents, outside ventilation (not gasoline, air fresheners, paint and Example: recommended) varnish removers, and refrigerants Gas Burning Appliance BTU/HR Rating Ventilation with outside air is should not be stored or used near the Gas Water Heater 40,000 recommended for all installations. Even water heater. Furnace 75,000 if the water heater is installed in a large, A1: Calculate the air volume of Dryer 20,000 open room inside the house, outdoor the room air is usually needed because modern homes are very tightly sealed and Air requirements depend on the size of often do not supply enough air to the the room. Total 135,000 water heater. However, when installed Floor Area (Square feet) X Ceiling Height in a large indoor space, it may be (feet) = Room Volume (cubic feet)
possible to provide enough air without If there are large objects in the room SUPPLEMENTS outside ventilation. If you are unsure (e.g., refrigerator, furnace, car), subtract if the installation location has enough their volume from the volume of the
Residential Standard Gas Water Heater Service Handbook • 21 room to get a better estimate of the air must be within 12 inches from the floor B4: Calculate minimum size of available. and the second opening must be within vent openings and ducts 12 inches from the ceiling. Although a Room Volume – Object Volume = Air The vent cross-sectional area needed single opening is not preferred, you may Volume to provide the free area depends on the use a single opening to outside air if the A2: Calculate required air volume covering on the vent openings. Typical minimum free area is sized according vents use louvers or grilles to protect A water heater installed in an unconfined to Table 5. Two openings must be used the opening. The louver or grill itself attic or garage requires that the space when ventilating with air from another blocks some of the free area, so the be at least 50 cubic feet per 1,000 BTU/ room. HR of the total input for all gas burning opening may need to be larger to meet The outside air can be taken from a crawl appliances in the same area. the minimum free area requirements. space or attic open to the outdoors and Use the following formula to calculate [Total BTU/HR/1000] x 50 = Cubic feet adequately ventilated. You may use the required cross-sectional area: of air required. vertical or horizontal ducts. Example: Cross-sectional area = minimum free B2: Determine type of area required ÷ percent free area of (135,000 / 1000) x 50 = 6,750 ventilation covering (in decimals – e.g., 60% = .6) If the air volume of the room is less There are several types of ventilation For example, an installation area that than the required air volume, you must that can be used : requires openings with 100 square provide two permanent outside air 1. Direct to outdoors inches of free area would need 134 openings that draw in sufficient air. Use 2. Vertical ducts square inch openings if using metal Option B. louvers rated at 75% free area (100 sq. 3. Horizontal ducts If the air volume of the room is greater in. ÷ .75 = 134 sq. in.). than the required air volume, it may 4. Single opening (not recommended; must be at least 100 square inches. If you do not know the % free area for a be possible to install the water heater louver or grill, use the following values: without outside ventilation. Not appropriate for confined spaces smaller than 50 cubic feet • For wood louvers or grilles: 20% A3: Check that combustion per 1,000 BTU/HR as calculated in • For metal louvers or grilles: 60% ventilation is adequate section A or when getting air from Follow these rules to ensure that vents Because modern homes are often another room.) and ducts provide adequate air flow: well-sealed to prevent drafts, even a 5. From a larger room inside the large room may not provide enough house (not recommended – refer • Each vent opening must be no combustion air without ventilation. to section A above to determine smaller than 100 square inches . To confirm that your installation has if the combined volume of • Ducts must have the same cross- enough combustion air, conduct the the rooms may be adequate). sectional area as free area of the vent draft test on page 11 when opening. installation is finished. B3: Determine minimum free • Rectangular ducts must have a Option B: Install with outside area required for each vent minimum dimension of no less ventilation opening than three inches . • All screens must have mesh ¼” or Ventilation with outside air is The size of the vent openings depends larger. recommended, and, for most on the total BTU/HR rating of all installations, is needed. There may be appliances in the space (use your • Moveable louvers must be locked existing ventilation that is adequate, or calculation from “Before beginning”) open or interconnected with the you may need to add more ventilation. and the type of vent used. Table 5 equipment so that they open provides the minimum free area for automatically during operation. Supplying outside air to typically
SUPPLEMENTS each vent opening depending on the requires two openings. One opening • Keep louvers and grills clean and type of ventilation. free of debris or other obstructions.
22 • Residential Standard Gas Water Heater Service Handbook 1 Table 5. Combustion Air Supply Options ATTIC INSTALLATIONS Minimum Free Area of Permanent WARNING! Openings for Ventilation and • In all cases, a water heater must be Combustion Air Supply – All Air from installed according to its installation Outdoors Only. manual. • Consult the local codes of your Based on the total BTU/HR input area for specific ventilation and rating for all gas burning appliances combustion air requirements. In the within a confined space. absence of local codes, follow the Opening Source Minimum Free Area National Fuel Gas Code (ANSI Z223.1- Per Opening (sq. in.) current edition). *Direct to outdoors 1 sq. in. per • Failure to follow these warnings 4,000 BTU/HR Direct to outdoors openings (see Figure 25) Figure 25. can lead to death, serious injury, or property damage. Vertical ducts 1 sq. in. per 4,000 BTU/HR (see Figure 26) Overview Horizontal ducts 1 sq. in. per Attic installations are common in 2,000 BTU/HR (see Figure 27) some parts of the country. In most cases, such installations are trouble Single Opening 1 sq. in. per free. However, problems may arise 3,000 BTU/HR (see Figure 28) from poor ventilation, high ambient temperatures, water leaks, and other *These openings connect directly with the outdoors through a potential hazards. Such issues include ventilated attic, a ventilated crawl Vertical duct openings pilot outage, water damage to the space, or through an outside wall. Figure 26. living spaces below, and elevated water temperatures. Even so, these B5: Check that air source is clean problems can be addressed. Some of and free of chemicals the potential solutions are listed below. Air for combustion and ventilation Pilot Outage must be clean and free of corrosive or flammable chemicals. A failure due to Pilot outage is more common in attic corrosive chemicals in the air is not spaces and hot environments than covered by the warranty. Combustion air in other installations. The following factors can contribute to pilot outage, must be free of acid-forming chemicals either individually or in combination: such as sulfur, fluorine, and chlorine. Be sure that air at the vent inlets is free of Horizontal duct openings • Elevated air temperature Figure 27. such chemicals. • Insufficient makeup air (air needed for the proper ventilation of B6: Check that combustion combustion gases) ventilation is adequate • Blocked air screen or flame arrestor To confirm that your installation has • Improper venting of the water heater enough combustion air, conduct the vent draft test on page 11 when • Decompression installation is finished. • Wind
1 Originally published as “Issues SUPPLEMENTS Related to Gas Water Heaters Installed in Attics (Atmospheric Vent)” Single opening (324841-000). Figure 28.
Residential Standard Gas Water Heater Service Handbook • 23 Elevated Air Temperature: Volume Requirement Formula: hrs of total input for all gas-fired appliances in the attic. Also, the In some areas, attics can reach in excess (Inputs in Btu/hr ÷ 1,000) 50 = size of the opening must not be less of 160°F. Such high temperatures can minimum volume in cubic feet for than the sum of the areas of all vent cause atmospherically-vented water all gas appliances in the attic heaters to stall and shut down. connectors in the space. Once you know the volume • be protected by a louver or grille as Why? The flame arrestors, filters, requirement, you should compare it to and sealed combustion chambers described in the current edition of the actual volume of the attic. Use the National Fuel Gas Code. that make modern water heaters this formula to calculate the volume of flammable vapor ignition resistant the attic: Alternatively, you may be able to also make them more sensitive to increase the amount of makeup air high ambient temperatures. This is Attic Volume: by increasing vent capacity. Note, because high temperatures cause Length x Width x Height = however, that your venting must the air to expand, affecting draft and Attic volume in cubic feet be configured to provide proper air depleting the oxygen available to the For example, if the attic space is 40’ x 50’ flow. Also, the combined area of pilot. In other words, when the pilot x 8’, its volume would be 16,000 cubic the vent openings should be no less flame consumes the oxygen in the feet. To provide ample combustion air, than one square inch for every 3,000 sealed combustion chamber and that the attic volume should be greater than Btu/hrs of total input for all gas-fired oxygen isn’t replaced by a proper draft, the volume requirement. If it is not, appliances in the attic. (Note: The the flame will go out. This, in turn, will and pilot outages have been an issue, net free area will be listed in the shut down the water heater. try increasing the attic’s ventilation. vent’s product specifications, making verification easy.) This issue may be resolved by Ventilation is always critical. Oxygen increasing attic ventilation. Contact must be replaced as quickly as it is Contact a licensed contractor or a a licensed contractor or a roofing used. Otherwise, a pilot outage may roofing professional for guidance. professional for guidance. See also occur, causing the water heater to shut “Insufficient Makeup Air” down. Under normal circumstances, Blocked Air Screen or Flame Arrestor a well-ventilated attic of the proper Most gas water heaters today have Insufficient Makeup Air size should provide plenty of makeup Flammable Vapor Ignition Resistant Adequate make-up air is essential for air. However, you may need to (FVIR) designs. These designs include combustion. A water heater takes its increase ventilation if the attic is some type of screen/flame arrestor combustion air from the surrounding unusually “tight,” reaches extremely that reduces the likelihood that area, and that air must be replaced high temperatures, or contains more flammable vapors in the room will as quickly as the oxygen is consumed. than one gas-fired appliance. Before be ignited by the water heater’s pilot Two factors determine the availability doing so, though, check the vents to flame or burner flame. Of course, the of makeup air: the attic’s volume see if they are blocked. If they are, screens, filters and arrestors used in and the total combined area of the unblocking them may help to improve these designs must be kept clean so openings that provide outdoor air. ventilation and lower the ambient that combustion air can flow freely temperature. At a minimum, the attic should have into the water heater. Dust and other 50 cubic feet of volume per 1,000 Btu/ If you need more makeup air, consider airborne contaminants can block or hr of the total input. For example, if an additional opening to the outdoors reduce incoming air and cause the your water heater has an input of as described in the National Fuel Gas water heater to shut down. Screens 30,000 Btu/hr, the attic should have Code (ANSI Z223.1-current edition). and filters must be kept in place and a minimum volume of 1,500 cubic The opening should: cleaned regularly. (See p. 18.) This is especially important in areas that are feet under normal circumstances. • communicate directly with the not cleaned regularly, such as attics. This was calculated as follows: outdoors, (30,000 ÷ 1,000) 50 = 1,500. • commence within 12 inches from Improper Venting of the Water Heater the top of the attic enclosure, and SUPPLEMENTS Proper venting of the water heater • be sized at a minimum of one is crucial for trouble-free operation. square inch for every 3,000 Btu/ Verify the following:
24 • Residential Standard Gas Water Heater Service Handbook • The venting system must be installed For example, an attic may be cooled by • Sensors mounted in the metal drain according to the water heater’s an attic fan, designed to pull hot air out pan that trigger an alarm or turn installation instructions and local of the attic and move it to the outdoors. off the incoming water to the water codes. In the absence of local codes, This is a good solution for cooling an heater when leakage is detected. follow the National Fuel Gas Code attic, but it could cause problems for • Sensors mounted in the metal drain (ANSI Z223.1-current edition). an atmospheric gas water heater. If the pan that turn off the water supply • The draft hood must be installed attic doesn’t have adequate free-air to the entire home when water is properly and must not be modified openings, the attic fan could cause air detected in the drain pan. in any way. to flow backwards through the water heater vent, causing the pilot to go out. • Water supply shut-off devices that • The water heater must not be This, in turn, will force the water heater activate based on the water pressure common vented with any power to shut down. Increasing the number differential between the cold water vented appliance. or size of free air openings in the attic and hot water pipes connected to • Horizontal runs of vent should be may help to prevent this problem. See the water heater. sloped upward from the water heater “Insufficient Makeup Air” on p. 24. • Devices that will turn off the gas by at least ¼-inch per foot. Ensure supply to a water heater while at that there are no dips or sags in the Wind the same time shutting off its water vent run. Wind is only more critical for attic supply. • The vent run should include as installations when it occurs in few bends as possible. Each bend combination with one of the above Elevated Water Temperature increases resistance to the flow of factors. The pressure needed to stop a flue gasses. Refer to the applicable flue draft is less than 1/500th of an inch DANGER! installation code and the installation of water column. If the draft through • Water temperature over 120°F can instructions for the water heater. the flue stops, the water heater will cause severe burns instantly or death • Venting must be free of obstructions shut down. from scalds. and corrosion. • Children, disabled and elderly are at • There must be no separation of joints. Water Damage highest risk of being scalded. Each joint must be fastened by sheet A water heater must be installed in • Thermostatic mixing valves at each metal screws or other approved such a manner that if the tank or point of use reduce the risk of means. Also, vent must be supported connections leak, the flow will not scalding. properly to prevent sags and joint damage the living spaces below. A If the ambient temperature in the attic separation. Use of support straps or suitable metal drain pan should be is extremely high, it may gradually affect other approved means is acceptable. installed under the water heater. Metal the temperature of the water inside the drain pans are available at your local water heater. For example, assume that hardware store. The pan must have a Decompression a water heater is set to 120°F, but the minimum length and width of at least Decompression can cause or contribute attic maintains a temperature of 130°F 2” (5.1 cm) greater that the water to pilot outage. Decompression occurs or more during the summer months. heater dimensions and must be piped when the air near the water heater is Over time, the water temperature in to an adequate drain. Drain pan depth at slightly less pressure than the air the water heater may increase beyond must provide clearance for servicing outside the building. Inside the home, the desired 120°F. As a result, the the igniter and burner. However, even a classic decompression condition can water temperature at the outlet may with the use of a drain pan piped to a be caused by a large kitchen exhaust be higher than expected. drain, water damage can still occur. fan. The negative pressure can cause A remedy would be to decrease the This risk can be reduced further by air to flow backwards through the ambient temperature in the attic. This installing a leak detector or water shut- water heater vent, stall the air in the may be accomplished by improving off device. You can buy such devices flue, and cause the pilot to go out. The ventilation. However, in doing so, same is true for a water heater in an from plumbing supply wholesalers or be sure that you do not create a SUPPLEMENTS retailers. Examples are listed below: attic, but for different reasons. decompression situation (e.g., using an attic fan without adequate free
Residential Standard Gas Water Heater Service Handbook • 25 air openings). See “Pilot Outage: store or place objects on top of the Insufficient Makeup Air” and “Pilot FIELD water heater. Outage: Decompression” for more INSTALLATION OF • Install the draft hood securely to the information (pp. 24 & 25, 2 water heater and flue pipe according respectively). In the short term, DRAFT HOODS to the installation instructions. however, open a hot water faucet and The purpose of this section is to show These instructions were provided allow the water to flow until it reaches how to properly connect draft hoods with the water heater. a safe temperature. to single- and double-wall (Type B) • Do not use flex vent pipe or dryer vent pipe. These instructions cover vent pipe. 3-inch, 4-inch, and combination draft • Vent pipe should be made of hood sizes. galvanized steel. Do not use A draft hood is critical to the operation aluminum vent pipe. of a gas water heater. (It is attached • Always wear work gloves when between the heater’s flue outlet working with sheet metal parts. and the vent pipe.) When properly installed, the draft hood cools the Tools and Materials combustion products and allows them The following tools and materials to flow safely from the building. It may be required to install the draft also protects heater operation during hood and vent pipe. Other tools and updrafts and downdrafts that are materials may be needed. caused by indoor/outdoor air pressure differences. • Work Gloves • Flat-ended pliers WARNING! • Water Heater Installation Manual • 1/4-inch hex nut driver • The venting system shall comply • Screw driver with flat tip with applicable local and state/ • Powered screw driver tool (optional) provincial codes. The venting system • Tape measure (for checking sizes) shall also comply with the current • Sheet metal cutting tools (optional) edition of the National Fuel Gas Code ANSI Z223.1/NFPA 54 (U.S.A.) Types of Draft Hoods Covered in or the Natural Gas and Propane Installation Code CAN/CSA-B149.1 this Section (Canada). • Each standard vent gas water heater is supplied with a specific draft hood. This ensures the safe, correct 3-inch Draft Hood operation of the water heater. However, the draft hood must be installed correctly. • Do not use a draft hood other than the one that is supplied with the 4-inch Draft Hood water heater. • Do not re-use any previously installed draft hood. Previously used parts should be discarded. • Do not modify, cut, or bend a draft hood during installation. Combination Draft Hood (3-in./4-in.)
SUPPLEMENTS • Do not block or restrict the open areas around the draft hood. Do not Figure 29.
2 Originally published as 187010-000.
26 • Residential Standard Gas Water Heater Service Handbook Types of Vent Pipe Covered in the legs into the slots, then If you are connecting the draft this Section secure them with screws as hood to Type B vent pipe or to described in your installation vent pipe of a different size or • Single Wall - Galvanized Steel manual. brand, read the Coupling section • Double Wall (Type B) - Galvanized 3. Connect the draft hood to the before you proceed. Steel venting system as described below. P Installation Procedure IMPORTANT: The inside diameter of the vent pipe or draft hood Draft Hood 1. Determine the size of the draft connector may vary slightly by hood. manufacturer. Always verify that To determine the size of a draft hood, vent connections are secure and air measure across the portion that will fit tight. Figure 33. into the vent or vent connector. (Vent In instances where correctly- connection will be covered later.) matched pieces will not fit together, B. Verify that all vent connections Example: use flat-ended pliers to flare the are secure and air tight. end of the pipe or flatten its seam Measuring a Combination C. Secure the vent pipe to the draft Draft Hood joint. However, do not modify, cut, hood with self-drilling screws. or bend the draft hood. Also secure any new sections of vent pipe. To flare the end of the vent Use a minimum of three screws pipe, bend the edge outward per connection. Screws should all the way around the be evenly spaced. For example, perimeter (approx. 1/4-inch from the three screws should be spaced at edge). 120 degree increments around Figure 30. the perimeter of the vent pipe. 2. Install the draft hood to the water IMPORTANT: Only use screws heater according to the installation that are 5/8” long or less in manual. length. NOTE: There are two methods for Figure 31. Coupling securing a draft hood. Use only the method that applies to your water The opening of your draft hood will be either 3-inches or 4-inches in diameter. heater model. E P (You measured the diameter during • Lock-in Type: Some draft hoods Step 1 of the Installation Procedure have notches at the bottom of fl section.) each leg. Simply align the legs fl of the draft hood with the slots • If you are connecting double wall flatte (Type B) vent pipe to the draft hood, in the top of the water heater. Insert the legs, then rotate the you must use a Type B draft hood connector. Without this connector, draft hood. Ensure that the S draft hood is secure before you double wall vent pipe will not fit the proceed. draft hood properly. See Type B Draft Hood Connectors. • Push-in Type with screws: Most Figure 32. draft hoods are designed to be • Compare the size of your draft hood secured with screws (which are A. Fit the female end of the vent opening to the size of the vent pipe. provided). Align the legs of the pipe over the draft hood as If the vent pipe has a wider diameter draft hood with the slots in the shown below. Note that you may than the draft hood, use an adapter SUPPLEMENTS top of the water heater. Insert need to adjust or reposition the to connect them. See Figure 34 on vent pipe during this process. page 28.
Residential Standard Gas Water Heater Service Handbook • 27 • When transition to a larger vent Type B Draft Hood Connectors size is required, the vent transition Double wall (Type B) vent pipe will not connection must be made at the fit draft hoods properly. To ensure a Type B Vent Pipe draft hood outlet. Do not connect secure connection, use a Type B draft a 4-inch draft hood to 3-inch vent hood connector between double wall pipe. A draft hood must only be vent pipe and the draft hood. T connected to an equal or larger- Draft Hood sized vent pipe (as allowed by code). Type B vent connectors are available Connector in various sizes, including those shown Only use the draft hood that is supplied below. Draft Hood with the water heater.
Seal joint at bottom P Examples of Type B Draft Hood Connectors Figure 36. 3-inch Draft Hood NOTE: Be sure to secure the connections as described in step 3 of the Installation Procedure section. Figure 34.
• When two vent pipes are made by different manufacturers, they may T T not fit together properly. In such cases, use a universal adapter to join the vent pipes. (Follow the Figure 35. manufacturer’s instructions and all applicable code.) However, do not use a universal adapter to join the Figure 36 shows a typical connection draft hood to the vent pipe. Always between a draft hood and Type B vent verify that the vent connections are pipe. secure and air tight. SUPPLEMENTS
28 • Residential Standard Gas Water Heater Service Handbook NOTES NOTES
Residential Standard Gas Water Heater Service Handbook • 29 NOTES NOTES
30 • Residential Standard Gas Water Heater Service Handbook NOTES NOTES
Residential Standard Gas Water Heater Service Handbook • 31 Copyright © 2019. LOCHINVAR, LLC. ALL RIGHTS RESERVED.
ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED. IF YOU ARE UNSUCCESSFUL, CONTACT LOCHINVAR WATER HEATERS RESIDENTIAL TECHNICAL ASSISTANCE AT 1-800-722-2101 OR WWW.LOCHINVAR.COM.