63-2144-2 H705a Solid State Enthalpy Controller

H705A Solid State Enthalpy Controller

PRODUCT DATA FEATURES

¥Provides accurate solid state enthalpy changeover control in a corrosion-resistant, plate-mounted package.

¥ Mounting plate matches plate-mounted H205A Enthalpy Controller for easy replacement. Also matches electromechanical Barber Colman THC-2 Enthalpy Controller.

¥ Controls operation of the economizer outdoor air damper to provide free cooling on a signal from the cooling thermostat.

¥ Can be mounted in any position inside an economizer unit.

¥ One model can be used for both electronic and electromechanical systems.

¥Provides greater economizer savings when optional APPLICATION differential changeover control is used with a C7400A Sensor mounted in the return air duct.

The H705A Solid State Enthalpy Controller maximizes the ¥ Enthalpy setpoint (A,B,C,D) located on H705A Solid use of free outdoor air in place of the first stage of cooling in State Enthalpy Controller is used to select heating, ventilating and air conditioning (HVAC) economizer combination of air temperature and humidity that is systems. suitable for free cooling.

¥ Compact size and lightweight construction provide easy mounting in HVAC rooftop unit.

¥ Quick-connect terminals reduce installation time.

Contents

Application...... 1 Features ...... 1 Specifications ...... 2 Ordering Information ...... 2 Installation ...... 3 Operation ...... 8 Checkout and Troubleshooting ...... 9

Electrical Ratings: SPECIFICATIONS Input Voltage: 24 Vac, 50/60 Hz. Power Consumption: 5.5 VA. Model: Relay Contact Ratings at 24 Vac: 1.5A run, 3.5A inrush. H705A Solid State Enthalpy Controller with mounting plate and 1/4 in. (6 mm) quick-connect terminals. For use Dimensions: with both electronic and electromechanical controls. See Fig. 1.

Humidity Sensing Element: Temperature Ratings: Capacitive film. Operating Ambient: -25°F to +125°F (-32°C to +52°C).

Temperature Sensing Element: Approvals: Thermistor. Underwriters Laboratories Inc.: Flammability Rating: UL94V-0.

Switching Action: Accessories: Single pole double throw (spdt) 1/4 in. (6 mm) quick-connect 4074EJM Accessory Kit (620 ohm resistor, jumper, 1.2K ohm terminals. Terminals 2 and 1 make with enthalpy increase checkout resistor). above setpoint. Terminals 2 and 3 make with enthalpy C7400A Solid State Enthalpy Sensor. decrease below setpoint. S963B1128 Minimum Position Potentiometer.

ORDERING INFORMATION

When purchasing replacement and modernization products from your TRADELINE¨ wholesaler or distributor, refer to the TRADELINE¨ Catalog or price sheets for complete ordering number.

If you have additional questions, need further information, or would like to comment on our products or services, please write or phone: 1. Your local Home and Building Control Sales Office (check white pages of your phone directory). 2. Home and Building Control Customer Relations Honeywell, 1885 Douglas Drive North Minneapolis, Minnesota 55422-4386

In Canada—Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V 4Z9. International Sales and Service Offices in all principal cities of the world. Manufacturing in Australia, Canada, Finland, France, Germany, Japan, Mexico, Netherlands, Spain, Taiwan, United Kingdom, U.S.A.

63-2144—2 2 H705A SOLID STATE ENTHALPY CONTROLLER

2-3/8 (60)

SIDE

7/32 (6)

TR TR1 B C SO A D

S R 4-7/32 (107)

3 4-11/16 S 2 1 (119)

13/16 (20) 4-1/4 (108) 5-15/16 (151) 6-7/16 (164)

FRONT BACK M12165

Fig. 1. Approximate dimensions of H705A Solid State Enthalpy Controller with mounting plate in in. (mm).

INSTALLATION CAUTION CAN CAUSE ELECTRICAL SHOCK OR When Installing this Product… EQUIPMENT DAMAGE. 1. Read these instructions carefully. Failure to follow them Disconnect power supply before installation. could damage the product or cause a hazardous condition. IMPORTANT 2. Check the ratings given in these instructions and on the Make sure the enthalpy sensor is not exposed to product to make sure the product is suitable for your rain, snow, or direct sunlight when selecting the application. location. 3. Installer must be a trained, experienced service technician. 4. After installation is complete, check out product operation as provided in these instructions.

3 63-2144—2 H705A SOLID STATE ENTHALPY CONTROLLER

Location » Remove screws from mounting plate and slide H205A clear of sheet metal. The H705A Solid State Enthalpy Controller can be mounted ¿ If wiring, housing and knob are in a position not in any position inside the outdoor air intake hood where it is exposed to weather, replace with H705A using existing exposed to freely circulating outside air and is protected from cutout and screw holes. rain or direct sunlight. The sensors perform best with an air ´ If unit is exposed to weather, relocate the H705A flow of at least 500 feet per minute. inside the outdoor air housing. Use the existing H205A wiring compartment for connection of additional wiring, For differential enthalpy control, install a C7400A Sensor in if necessary. the return air duct up to 200 feet from the controller. Use 18, 20 or 22 AWG wire for connecting the sensor to the controller. The L-shaped bracket can be used in a variety of ways to aid installation of the H705A. See Fig. 2 for L-shaped bracket Mounting dimensions and suggested mounting orientation. To replace H205A (less mounting plate): ³ Turn off power to H205A. Wiring · Disconnect H205A wires. » Remove H205A. ¿ Install H705A using L-shaped bracket (if required). See CAUTION Fig. 2. CAN CAUSE ELECTRICAL SHOCK OR EQUIPMENT DAMAGE. Mount the H705A in an area with adequate outdoor airflow Disconnect power supply before wiring. and protected from rain or direct sunlight. All wiring must comply with applicable local codes and To replace H205A (with mounting plate): ordinances. Follow wiring information furnished by the HVAC ³ Turn off power to H205A. equipment manufacturer or refer to Fig. 3 through 6 for typical · Disconnect H205A wires. wiring hookups.

5/8 (16)

1-13/32 (35)

4 -7/32 (107) 4 - 3/4 (120)

4 -7/32 (107) 17/32 (13) 2-1/4 (57)

13/16 (20)

11/32 (9) M15039

Fig. 2. Approximate dimensions of L-shaped bracket in in. (mm).

63-2144—2 4 H705A SOLID STATE ENTHALPY CONTROLLER

L1 TR W936 OR W945 (HOT) ELECTRONIC PANEL L2 TR 1

E1 E2 E3 M745 T1 ECONOMIZER MOTOR H705A OPTIONAL OPTIONAL C7400A MORNING TR 3 1 RWWARMUP 620 TR1 THERMOSTAT 2 OHMS L1 TR 2 (HOT) SR S L2 TR 3 1 3 4 WR B 2 1

S963A OR Q209 MINIMUM POSITION POTENTIOMETER

1 PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS 3 ENSURE THAT EQUIPMENT TRANSFORMER IS SIZED TO HANDLE REQUIRED. THE EXTRA LOAD OF THE ECONOMIZER AND ACTUATOR.

2 FACTORY INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE REMOVED ONLY IF A C7400A SENSOR IS ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY. M15037

Fig. 3. H705A used in electronic system.

W859D ECONOMIZER CONTROL PACKAGE RED BLUE VIOLET VIOLET BROWN BLACK/BLUE BLACK/RED BLACK/YELLOW YELLOW YELLOW B1 2 3 3 3 W1

WHITE/RED 2ND STAGE R1 COOLING T872 SPACE CONTACTOR MODUTROL¨ THERMOSTAT MOTOR (COOLING CIRCUIT) OPTIONAL H705A C7400A Y1 Y2 TR TR1 RC 5 SR 620 S OHMS 2 3 1 6 3 2 1 Y G C R L1 (HOT) L2 2 4 COOLING TRANSFORMER 1ST STAGE COOLING CONTACTOR

1 PROVIDE DISCONNECT MEANS AND OVERLOAD 4 ROOFTOP TERMINAL STRIP IS PART OF AIR CONDITIONING UNIT. PROTECTION AS REQUIRED. 5 FACTORY-INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD BE 2 FIELD CONTROL WIRING REQUIRED TO INTEGRATE REMOVED ONLY IF A C7400A SENSOR IS ADDED TO SR AND + FOR ECONOMIZER INTO UNIT. DIFFERENTIAL ENTHALPY.

3 FIELD WIRING REQUIRED TO PROVIDE ECONOMIZER AND 6 ENSURE THAT EQUIPMENT TRANSFORMER IS SIZED TO HANDLE MECHANICAL COOLING OPERATION IN EXISTING INSTALLATION. THE EXTRA LOAD OF THE ECONOMIZER AND ACTUATOR. M12162

Fig. 4. H705A used in electromechanical system.

5 63-2144—2 H705A SOLID STATE ENTHALPY CONTROLLER

T7300 T7300 T7400/W7000 SYSTEM EXISTING HVAC EQUIPMENT THERM- SUBBASE L1 L2 OSTAT H705A HVAC OPTIONAL (HOT) C7400A EQUIPMENT RH TR TR1 TERMINAL 9 STRIP SYSTEM 6 TRANSFORMER 2 SR 620 R RC S OHMS 3

2 1

3 3K 4

X Y1

C2 Y2 Y2

C1 W1 HEAT 1 Y1

H2 W2 HEAT 2 W2

H1 G FAN W1 4 5 FAN COOL1 G

COM 8 COOL 2

LED 1 BLACK/ YELLOW BLACK/RED W LED 2 TYPICAL W859D ECONOMIZER CONTROL PACKAGE

BLACK R MODUTROL¨ MIXED AIR OUTDOOR AIR TEMPERATURE 2K1 MOTOR CHANGEOVER CONTROLLER 7 SWITCH B BLUE B1 WR B A1 2K2 1K1 1K2 T675 LOW AMBIENT W1 RISE COMPRESSOR

BROWN LOCKOUT AUX R1 2K MINIMUM POSITION YELLOW T2 POTENTIOMETER YELLOW A2 T1 WR B 1K OPEN RED

VIOLET VIOLET 4K1 4K1 1 L2

4 L1 (HOT)

5 ECONIMIZER MOTOR SPRING RETURNS CLOSED ANY TIME FAN IS NOT RUNNING. 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD PROTECTION AS REQUIRED. 6 FIELD INSTALLED JUMPER. FACTORY-INSTALLED 620 OHM, 1 WATT, 5% RESISTOR 2 IMPORTANT: MIXED AIR SENSOR MUST BE LOCATED SHOULD BE REMOVED ONLY IF A C7400A SENSOR IS 7 DOWNSTREAM OF THE EVAPORATOR COIL IN THE DISCHARGE ADDED TO SR AND + FOR DIFFERENTIAL ENTHALPY. AIR DUCT TO PROVIDE ECONOMIZER LOW LIMIT FUNCTION. 3 ENTHALPY CONTROL MAKES TERMINALS 2-1 ON 8 24 VAC ONLY. ENTHALPY RISE, AND 2-3 ON ENTHALPY FALL. 9 MUST BE ABLE TO CARRY ADDITIONAL 6 VA LOAD OF 4 RELAY REQUIRED (R8222 OR SIMILAR). THERMOSTAT AND SUBBASE. M12167

Fig. 5. T7300/Q7300 using W859D Economizer Package with H705A in two-stage heating/two-stage cooling system, defeating economizer minimum position during unoccupied periods.

63-2144—2 6 H705A SOLID STATE ENTHALPY CONTROLLER

T7400/W7000 SYSTEM EXISTING HVACEQUIPMENT

L1 L2 L1 L2 H705A HVAC (HOT) OPTIONAL (HOT) 1 C7400A EQUIPMENT TR TR1 TERMINAL 1 STRIP SYSTEM TRANSFORMER 2 SR S 620 R OHMS 3

T7400 THERMOSTAT 2 1

WALLPLATE OR Q7400 SUBBASE 4 3K 5 4 1 3 2 R 1 W74OO CONTROL MODULE Y1 6

GND RC Y1 Y2 TD RELAY TR Y2 Y3 TR Y3 T74OOB ONLY: 24 VAC RH R W1 W1 HEAT 1 T7047C1025 H R OR T7022A1010 C W2 REMOTE SENSOR W3 4 W2 HEAT 2 R TDR 3 C G 6 T7400 2 G FAN 1 TDR

A COOL1 RED ECONO 8 COM AUX. ENTHALPY 6 B5RELAY SWITCH

3K1

COOL 2 BLACK/BLUE BLACK/RED W TYPICAL W859D ECONOMIZER CONTROL PACKAGE BLACK/ YELLOW BLACK R 2K1 MODUTROL¨ MIXED AIR OUTDOOR AIR TEMPERATURE MOTOR 7 CHANGEOVER CONTROLLER SWITCH B BLUE 2K2 B1 WR B T675 LOW 1K1 1K2 AMBIENT W1 RISE COMPRESSOR LOCKOUT R1 MINIMUM POSITION T2 POTENTIOMETER 2K T1 WR B YELLOW OPEN 1K RED YELLOW BROWN

RED VIOLET 3 VIOLET

1 FOR REMOTE MINIMUM POTENTIOMETER L1 L2 (HOT) 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD 5 PILOT DUTY RELAY REQUIRED (R8222N OR SIMILAR). PROTECTION AS REQUIRED. 6 THIS CONTROL IS AN EXISTING DEVICE, WHICH MAY BE A TIME 2 FACTORY-INSTALLED 620 OHM, 1 WATT, 5% RESISTOR SHOULD DELAY RELAY (TDR) OR L4604 (OR SIMILAR FAN CONTROL) IN BE REMOVED ONLY IF A C7400A SENSOR IS ADDED TO SR SOME SYSTEMS. AND + FOR DIFFERENTIAL ENTHALPY. 7 IMPORTANT: MIXED AIR SENSOR MUST BE LOCATED 3 YELLOW AND BROWN LEADS ARE SHORTED TOGETHER WHEN DOWNSTREAM OF THE EVAPORATOR COIL IN THE DISCHARGE SHIPPED. LEAVE SHORTED IF OPTIONAL FUNCTIONS ARE NOT USED. AIR DUCT TO PROVIDE ECONOMIZER LOW LIMIT FUNCTION.

4 ENTHALPY CONTROL MAKES TERMINALS 2-1 ON ENTHALPY RISE, 8 JUMPER TERMINALS 5 AND 6. M12166 AND 2-3 ON ENTHALPY FALL.

Fig. 6. H705A used with T7400C and W7400C with separate transformer in two-stage heating/three-stage cooling system with first stage dedicated to economizer setpoint, and either electromechanical economizer or mechanical cooling first stage.

7 63-2144—2 H705A SOLID STATE ENTHALPY CONTROLLER

Connect H705A terminals TR and TR1 to a 24 Vac power source with 5.5 VA excess capacity. The factory-installed OPERATION 620 ohm resistor between terminals SR and + must remain in place unless a return air duct mounted C7400A Sensor is Enthalpy Changeover Setpoint installed for differential enthalpy control. With single enthalpy control, the A,B,C,D enthalpy setpoint is used to adjust the enthalpy changeover characteristic as For differential enthalpy control: ³ shown in Fig. 7. The A setting provides the greatest energy Mount a C7400A Sensor, in any position, in the return savings. The factory-installed 620 ohm resistor must be in air duct where it will not interfere with damper blade place across terminals SR and +. movement or be exposed to mixed air. · Disconnect power from H705A terminals TR and TR1. » Remove 620 ohm resistor from between terminals SR Differential Enthalpy Changeover Setting and +. To operate in the differential mode: ¿ Connect S and + terminals of C7400A Sensor to ³ Remove the 620 ohm resistor from H705A terminals SR terminals SR and + of H705A. and +. · Connect a C7400A Sensor to H705A terminals SR When replacing an H705, the wires previously connected to and +. the H205A should be reconnected to the H705A as follows: » Turn the enthalpy setpoint potentiometer fully clockwise ³ Connect red wire to H705A terminal 2. to the D setting. · Connect yellow wire to H705A terminal 1. » Connect blue wire to H705A terminal 3.

85 90 95 100 105 110 (29) (32) (35) (38) (41) (43)

CONTROL CONTROL POINT 4 4 CURVE (APPROX. DEG.) 4 AT 50% RH 2 80 (27) A 73 (23) 4 0 B 70 (21) 4 C 67 (19) 8 D 63 (17) 3 75 (24) 4 36

0 32 70

(21) RELATIVE HUMIDITY (%) 3 8

2 100 65 90 26 80 ENTHALPY-BTU4 PER POUND DRY AIR (18) 70 2 2 60 60 2 50 0 (16)

A 40 2 8 55 (13) 1 B 30 6 50 1 4 (10) C 20 1 2 1 45 D (7) 40 (4) 10 35 (2)

B A D C

35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 (2) (4) (7) (10) (13) (16) (18) (21) (24) (27) (29) (32) (35) (38) (41) (43)

DRY BULB TEMPERATURE (APPROXIMATE) - FAHRENHEIT (CELSIUS) M9100A

Fig. 7. H705A performance characteristics for enthalpy changeover settings A,B,C, and D.

63-2144—2 8 H705A SOLID STATE ENTHALPY CONTROLLER

The economizer makes sure that the lowest enthalpy air is On a call for cooling by the space thermostat, the system used when cooling. If the outdoor air has lower enthalpy than operates as follows: return air, the outdoor air damper opens to bring in outdoor air for free cooling. When the enthalpy of the outdoor air is below the setpoint, the outdoor air damper is proportioned open (and return air Integrated Economizer System damper is proportioned closed) to maintain between 50°F and 56°F (10°C and 13°C) at the mixed/discharge air sensor. Operation: Single Enthalpy During economizer operation, the mechanical cooling is The purpose of an economizer is to use outdoor air for operated by stage 2 cooling on the space thermostat. cooling, whenever possible, to reduce compressor operation. The H705A economizer system, when wired as When the enthalpy of the outdoor air is above the setpoint, the shown in Fig. 3 through 6, responds to a signal from the outdoor air damper closes to its minimum position. A call for cooling thermostat. This H705A system utilizes a solid state cooling from the space thermostat brings on mechanical cooling. enthalpy changeover sensor. It responds to both dry bulb temperature and humidity, allowing the use of outdoor air at During the unoccupied period, the damper actuator returns higher temperature for free cooling when the humidity is low. the outdoor air damper to the fully closed position.

The economizer functions as a true first stage of cooling and provides maximum fuel economy during the cooling cycle. The economizer is automatically locked out during CHECKOUT AND TROUBLESHOOTING heating and holds the outdoor air damper at the minimum position setting. To perform checkout and troubleshooting, follow the procedures in Table 1.

Table 1. H705A Checkout and Troubleshooting. Checkout Procedure Response A. With factory-installed 620 ohm resistor connected across terminals SR and Light emitting diode (LED) should be off. + and outdoor air sensor disconnected (terminals So and + open), apply power Control terminals 2,3 open; terminals 1,2 (24 Vac) to terminals TR and TR1. closed. B. Disconnect factory-installed 620 ohm resistor from terminals SR and +. LED should turn on. Control terminals 2,3 closed; terminals 1, 2 open. C. Re-connect factory-installed 620 ohm resistor across terminals SR and +. LED should turn on, indicating low enthalpy. Connect 1.2K ohm checkout resistor (Accessory part number 4074EJM) across terminals SO and +. Turn enthalpy setpoint potentiometer to A. D. With resistors installed as in procedure C above; turn enthalpy setpoint LED should turn off, indicating high enthalpy. potentiometer to D. E. Connect a dc milliammeter between terminal SO of H705A and terminal S Milliammeter should indicate between 3 and of the outdoor air sensor. (See Fig. 8.) 25 mA if sensor is operating properly. If using differential enthalpy, the return air sensor may be checked by If milliammeter indicates zero, the sensor connecting a dc milliammeter between terminal SR of the H705A and terminal S may be wired backward. of the return air sensor. Checkout Using Environmentally Safe Coolant Spray Response A. Verify that the enthalpy sensor is connected to SO and + and factory- LED turns on in approximately one minute. installed 620 ohm resistor is connected across terminals SR and +. Control terminals 2, 3 closed; terminals Turn enthalpy setpoint to A. 1,2 open. With power connected, spray environmentally safe coolant, such as Envi-Ro-Tech 1672-10S, into upper left vent of sensor to simulate low enthalpy conditions. See Fig. 9. B. Disconnect power at TR and TR1. Control terminals 2,3 open; terminals 1,2 closed. C. If using differential enthalpy, verify that the outdoor sensor is connected LED turns on. to terminals SO and + and the return air sensor is connected to terminals Control terminals 2,3 closed; terminals SR and +. 1,2 open. Turn enthalpy setpoint to D (fully clockwise ). With power connected, spray environmentally safe coolant into upper left vent of H705A Enthalpy Sensor connected to SO and + to simulate low outdoor air enthalpy. See Fig. 9. D. Spray small amount of environmentally safe coolant into upper left vent of LED turns off. prereturn air C7400A Enthalpy Sensor connected to SR and + to simulate low Control terminals 2,3 open; terminals return air enthalpy. See Fig. 9. 1,2 closed.

9 63-2144—2 H705A SOLID STATE ENTHALPY CONTROLLER

ENTHALPY CHANGEOVER SETPOINT 24 VAC

TR TR1

B A 4 1 SO AD S

DC S R 2 MILLIAMMETER 620 OHM JUMPER

3 1 SENSOR ON BACK OF H705A. 2 JUMPER USED FOR SINGLE ENTHALPY CONTROL. 2 1 3 SWITCHES SHOWN IN HIGH ENTHALPY OR UNPOWERED STATE. 2-3 MAKE ON ENTHALPY DECREASE.

4 INSERT DC MILLIAMMETER BETWEEN SO AND S FOR CHECKOUT AND TROUBLESHOOTING.

LED LIGHTS TO INDICATE OUTDOOR AIR IS SUITABLE FOR FREE COOLING M12164

Fig. 8. Simplified schematic of H705A control circuit and meter location for checkout and troubleshooting.

SPRAY SMALL AMOUNT OF COOLANT INTO UPPER LEFT CORNER VENT OF ENTHALPY SENSOR CASE TO SIMULATE LOW ENTHALPY FOR CHECKOUT.

ENTHALPY SENSOR

ENVIRONMENTALLY SAFE COOLANT, SUCH AS ENVI-RO-TECH 1672-10S

M12163

Fig. 9. Use of environmentally safe coolant spray on sensor to simulate low enthalpy during system checkout.

63-2144—2 10 H705A SOLID STATE ENTHALPY CONTROLLER

11 63-2144—2 H705A SOLID STATE ENTHALPY CONTROLLER

Home and Building Control Home and Building Control Honeywell Asia Pacific Inc. Honeywell Inc. Honeywell Limited-Honeywell Limitée Room 3213-3225 Honeywell Plaza 155 Gordon Baker Road Sun Hung Kai Centre P.O. Box 524 North York, Ontario No. 30 Harbour Road Minneapolis MN 55408-0524 M2H 2C9 Wanchai Hong Kong Honeywell Latin American Division Honeywell Europe S.A. Miami Lakes Headquarters 3 Avenue du Bourget 14505 Commerce Way Suite 500 B-1140 Brussels Belgium Miami Lakes FL 33016

Helping You Control Your World¨

63-2144—263-2144—2 G.R. Rev. 1-97 Printed in U.S.A. 12 www.honeywell.com/building/components