7DEOHRI&RQWHQWV A3 Heaters and Defrosters

A3 Heaters and Defrosters

Table of Contents

Table of Contents ...... 1 List of Figures...... 1 Safety ...... 2 Figure 1—Control Panel...... 3 Warnings and Cautions ...... 2 Figure 2— Air Delivery Ports ...... 4 Introduction ...... 2 Figure 3—Inside Access Panel...... 6 Description of Operation ...... 2 Figure 4—Auxiliary Electric Heater ...... 7 Control Panel...... 2 Figure 5—Under the Seat Heaters...... 7 Heater ...... 4 Figure 6—Heater Boost Pump ...... 8 Heater Access...... 4 Figure 7—Engine Compartment Heater Defroster Fan Operation ...... 5 Piping...... 8 Heater Filter...... 5 Figure 8—Heater Cutoff Valve Location.. ...9 Driver’s Heater...... 7 Heater Core...... 7 List of Tables ...... 1 Under Seat Heater...... 7 Table 1—Defroster Fan Location by Defrosting...... 7 Option ...... 14 Boost Pump ...... 8 Table 2—Heater Cutoff Valve Engine Compartment Heater Piping...... 8 Location ...... 14 Heater Air Bleed Procedure...... 8 Table 3—Heater Water Capacity...... 14 Cutoff Valves ...... 9 Troubleshooting...... 9 List of Schematic ...... 1 Schematic 1—Kysor Heater ...... 11 Schematic 2— Level Sender...... 12 Schematic 3—Coolant Temperature Sender ...... 13

370-1 A3 Heaters and Defrosters

Safety Introduction The purpose of this safety summary is to ensure the The Blue bird All American bus uses a hot water safety and health of personnel and the protection of type heater. Heat is used from the engine coolant. equipment. The air is delivered though the heaters inside the body. All users of this publication shall read, understand, and apply this safety summary when performing The major components are listed as follows maintenance and operating procedures. • Controls • Front heater WARNINGS and Cautions • Defroster • All users of this publication shall read, and • Driver’s Heater • understand, all WARNINGS and Cautions. • Under Seat Heater • Booster Pump • Heater Air Bleed Procedure • Cutoff Valves

Description of Operation WARNINGS REFER TO A PROCEDURE OR PRACTICE, THAT, IF NOT Control Panel CORRECTLY OBSERVED, COULD RESULT IN INJURY OR DEATH. The operation/control switches for the heating and defrosting system is located on the main bus console, see Figure 1—Control Panel.

Air distribution from defroster and heater outlets can be adjusted by rotating diffusers, see Figure 1— Cautions refer to a procedure or practice, Control Panel. that, if not correctly observed, could result in damage to or destruction of equipment.

Make sure the engine is full and all coolant flow valves are open.

370-2 A3 Heaters and Defrosters

Figure 1—Control Panel

370-3 A3 Heaters and Defrosters

Heater 3. For access to the air delivery ports, see Figure Performance of body heaters depends on adequate 2—Air Delivery Ports. engine coolant temperature. Thermostat rating regulates the heat. The thermostat rating should not be higher than the recommended rating of the engine manufacture. Note Outlets that have a wedge shaped base are adjustable vertically and horizontally.

The main heater has a 3-speed control switch for manual speed operation.

The main heater has additional maximum output for flash defrosting for extreme conditions. All the air from the main heater blower can be used for defrosting by leaving the main outlet and foot warmer outlet closed. Figure 2—Air Delivery Ports Heater Access • The front heater can be accessed from two (2) 4. For access to the heater core and filter from the locations. inside, remove the inside heater access panel, see Figure 3—Inside Access Panel. 1. From the outside, at the front of the bus, right- hand side. The heating system depends on heat generated by the engine to heat the coolant to operating 2. From the inside at the dash panel, near the temperature. The coolant is pumped through the stepwell. heaters inside the bus body, and back to the engine.

Coolant flow varies with engine speed and increases with the use of the auxiliary water pump.

370-4 A3 Heaters and Defrosters

WITH A HOT ENGINE RAPID VENTING DO NOT OPERATE A DEFROSTER FAN OR RAPID REMOVAL OF RADIATOR WITHOUT THE FAN GUARDS CAP WILL ALLOW COOLANT TO INSTALLED. SPRAY OUT TO PREVENT SERIOUS BURNS SLOWLY • The three-speed motor is checked for function VENT PRESSURE, THEN REMOVE by operating the motor switch located on the RADIATOR CAP. control panel.

Defroster Fan Operation Heater Filter The defroster fan motor bearings are lifetime The protects the main heater coil. To lubricated and do not require maintenance. change the air filter remove the front access panel, see Figure 3—Inside Access Panel.

370-5 A3 Heaters and Defrosters

Figure 3—Inside Access Panel

370-6 A3 Heaters and Defrosters

Driver’s Heater Under Seat Heater The adjustable outlets on the dash can be directed to There are two physical under the seat heaters. There the driver. The auxiliary unit under the driver’s seat are seat mounted and floor mounted. The heaters are is a two-speed fan. Air can be directed to the options for the A3 All American, see Figure 5— driver’s left side and around the steering column Under the Seat Heaters. area, see Figure 4—Auxiliary Electric Heater.

Figure 5—Under the Seat Heaters

Figure 4—Auxiliary Electric Heater Defrosting During initial engine warm up, the defroster blowers Heater Core should be operated at low speed to preheat the inside of the windshield glass.

High humidity in cold is the cause for fogging of windows. That condition can be improved by WHEN USING COMPRESSED AIR FOR opening the forward drivers window to allow moist CLEANING, COOLING, OR DRYING, DO air to escape. NOT EXCEED 30 PSI. WEAR EYE PROTECTION AND DO NOT DIRECT COMPRESSED AIR AT SELF OR OTHERS.

The heater will be efficient when the core and fins are clean. The core can be cleaned with compressed air or by vacuum. Damaged fins should be straightened with a fin comb to prevent airflow restrictions. Assess to core is though the right front inside access panel.

370-7 A3 Heaters and Defrosters

Boost Pump Heater Air Bleed Procedure There is a 12 volt boost pump in the heater Use of ( type) is assembly, see Figure 6—Heater Boost Pump. recommended for summer or winter operation.

Use a 50/50 solution of antifreeze and water for freeze protection to approximately 30 degrees Fahrenheit below zero. Ultimate protection is attained at 68% antifreeze to 32% water. A 68 to 32 percent ratio will protect to approximately 92 degrees Fahrenheit below zero.

WITH A HOT ENGINE RAPID VENTING OR RAPID REMOVAL OF RADIATOR CAP WILL ALLOW COOLANT TO SPRAY OUT TO PREVENT SERIOUS BURNS SLOWLY VENT PRESSURE, THEN REMOVE RADIATOR CAP.

Figure 6—Heater Boost Pump • During the bleeding process, it is necessary to remove the radiator cap and refill the cooling Engine Compartment Heater Piping system. The refill is to ensure adequate • See Figure 7—Engine Compartment Heater coolant is available to replace purged air and Piping. coolant lost when bleeding.

1. Turn engine off to cool.

2. Shut all engine heater gate valves or clamp closed all heater hoses, as close to the engine as possible, see Figure 7—Engine Compartment Heater Piping.

EXHAUST GASES ARE HARMFUL AND POTENTIALY LETHAL. DO NOT RUN ENGINE IN AN ENCLOSED AREA. PERFORM WORK IN A WELL- Figure 7—Engine Compartment Heater VENTILATED AREA. Piping 3. Fill cooling system completely, including surge tank with coolant.

4. Run engine until coolant hoses are warm to touch.

370-8 A3 Heaters and Defrosters

5. Open the heater hose supply line gate valve or unclamp supply line hose.

6. Check water pump to make sure it is running. Note Be sure to use a large container for draining coolant. 7. Run engine between 2,000 and 3,000 rpm.

8. Loosen bleeder valve located in heater hose line, see Figure 7—Engine Compartment Heater Piping. Note Coolant refill is necessary during bleeding. 9. Bleed air and coolant through bleeder valve until air is eliminated from heater system. Figure 8—Heater Cutoff Valve 10. Stop bleeding when continuous stream of Troubleshooting coolant is discharged. • Hoses 11. Open gate valve in heater hose return line after all air is purged. 1. Check all water hoses for kinks that prevent water flow. 12. Run engine between 2,000 and 3,000 rpm until thermostats open. 2. Inspect hoses for hardening of rubber, or cracks.

13. Refill cooling system including radiator surge • Coils tank. The heater coil can be accessed through the right Cutoff Valves front inside panel.

• Underseat heaters can be accessed by removing passenger cushions.

• Motors Do not operate with valve 3 closed and other valves open due to high pressure build up. 1. Inspect wheels and fans for obstructions or damage by running each fan separately. • Valves are used to isolate the heater system

from the engine to control leaks, see Figure 2. Replace damaged wheel or fans to prevent 8—Heater Cutoff Valve. vibration damage to other connecting equipment.

• Switches

1. Inspect for loose wiring.

2. Inspect for bad or loose connections.

370-9 A3 Heaters and Defrosters

• Panels and housings Troubleshooting • Electrical Schematic 1. Inspect fasteners that connect and retain structural and access panels. • Kysor™ Heater (Driver’s Heater), see Schematic 1—Kysor™ Heater. • Hose • Coolant Level Sender, see Schematic 2— 1. Repaired damaged hose by cutting out the bad Coolant Level Sender. section and installing a (4) inch brass tube and hose clamps. • Coolant Temperature Sender, see Schematic 2—Coolant Temperature Sender. 2. Replace full length of hose due to aging or heavy damage. • Removal of fan • Heater hose clamp service 1. Use a 3/32 inch Allen wrench, set screw is behind the fan. Heater hose clamps are located at the under seat heater coil, behind the access door in the heater hose 2. Remove the rear half of the fan guard by covering, immediately forward of the left front removing (2) nuts and washers on each side of wheel housing. Another location is under the floor, center point. near the right front and driver’s heater.

1. Tighten heater hose clamps after first 1,000 hours of service.

2. Torque hose clamps to 45 inch-pounds as new and 34 inch-pounds for a re-torque.

DO NOT OPERATE DEFROSTER FAN WITHOUT THEW FAN GUARD PROPERLY INSTALLED.

• Defroster fan cleaning

• Remove front half of fan guard by gently separating plastic tabs with a screwdriver. Be cautious of cold temperature that may make tabs brittle.

370-10 A3 Heaters and Defrosters

Schematic 1—Kysor Heater

370-11 A3 Heaters and Defrosters

Schematic 2—Coolant Level Sender

370-12 A3 Heaters and Defrosters

Schematic 3—Coolant Temperature Sender

370-13 A3 Heaters and Defrosters

Defroster Fan Locations Option 0525 All American with deluxe door control and standard manual control. The fan is mounted on the door control bracket. With power door control the fan is mounted on the dash, cover. 0530 One (1) fan is installed per conditions outlined in Option 0525 for the left-hand fan. The other fan is mounted on the dash cover. 0532 The fan is located on the upper inner panel in the center. 0535 The fan is located on the upper inner panel 6 inches to the left of center. 0541 Defroster fan is located on the dash cover. Table 1—Defroster Fan Location by Option

Heater Cutoff Valve Location Engine Location Engine Cummins 8.3T Location Caterpillar 3116 Valve Valve 1 On heater 1 On heater 2 Behind alternator 2 Below turbocharger 3 Behind remote 3 Behind remote transmission cooler transmission cooler Table 2—Heater Cutoff Valve Location

Heater Connections Water Capacity Table Option Description Capacity (Quarts) Standard 90 FC front heater 3.45 1230 12 Driver’s heater 0.25 1325 50 Front under seat heater 0.75 1330 50 Rear under seat heater 0.75 1332 50 Rear RH under seat heater 0.75 1336 80 Front under seat heater 1.32 1342 80 Rear under seat heater 1.32 1 Foot of connecting line 0.17 Table 3—Heater Water Capacity

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