SERVICE MANUAL FOR 7535, 8534, 8535 SERIES HEAT PUMPS

1 SERVICE MANUAL . FOR. 7535, 8534, 8535 SERIES . HEAT PUMPS . TABLE OF CONTENTS. I. Warnings .. 3. II. Unit Specifications .. 4. III. Heat Pump Operation With 7530-716 Or 8530-715 Standard Ceiling Assemblies .. 5. IV. Wall Thermostat Specifications And Heat Pump Operations With 7530-736 Or 8530-735 Ducted Plenums .. 7. V. Basic Components And Their Functions .. 9. VI. The Heat Pump Refrigeration Cycle .. 11. VII. General Electrical Operational Information .. 12. VIII. SERVICE Problems And Possible Solutions .. 13. IX. Individual Electrical Component Checkouts .. 14. X. Wiring Diagrams .. 20. I. WARNINGS. IMPORTANT NOTICE WARNING - SHOCK HAZARD. These instructions are for the use of qualified individuals To prevent the possibility of severe personal injury or specially trained and experienced in installation of this type equipment damage due to electrical shock, always be sure the equipment and related system components.

2 Electrical power to the appliance is disconnected. Installation and SERVICE personnel are required by some states CAREFULLY FOLLOW ALL INSTRUCTIONS AND. to be licensed. PERSONS NOT QUALIFIED SHALL NOT WARNINGS IN THIS BOOKLET TO AVOID DAMAGE TO. SERVICE THIS EQUIPMENT. THE EQUIPMENT, PERSONAL INJURY OR FIRE. WARNING NOTE. Improper installation may damage equipment, can create a The words Shall or Must indicate a hazard and will void the warranty. requirement which is essential to satisfactory and safe product performance. The use of components not tested in combination with these units will void the warranty, may make the equipment in The words Should or May indicate a violation of state codes, may create a hazard and may ruin the recommendation which is not essential equipment. and not required, but which may be useful or helpful. UNIT MODEL NUMBER BREAKDOWN. 3. II. UNIT SPECIFICATIONS.

3 Cooling Capacity 15,000 (Nominal BTUH). Heating Capacity In Heat Pump Mode 12,700 (Nominal BTUH at 47 F). Heating Capacity Of Electric Heat Strip 5,600 BTUH. Electrical Rating 115 VAC, 60 HZ, 1 Phase Compressor Cooling Full Load Fan Motor Amps At Low High Total Standard Condition Feature Heating Equipment Amps Running Watts (Cooling) Standard Condition 1710. (80 F. DB/67 F. WB Indoor, 95 F. DB Outdoor at VAC). Running Watts (Cooling) Maximum Condition 2150. (95 F. DB/71 F. WB Indoor, 115 F. DB Outdoor At VAC). Running Watts (Heating) 47 F. Outdoor Temperature 1675. Compressor Locked Rotor Amps Compressor Ohm Ratings (Approx.) (C-S) (C-R) .5. C = Common, S = Start, R = Run Thermostat Temperature Range Cooling 55 F Heating 90 F. Metering Device Capillary Tube Refrigerant Charge oz. Evaporator Air Delivery 340 CFM - High Installed Weight 110 lbs. Use time delay fuse or circuit breaker ( Type ) rated at 20 amps.

4 Supply wires 12 AWG minimum (copper). 4. III. HEAT PUMP OPERATION WITH 7530-716 OR 8530-715. STANDARD CEILING ASSEMBLIES. If your RV air conditioner is operated from the control panel located in the ceiling assembly, then there are three controls on the ceiling assembly that help you control the air conditioner. They are as follows: A. The Selector Switch The selector switch determines which mode of operation the heat pump will be in. By FIGURE 1. rotating the selector switch, the operator can obtain any system function desired. System functions vary depending upon options of both the roof top unit and ceiling assembly. Figures 1 and 2 show selector switch location and available functions. The Operation section explains the operational characteristics of each mode of operation. B. The Thermostat (Temperature Control) The thermostat regulates the ON and OFF . temperature setting at which the compressor will operate (See Figures 1 and 2).

5 C. Louvers The louvers are located at both ends of the CEILING ASSEMBLY STICKER. ceiling assembly shroud and are used in directing the discharge air from the unit. FIGURE 2. OPERATION. I. For Cooling Operation II. Operation During Cooler Nights (Cooling Operation). A. Turn the selector switch to the LOW COOL or HIGH COOL position. It is important, when the outdoor temperature drops in the evening or during the night to below 75 F, that the thermostat B. Rotate the thermostat (temperature control) to the (temperature control) be set at a midpoint between Warmer . position that is the most comfortable to you. The and Cooler . If the setting is at cooler , the cooler thermostat will turn the compressor on when the (evaporator) coil may become iced-up and stop cooling. temperature of the air entering the air conditioner During the day, when the temperatures have risen above 75 F, rises a few degrees above the setting you have reset the thermostat switch to the desired setting.

6 Selected. When the temperature of the air entering the air conditioner drops below the selected setting, NOTE. the thermostat will turn the compressor off. The air conditioner, while in the cooling mode, will continue Should icing-up occur, it is necessary to let the cooling to cycle the compressor on and off in the above (evaporator) coil defrost before normal cooling operation is mentioned fashion until the selector switch is turned resumed. During this time, operate the unit in the HIGH. to another mode of operation. FAN position with the system at maximum air flow. When increased or full air flow is observed, the cooling coil should C. Position the louvers to the desired direction the be clear of ice. discharge air is to flow. III. Short Cycling When an air conditioner is in operation, its compressor circulates refrigerant under high pressure. Once off, it will take two to three minutes for this high pressure to equalize.

7 5. The air conditioning compressor is unable to start against high the vehicle for more efficient circulation and faster pressure. Therefore, once the air conditioner is turned off, it is warm-up. Although the air temperature is lower with important to leave it off for two to three minutes before the louvers fully opened, the heating capacity is still restarting. the same. Short cycling the compressor (or starting it before pressures NOTE. have equalized), will in some instances, kick the circuit breaker or overload. The heat pump will operate on reverse refrigerant cycle while heating at outdoor IV. For Heating Operation temperatures above approximately 40 degrees F. When the outdoor temperature is below A. Turn the selector switch to the HIGH HEAT approximately 40 degrees F, the position. At HIGH HEAT , the fan operates on high heat pump compressor will shut down to speed with heat output at maximum.

8 Prevent outdoor coil freeze-up. At this time, the auxiliary electric resistance B. Rotate the thermostat (temperature control) switch to heater will be utilized to take the chill out the position that is the most comfortable to you. The of the indoor air. The electric resistance thermostat will turn the compressor/heater on when heater is not a substitute for a furnace at the temperature of the air entering the unit drops these low outdoor temperatures. below this setting a few degrees, and automatically turns off when the temperature of the air entering the V. For Air Circulation Only unit rises a few degrees above this setting. The compressor/heater will continue to cycle on and off in A. Turn the selector switch to LOW FAN or for this fashion until the selector switch is turned to maximum air flow, to HIGH FAN . another mode of operation. D. Position the louvers to the desired direction the C.

9 Position the louvers to the desired direction the discharge air is to flow. discharge air is to flow. NOTE. Discharge air temperature can be controlled to some extent by opening or closing the louvers. When the selector switch is in LOW. FAN or HIGH FAN position, the When the louvers are closed, the warmest localized blower motor will operate continuously. discharge air is achieved. Fully opened louvers will throw the warm discharge air to the back and front of 6. IV. WALL THERMOSTAT SPECIFICATIONS AND. HEAT PUMP OPERATIONS WITH. 7530-736 or 8530-735 DUCTED PLENUMS. WALL THERMOSTAT SPECIFICATIONS. SET TEMP. RANGE: 55 TO 90 F. ACCURACY: 2% OF SET TEMPERATURE. SAMPLING RATE: CONTINUOUS. POWER SOURCE: 9 TO 15 VDC UNREGULATED, UNFILTERED. OPERATING TEMPERATURE: -10 TO +55 C. CONTROL MODE: 1 STAGE COOL - ON/OFF CONTROL WITH 3 MINUTE DELAY. BETWEEN CYCLES. OUTPUT LOAD: 40 mA MINIMUM TO AMP MAXIMUM TOTAL LOAD.

10 SAFEGUARDS: * 15 KV TO EXPOSED PLASTIC PARTS. * REVERSE POLARITY PROTECTION ON R+ TERMINAL. * SPIKE PROTECTION TO 400 VDC ON R+ TERMINAL. * CONFORMAL COATING ON BOARD PROTECTION FROM MOISTURE. SUB-BASE SPECIFICATIONS. 1. 7330*3351 THERMOSTAT MUST ASSEMBLE SECURELY TO THE SUB-BASE. 2. WIRES ARE 18 GA. STRANDED COPPER WITH 1/64 MIN. THICK AT INSULATION EXTENDING FROM BACK OF PART. 7 INCHES, ENDS STRIPPED BACK 1/2" AND TERMINATED WITH WIRE NUTS. 3. SNAP DISC SWITCH CLOSES AT 45 5 F AND OPENS AT 60 3 F. Sub-base This thermostat is equipped with a replaceable 2 amp fuse located on the back of the thermostat body. Thermostat Body 7. OPERATION. The charts below show the system functions. After the entire air conditioning system (and furnace system) is installed, check each position function. All cooling functions controlling to setpoint have a short cycle protection time delay of 3 minutes.