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Stage 2 has an adjustable anticipator for the W2 connection and fixed for the W3 connection. Both the W2 and W3 circuits are controlled by the stage 2 bulb. The only heat anticipator that needs to be checked is stage 2 and it should be set to match the load carried by the W2 circuit. The normal factory wiring provides for only one electric heat contactor to be controlled by W2, and the anticipator should be set at .40A. If special field wiring is done, it is best to actually measure the load but a good rule is .40A for each heat contactor controlled by W2. THERMOSTAT INDICATOR LAMPS The green lamp marked “Check” will come on if there is any problem that prevents the compressor from running when it is supposed to be. COMPRESSOR MALFUNCTION LIGHT Actuation of the green “Check” lamp is accomplished by a relay output from the heat pump control board which is factory installed. Any condition such as loss of charge, high head pressure, etc., that will prevent compressor from operating will cause green lamp to activate. This is a signal to the operator of the equipment to place system in emergency heat position. TABLE 4 WALL THERMOSTAT AND SUBBASE COMBINATIONS Thermostat Subbase Predominant Features 8403-045 (T841A1761) ---heat; Mercury bulbcool; 2 stg.1 stg. Manual changeover 8403-017 (T874R1129) 8404-009 (Q674L1181) heat; Mercury bulbcool; 2 stg.2 stg. Manual changeover 8403-018 (T874N1024) 8404-010 (Q674F1261) heat; Mercury bulbcool; 2 stg.2 stg. Auto or Manual changeover 8403-042 (T8511G1070) ---heatcool; 2 stg.1 stg. Electronic Non-Programmable Auto or Manual changeover 8403-049 (1F93-380) ---heatcool; 3 stg.2 stg. Programmable Electronic Auto or Manual changeover IMPORTANT NOTE: The thermostat and subbase combinations shown above incorporate the following features: Man-Auto fan switch, Off-Heat-Cool-Em. Heat Switch, and two (2) indicator lamps; one for emergency heat and one for compressor malfunction. Manual 2100-373 Page 12 START UP IMPORTANT INSTALLER NOTE For improved start up performance, wash the indoor coil with a dish detergent. CRANKCASE HEATERS WH241 units are provided with compressor crankcase heat. These models have an insertion well-type heater located in the lower section of the compressor housing. This is a self-regulating type heater that draws only enough power to maintain the compressor at a safe temperature. Some form of crankcase heat is essential to prevent liquid refrigerant from migrating to the compressor causing oil pump out on compressor start up and possible valve failure due to compressing a liquid. The decal in Figure 9 is affixed to all outdoor units detailing start up procedure. This is very important. Please read carefully. HEATING – a 24V solenoid coil on reversing valve controls heating cycle operation. Two thermostat options, one allowing “Auto” changeover from cycle to cycle, and the other constantly energizing solenoid coil during heating season and thus eliminating pressure equalization noise except during defrost, are to be used. On “Auto” option, a circuit is completed from R-W1 and R-Y on each heating “ON” cycle energizing reversing valve solenoid and pulling in compressor contactor starting compressor and outdoor motor. R-G also make starting indoor blower motor. Heat Pump heating cycle now in operation. The second option has no “Auto” changeover position, but instead energizes the reversing valve solenoid constantly whenever the system switch on subbase is placed in “Heat” position, the “B” terminal being constantly energized from R. A thermostat demand for heat completes R-Y circuit pulling in compressor contactor starting compressor and outdoor motor. R-G also make starting indoor blower motor. FIGURE 9 SERVICE HINTS 1. Caution homeowner to maintain clean air filters at all times. Also, not to needlessly close off supply and return air registers. This reduces air flow through the system which shortens equipment service life as well as increasing operating costs. 2. Switching to heating cycle at 75° F or higher outside temperature may cause a nuisance trip of the remote reset high pressure switch. Turn thermostat off, then on, to reset the high pressure switch.. 3. The heat pump wall thermostats perform multiple functions. Be sure that all function switches are correctly set for the desired operating mode before trying to diagnose any reported service problems. 4. Check all power fuses or circuit breakers to be sure they are the correct rating. 5. Periodic cleaning of the outdoor coil to permit full and unrestricted airflow circulation is essential. SEQUENCE OF OPERATION COOLING – Circuit R-Y makes at thermostat pulling in compressor contactor, starting the compressor and outdoor motor. The G (indoor motor) circuit is automatically completed on any call for cooling operation or can be energized by manual fan switch on subbase for constant air circulation. IMPORTANT THESE PROCEDURES MUST BE FOLLOWED AT INITIAL START UP AND AT ANY TIME POWER HAS BEEN REMOVED FOR 12 H...

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