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Resumen del manual
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 HOURS OR LONGER. TO PREVENT COMPRESSOR DAMAGE WHICH MAY RESULT FROM THE PRESENCE OF LIQUID REFRIGERANT IN THE COMPRESSOR CRANKCASE: 1. MAKE CERTAIN THE ROOM THERMOSTAT IS IN THE “OFF” POSITION. (THE COMPRESSOR IS NOT TO OPERATE.) 2. APPLY POWER BY CLOSING THE SYSTEM DISCONNECT SWITCH. THIS ENERGIZES THE COMPRESSOR HEATER WHICH EVAPORATES THE LIQUID REFRIGERANT IN THE CRANKCASE. 3. ALLOW 4 HOURS OR 60 MINUTES PER POUND OF REFRIGERANT IN THE SYSTEM AS NOTED ON THE UNIT RATING PLATE, WHICHEVER IS GREATER. 4. AFTER PROPERLY ELAPSED TIME THE THERMOSTAT MAY BE SET TO OPERATE THE COMPRESSOR. 5. EXCEPT AS REQUIRED FOR SAFETY WHILE SERVICING — DO NOT OPEN SYSTEM DISCONNECT SWITCH. 7961-061 Manual 2100-373 Page 13 PRESSURE SERVICE PORTS High and low pressure service ports are installed on all units so that the system operating pressures can be observed. Pressure curves can be found later in the manual covering all models on both cooling and heating cycles. It is imperative to match the correct pressure curve to the unit by model number. DEFROST CYCLE The defrost cycle is controlled by temperature and time on the solid state heat pump control. See Figure 10. When the outdoor temperature is in the lower 40° F temperature range or colder, the outdoor coil temperature is 32° F or below. This coil temperature is sensed by the coil sensor mounted near the bottom of the outdoor coil. Once coil temperature reaches 30° F or below, the coil sends a signal to the control logic of the heat pump control and the defrost timer will start. After 30 minutes at 30° F or below, the heat pump control will place the system in the defrost mode. During the defrost mode, the refrigerant cycle switches back to the cooling cycle, the outdoor motor stops, electric heaters are energized, and hot gas passing through the outdoor coil melts any accumulated frost. When the temperature rises to approximately 57° F, the coil sensor will send a signal to the heat pump control which will return the system to heating operations automatically. If some abnormal or temporary condition such as a high wind causes the heat pump to have a prolonged defrost cycle, the heat pump control will restore the system to heating operation automatically after 10 minutes. There are three settings on the heat pump control – 30 minute, 60 minute, and 90 minute. Models are shipped wired on the 30 minute setting for greatest operating FIGURE 10 DEFROST CONTROL BOARD MIS-1174 economy. If special circumstances require a change to another time, remove wire connected to terminal 30 and reconnect to desired terminal. Refer to Figure 10. The manufucturer’s recommendation is for 3 minute defrost cycles. There is a cycle speed up jumper on the control. This can be used to reduce the time between defrost cycle operation without waiting for time to elapse. Use a small screwdr4iver or other metallic object, or another 1/4 inch QC, to short between the SPEEDUP terminals to accedlerate the HPC timer and initiate defrost. Be careful not to touch any other terminals with the instrument used to short the SPEEDUP terminals. It may take up to 10 seconds with the SPEEDUP terminals shorted for the speedup to be completed and the defrost cycle to start. As soon as the defrost cycle kicks in remove the shorting instrument from the SPEEDUP terminals. Otherwise the timing will remain accelerated and run through the 1 minute maximum defrost length sequence in a matter of seconds and will automatically terminate the defrost sequence. There is an initiate defrost jumper (sen jump) on the control that can be used at any outdoor ambient during the heating cycle to simulate a 0° coil temperature. This can be used to check defrost operation of the unit without waiting for the outdoor ambient to fall into the defrost region. By placing a jumper across the SEN JMP terminals (a 1/ 4 inch QC terminal works best) the defrost sensor mounted on the outdoor coil is shunted out and will activate the timing circuit. This permits the defrost cycle to be checked out in warmer weather conditions without the outdoor temperature having to fall into the de...
Otros modelos de este manual:Eléctrico - WH242 (245.73 kb)