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HIGH PRESSURE SWITCH The WA381, WA484, WA491 and WA602 models are supplied with a remote reset high pressure switch. If tripped, this pressure switch may be reset by turning the thermostat off then back on again. THREE PHASE SCROLL COMPRESSOR START UP INFORMATION Scroll compressors, like several other types of compressors, will only compress in one rotational direction. Direction of rotation is not an issue with single phase compressors since they will always start and run in the proper direction. However, three phase compressors will rotate in either direction depending upon phasing of the power. Since there is a 50-50 chance of connecting power in such a way as to cause rotation in the reverse direction, verification of proper rotation must be made. Verification of proper rotation direction is made by observing that suction pressure drops and discharge pressure rises when the compressor is energized. Reverse rotation also results in an elevated sound level over that with correct rotation, as well as, substantially reduced current draw compared to tabulated values. Verification of proper rotation must be made at the time the equipment is put into service. If improper rotation is corrected at this time there will be no negative impact on the durability of the compressor. However, reverse operation for over one hour may have a negative impact on the bearing due to oil pump out. NOTE: If compressor is allowed to run in reverse rotation for several minutes, the compressor’s internal protector will trip. All three phase ZR compressors are wired identically internally. As a result, once the correct phasing is determined for a specific system or installation, connecting properly phased power leads to the same Fusite terminal should maintain proper rotation direction. The direction of rotation of the compressor may be changed by reversing any two line connections to the unit. PHASE MONITOR All units with three phase scroll compressors are equipped with a 3 phase line monitor to prevent compressor damage due to phase reversal. The phase monitor in this unit is equipped with two LEDs. If the Y signal is present at the phase monitor and phases are correct the green LED will light. If phases are reversed, the red fault LED will be lit and compressor operation is inhibited. If a fault condition occurs, reverse two of the supply leads to the unit. Do not reverse any of the unit factory wires as damage may occur. CONDENSER FAN OPERATION The condenser fan motor on 230/208 volt, one and three phase, 60 HZ units is a two speed motor that comes factory wired on high speed for peak performance. If ambient conditions permit, it can be reconnected to low speed (red wire) for lower sound level. See wiring diagram. 50 HZ models must have fan wired on low speed. These models are factory wired on low speed. 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. Check all power fuses or circuit breakers to be sure they are the correct rating. 4. Periodic cleaning of the outdoor coil to permit full and unrestricted airflow circulation is essential. Manual 2100-398 Page 14 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 of constant air circulation. On all 230 volt units there is a one minute off delay on the blower motor. 460 volt models do not have an off delay. On a call for heating, circuit R-W1 make at the thermostat pulling in heat contact for the strip heat and blower operation. On a call for second stage heat, R-W2 makes bringing on second heat contactor, if so equipped. COMPRESSOR CONTROL MODULE The compressor control module is standard on the WA391, WA484, WA491and WA602 models covered by this manual and is optional on the WA423 model. The compressor control is an anti-short cycle/lockout timer with high and low pressure switch monitoring and alarm relay output. Adjustable Delay On Make And Break Timer On initial power up or any time power is interrupted to the unit the delay on make period begins which will be 2 minutes plus 10% of the delay on break setting. When the delay on make is complete and the high pressure switch (and low pressure switch if employed) is closed, the compressor contactor is energized. Upon shutdown the delay or break timer starts and prevents restart until the delay on break and delay on make periods have expired. During routine operation of the unit with no power in...

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