START UP AND OPERATION
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
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*3 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 terminals should maintain proper rotation direction.
The direction of rotation of the motor may be changed by reversing any two line connections to the unit.
SEQUENCE OF OPERATION
COOLING – Circuit
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
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
DEFROST CYCLE
The defrost cycle is controlled by temperature and time on the solid state heat pump control.
When the outdoor temperature is in the lower 40° F temperature range or colder, the outdoor coil temperature is 32°F or below. This temperature is sensed by the coil sensor mounted near the bottom of the outdoor coil. Once the coil temperature reaches 32°F or below, the coil sensor sends a signal to the control logic of the heat pump control and defrost timer will start.
After 60 (90 or 30) minutes at 32°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
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.
There is an initial defrost (sen jmp) jumper 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.
START UP NOTES
For improved start up performance, wash the indoor coil with dishwasher detergent
Manual
