6
PFS 155C - 315C
OM 135
Temporary Shutdown
CAUTION
To prevent evaporator freeze-up, continue chilled water flow to the unit for 5 minutes after the
compressors have stopped.
If all power is turned off to the unit the compressor heaters will become inoperable. Once power is
resumed to the unit it is important that the compressor heaters are energized a minimum of 12 hours.
Failure to do so could damage the compressors due to excessive accumulation of liquid in the
compressor.
CAUTION
The unit must not be cycled off by using the evaporator pump or the disconnect switch. A
start / stop input is required.
Start-up After Temporary Shutdown
1.
Ensure compressor heaters have been energized for at least 12 hours
2.
Start the chilled water pump.
3.
Place unit control switch in “auto” position.
4.
Observe unit operation until the system has stabilized.
5.
Record unit operating conditions.
Extended Shutdown
1.
Place control panel switches in "stop" position.
2.
After compressors have shut down and electronic expansion valves have closed, turn off chilled
water pump.
3.
Turn off all power to the unit and to the chilled water and condenser water pumps.
4.
Tag all opened disconnect switches to warn against accidental startup before completing
compressor checks.
5.
If the unit is shut down during winter and glycol is not used in the system, drain all water from
unit evaporator, condenser and all water piping . Do not leave the vessels or piping open to the
atmosphere over the shutdown period.
Start-up After Extended Shutdown
1.
Inspect all equipment to ensure a satisfactory operating condition.
2.
Clean cooling tower. Remove all debris that has collected near the tower.
3.
Place compressor suction and discharge valves in the fully open position. Always replace valve
seal caps.
4.
Open manual liquid line shutoff valves.
5.
Make certain that circuit breakers are in the "off" position.
6.
Make certain control panel rocker switches are in "stop" position.
7.
Place main power and control circuit disconnects in ”on” position.
8.
Allow the crankcase heaters to operate for a least 12 hours.
