Microtek MHP1-HD Installation Manual download pdf (Page 41)

OMRCPMICRO 41

Start-up after temporary shutdown—Move the Circuit #1 and Circuit #2 pumpdown switches to the Auto

position. If the controller is calling for cooling or heating, the compressors will start and the unit will stage up

as required. If cooling or heating is not requested, the circuits may pump down and the compressors will stop.

Extended shutdown

CAUTION

It is the operator's responsibility to provide protection against water circuit freezing on ALR

units. All water must be drained from the evaporator and associated piping and power for

the cooler heating cable should be applied via separate disconnect if freezing ambient

conditions are expected.

1. Close the manual liquid line shutoff valves. Move the circuit #1 and Circuit #2 pumpdown switches to the

"Pumpdown and Stop" position. Each operating circuit will pumpdown and the compressors will stop. In

this condition, the compressors will remain off and no additional pumpdown will occur even if the

evaporator pressure rises above the LPCutIn setpoint.

2. After both circuits have been pumped down, open the Remote Stop Switch and the controller will stop the

chilled water pump.

3. Move the System Switch to the " Emergency Stop" position. Turn off main power to the unit and to the

chilled water pump.

4. Close the compressor suction and discharge valves and the oil equalization line valve.

5. Tag all opened electrical disconnect switches to warn against start-up before opening the compressor

suction, discharge and liquid line valves.

6. On ALR units, drain all water from the unit evaporator and chilled water piping and leave power applied to

the cooler heating cable via separate disconnect if the unit will be exposed to freezing ambient

temperatures.

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Microtek MHP1-HD Installation Manual Page 41