40 AGR 055A through 100A IOMM AGR
11. Check on the Global UNT controller between terminals marked 24Vac and common for 24Vac
control voltage. Green light on Global UNT controller should be flashing.
Start-Up
There should be adequate building load (25% of unit capacity minimum) to properly check the
operation of the chiller refrigerant circuits.
Be prepared to record all operating parameters required by the “Compressorized Equipment
Warranty Form”. Return this information within 10 working days to McQuay International as
instructed on the form to obtain full warranty benefits.
1. Verify chilled water flow.
2. Verify remote start / stop or time clock has requested the chiller to start.
3. Set the chilled water setpoint to required temperature. (The system water temperature must be
greater than the total of the leaving water temperature setpoint plus 1/2 the control band before
the Global UNT controller will stage on cooling.)
4. Set the control band to 4°F as a starting point.
5. Put both circuit switches to the AUTO position.
6. Put switch S1 to AUTO position.
7. There will be a delay of 2 minutes after closing S1. The time delay is due to the compressor
inherent motor protection. This may allow more than one compressor to start after this time
period. This should only occur on initial start-up or when power to the chiller has been turned
off and back on. The panel Alarm Light will turn off.
8. After operating for a period of time and unit has become stable, check the following:
§ Compressor oil level.
§ Refrigerant sight glass for flashing.
§ Rotation of condenser fans.
Shutdown
Temporary
1. Put both circuit switches to Pumpdown and Stop.
2. After compressors have stopped, put System Switch (S1) to Emergency Stop.
3. Turn off chilled water pump. Chilled water pump to operate during pumpdown.
To start the chiller after a temporary shutdown follow the start up instructions.
Extended
1. Front seat both condenser liquid line service valves.
2. Put both circuit switches in Pumpdown and Stop position.
3. After the compressors have stopped, put System Switch (S1) in Emergency Stop position.
4. Front seat both refrigerant circuit discharge valves.
5. If chilled water system is not drained, maintain power to the evaporator heater to prevent
freezing. Maintain heat tracing on the chilled water lines.
6. Drain evaporator and water piping to prevent freezing.
7. If electrical power is on to unit, the compressor crankcase heaters will keep the liquid
refrigerant out of the compressor oil. This will minimize start up time when putting the unit
back into service. The evaporator heater will be able to function.
8. If electrical power is off, make provisions to power the evaporator heater (if chilled water
system is not drained). Tag all opened electrical disconnect switches to warm against startup
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