McQuay AGZ 035A, Installation, Operation And Maintenance Manual

Page: 31 / 96

IOMM AGZ-3 AGZ 035A through 065A 31
Electrical Check Out
CAUTION
Electrical power must be applied to the compressor crankcase heaters 24
hours before starting unit to drive off refrigerant from the oil.
1. Open all electrical disconnects and check all power wiring connections. Start at the power block
and check all connections through all components to and including the compressor terminals.
These should be checked again after 3 months of operation and at least yearly thereafter.
2. Check all control wiring by pulling on the wire at the spade connections and tighten all screw
connections. Check plug-in relays for proper seating and to insure retaining clips are installed.
3. Put System Switch (S1) to the Emergency Stop position.
4. Put both circuit #1 & #2 switches to the Pumpdown and Stop position.
5. Apply power to the unit. The panel Alarm Light will stay on until S1 is closed. Ignore the Alarm
Light for the check out period. If you have the optional Alarm Bell, you may wish to disconnect
it.
6. Check at the power block or disconnect for the proper voltage and proper voltage between
phases.
7. Check for 120Vac at the optional control transformer and at TB-2 terminal #1 and the neutral
block (NB).
8. Check between TB-2 terminal #7 and NB for 120Vac supply for transformer #2.
9. Check between TB-2 terminal #2 and NB for 120Vac control voltage. This supplies the
compressor crank case heaters.
10. Check between TB-3 terminal #17 and #27 for 24Vac control voltage.
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.