Electrical Installation; Sequence Of Operation - G&D VERTICAL AIR Series Installation Manual & User Manual

INSTALLATION GUIDE • USER MANUAL

ELECTRICAL INSTALLATION

GENERAL RECOMMENDATIONS
All wiring must comply with local codes and the National Electric Code. Minimum circuit ampacities and other unit
electrical data are on the unit nameplate. Specific electrical schematics and connection diagrams are shipped with
the unit.
WARNING: HAZARDOUS VOLTAGE!
Disconnect all electric power, including remote disconnects before servicing. Follow proper lock- out/tagout
procedures to ensure the power cannot be inadvertently energized. Failure to disconnect power before servicing
could result in death or serious injury.
CAUTION: USE COPPER CONDUCTORS ONLY!
Unit terminals are not designed to accept other types of conductors. Failure to use copper conductors may result in
equipment damage.
Important! Do not allow conduit to interfere with other components, structural members or equipment. Control
voltage wiring in conduit must be separate from conduit carrying low voltage (<30V) wiring. To prevent control
malfunctions, do not run low voltage wiring (<30V) in conduit with conductors carrying more than 30 volts.

SEQUENCE OF OPERATION

1. Chiller supply and return ball valves should always be open during normal operation.
2. Fluid bypass valve is factory set at 20 PSI valve design to allow minimum flow across heat exchanger when
process is not calling for cooling.
3. Pump circulates at all times when panel door switch is in the Run position.
4. Compressor control circuit is energized when pump is running.
5. If pump fails or flow fails compressor control circuit will de-energize.
6. Programmable logic controller (PLC) energizes Electronic Expansion Valve (EEV) based on leaving fluid
temperature.
7. The controller will energize the compressor starter while monitoring system pressures and flow.
8. If all parameters remain in a safe range, the compressor will continue to run until the thermostatic logic detects
that it is no longer needed. At that point, the EEV will close, the compressor will pump down and stop.
10. Door switch will pump down compressor then turn off pump if switch is shut off during compressor run cycle.
11. Line voltage power should be left on to main terminal block at all times to keep crank case heater energized
during extended off cycles.
G&D CHILLERS, INC. • GD-VA-R2022C
VERTICAL AIR SERIES
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