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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.
9. T
he 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.
MAINTENANCE
Please contact G&D Technical Support
if you have any questions or concerns regarding the performance, operation,
or maintenance of your chiller:
800-555-0973
•
Refer to the separate G&D Chillers Preventive Maintenance Checklist for a complete list of maintenance tasks.
•
Contract a licensed refrigeration technician to evaluate the chiller refrigeration circuit(s) regularly. These
checkups should occur annually at a minimum. Every 3-6 months is recommended.
The following tasks can be performed without the need for specialized equipment or training:
•
Check glycol level and glycol/water ratio monthly. Use glycol refractometer to confirm 35% glycol mixture.
•
Check compressor oil in sight glass at bottom of compressor monthly. Inspect for any oil leaks.
•
Verify pump function quarterly. Confirm glycol supply pressure. Listen for abnormal sounds from the pump.
•
Verify thermostat function quarterly. Check displayed temperature against a thermometer measurement.
•
Condenser should be cleaned at least every 6 months for proper operation and efficiency. Use a garden hose
and spray at an angle downward. If in a dirty environment, cleaning may be needed more often.
•
Lubricate fan motors every 12 months.
•
See warning below. With the service disconnect in the OFF position (no power to the chiller), inspect control
panel contacts on compressor and pump contactors. Contact an electrician if replacements are needed.
WARNING: DO NOT ATTEMPT TO SERVICE ELECTRICAL COMPONENTS OR MAKE ADJUSTMENTS IN ELECTRICAL
PANEL WITHOUT PROPER TRAINING AND IMPLEMENTATION OF LOCKOUT/TAG-OUT SAFETY PROCEDURES