Sterling GP Series Refrigerator User Manual


 
GP Series Portable Chillers Chapter 2: Functional Description 9 of 44
Refrigeration Features
HFC-410a refrigerant
Electronic hot gas bypass capacity control
High refrigerant pressure cutout switches
Suction and discharge pressure transducers.
High pressure spring actuated relief valve
Multiple refrigeration access ports
Liquid line shut-off ball valves
Filter-dryer
Sight glass
Externally equalized thermal expansion valve
Liquid line solenoid
Compressor crankcase heater
Controller Features
Off-the-shelf microprocessor-based PID auto-tuning controller with To Process, From
Process and Set Point readout
Time delay for proof of water flow/pressure (models w/pump only)
Low refrigerant pressure time delay for low ambient start-up on remote air-cooled and
air-cooled chillers with the variable-speed fan option.
4 line x 20 character display with status, alarm, and service screens
Other Features
One year labor warranty and one year compressor warranty
Two year parts warranty
Two year limited controller warranty
2-4 Safety Devices and Interlocks
Caution! Protect the system from freezing with glycol 20ºF below the leaving water
temperature set point. Condensation may form inside the pump tank and dilute
the mixture, therefore the freezing point should be verified periodically. See
Figure 6 on page 18 for the correct mixture.
Crankcase Heater
5 hp through 15 hp portable chillers have a crankcase heater. It is wired through the control
transformer that operates continuously whenever power is applied to the chiller.
Caution! Energize the crankcase heater for at least 24 hours before initial startup to
drive dissolved refrigerant from the compressor oil. Failure to do so will
damage the compressor.