Sterling GP Series Safety Devices and Interlocks, Refrigeration Features, Controller Features

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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.

GP Series Portable Chillers

Chapter 2: Functional Description

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Contents GP Series Portable Chillers Shipping Information Table of Contents Maintenance Safety How to Use This ManualSafety Symbols Used in this Manual Responsibility Models Covered in This Manual Functional DescriptionGeneral Description Chilled Water CircuitStandard Features Mechanical FeaturesElectrical Features Refrigeration Features Safety Devices and InterlocksController Features Other FeaturesFlow Switch Optional FeaturesHigh Pressure Cutout Remote Start/Stop InterlockMounting Features Optional Pump Amperages Voltage Construction Full Load Amps Installation UncratingElectrical Connections Bypass Valve Considerations Process Water ConnectionsGalvanic Corrosion Considerations Water Treatment ConsiderationsCondenser Considerations Water-Cooled Chiller CondensersAir-Cooled Chiller Condensers Checking Motor Direction Three-Phase CompressorsWater Pumps Condenser FanPart Number Description Water ReservoirEthylene Glycol and Propylene Glycol Curves Finishing Setup Setting Up Passwords Automatic Water Make-Up OptionInitial Start-Up Page Page Panel Buttons, Indicator Lights, and Switches OperationMicroprocessor Controller Main Status Screen Operator Setpoints Screen Status Screens Access Levels Page Controller Setpoints Menu Screen Optional Communications AlarmsGP Series Portable Chillers Operation Filter Cleaning MaintenanceLubrication Maintaining the CondenserPreventative Maintenance Service Maintaining the EvaporatorEvaporator Process Piping Y-Strainer GP Series Portable Chillers Troubleshooting TroubleshootingGP Series Portable Chillers Troubleshooting Appendix Warranty ReturnsReturned Material Policy Credit ReturnsTechnical Assistance Service DepartmentParts Department Sales DepartmentAir-Cooled Portable Chillers SpecificationsPAC-40 PWC-20 Water-Cooled Portable ChillersPWC-50 Hertz Pump Curves Pump Curves, Flow, and Pressure ConsiderationsCalculating Chiller Nominal Flow and Pressure to Process Electrical Schematic
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