Trane PRGD series, Installation, Operation And Maintenance Manual

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PRGD-SVX01F-EN 7
Purge System Overview
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IIm mp po orrtta an ntt:: The PRGD purge uses R-404A refrigerant
and is used with chillers using R-123 and
OIL00022. Verify proper refrigerant and oil
for the PRGD purge and chiller before
proceeding!
This guide describes the operation and maintenance of
a Trane® EarthWise™ purge system with Tracer®
AdaptiView™ controls. Tracer® AdaptiView™ controls
include the Tracer® UC800 controller and the Tracer®
AdaptiView™ display.
General Information
Centrifugal chillers that use low-pressure refrigerants,
such as R-123, operate with areas of the chiller at less
than atmospheric pressure. Non-condensables in the
air, such as water and nitrogen vapor, may leak into
these low-pressure areas and accumulate in the
condenser. If these non-condensables are not
removed, the condenser loses its ability to condense
refrigerant efficiently and the pressure of the
condenser increases. Increased condenser pressure
lowers the chiller’s efficiency and capacity.
A purge system is required on low-pressure centrifugal
chillers. It is a device that is externally mounted on the
chiller. Its purpose is to remove non-condensable
materials that have leaked into the machine.
N No otte e:: For convenience, the term “air” is often used in
describing non-condensables removed by the
purge system, although any other non-
condensable materials that may exist in the
chiller are also removed by the purge system.
Reference Sources
The following reference documents may be helpful
resources for EarthWise™ purge system operation and
maintenance:
• Installation, Operation, and Maintenance Guide:
CDHF and CDHG Water-cooled CenTraVac Chillers
with Tracer AdaptiView Control
(CDHF-SVX01*-EN)
• Installation, Operation, and Maintenance Guide:
CVHE, CVHF, CVHG Water-cooled CenTraVac
Chillers with Tracer AdaptiView Control (CVHE-
SVX02*-EN)
• Installation, Operation, and Maintenance Guide:
CVHL Water-cooled CenTraVac Chillers with Tracer
AdaptiView Control
(CVHL-SVX01*-EN)
• Installation, Operation, and Maintenance Guide:
Series S CVHS Water-cooled CenTraVac Chillers
with Tracer AdaptiView Control and AdaptiSpeed
Technology
(CVHS-SVX01*-EN)
• Diagnostics Manual: Diagnostic Descriptions,
Troubleshooting Tables, and Control Component
Overview for Water-cooled CenTraVac Chillers with
Tracer AdaptiView Control
(CTV-SVD03*-EN)
• Programming Guide: Tracer TU Service Tool for
Water-cooled CenTraVac Chillers with Tracer
AdaptiView Control
(CTV-SVP02*-EN)
• Operations Guide: Tracer AdaptiView Display for
Water-cooled CenTraVac Chillers
(CTV-SVU01*-EN)
• Getting Started Guide: Tracer TU Service Tool
(TTU-SVN01*-EN)
How a Purge System Works
From a functional standpoint, the purge system can be
divided into subsystems of components. This section
identifies and describes the function of these
subsystems.
The following list identifies these subsystems and their
components; the following figures illustrate them:
• Refrigeration circuit subsystem
– Purge tank
– Purge evaporator coil (inside purge tank)
– 1/4 hp air-cooled condensing unit (compressor,
fan, condensing coil)
– Automatic expansion valve
– Chiller refrigerant supply line
– Chiller refrigerant return line (includes filter-
drier and moisture-indicating sight glass)
• Purge tank subsystem
– Purge tank
– Purge evaporator coil (inside purge tank)
– Pressure-relief device (fusible plug)
– Liquid level sensor (float switch)
–
Supply and return lines to the chiller condenser
• Pump-out subsystem
– Pump-out compressor
– Pump-out solenoid valve
• Carbon tank and regeneration subsystem
– Carbon tank
– Carbon tank heater
– Regeneration solenoid valve