TROUBLESHOOTING
–
REPAIRS
CHILLER-IOM-2004-E
51
2.
CONTROL DEVICES
Operation
By reacting to compressor discharge pressure, the high pressure switch monitors efficiency of the condenser. Poor efficiency, the result of
an excessive condensing pressure, is usually caused by:
•
A dirty condenser
•
Low water flow
•
Low air flow
The low pressure switch monitors the pressure at which the refrigerant evaporates in the evaporator tubes. Low evaporating pressure is
usually caused by:
•
Low refrigerant charge
•
A faulty expansion valve
•
An obstructed liquid line filter-drier
•
A damaged compressor cylinder bank unloaded.
The control thermostat monitors chilled water temperature at the evaporator inlet. The most common causes of abnormal temperatures in this
zone are:
•
Low water flow
•
Thermostat setting too low
The above information does not represent a complete analysis of the refrigeration system. It is intended to familiarize the
operator with unit operation and to provide him with the technical data required to enable him to recognize, correct or report
a fault.
Only trained and qualified personnel is authorized to service and maintain this equipment
