Trane CGCN Installation Operation & Maintenance page 47

Standard checks
Operation description
Compressors oil level
Clean coil
Inlet temperature (overheating)
Water circuits filling
Fans and compressors motors electrical input
Power supply and auxiliary power voltage
Refrigerant charge through sight glass
Compressors carter heaters operation
Tightening all electrical connections
Compressors and liquid circuit solenoid valve
Adjusting and safety thermostat calibration
Fans (if present) and compressors contactors state
Evaporator heater operation
Motor and fan (if present) bearing noise
Pressure vessels conditions
Temperature and pressure probes
The unit comes factory-equipped with all the sensors listed below. Periodically check that their measurements are
correct by means of sample instruments (manometers, thermometers); correct readings if necessary using the
microprocessor keyboard. Well-calibrated sensors ensure better efficiency for the unit and a longer lifetime.
Note: refer to the microprocessor use and maintenance manual for a complete description of applications, setting
and adjustments. All sensors are preassembled and connected to the microprocessor.
Outgoing water temperature sensor
This sensor is located on the evaporator outgoing water connection and is used by the microprocessor to control
the unit's load according to the system's thermal load. It also performs the evaporator's antifreeze protection.
Ingoing water temperature sensor
This sensor is located on the evaporator ingoing water connection and is used for monitoring the return water
temperature.
External air temperature sensor
Optional. This sensor allows to monitor the external air temperature on the microprocessor display. It is also used
to carry out the "OAT set point override".
Compressor delivery pressure transducer
This is installed on every compressor and allows to monitor the delivery pressure and to control the ventilators.
Should a increase in condensation pressure arise, the microprocessor will control the compressor load in order to
allow it to function even if choked. It contributes to complementing the oil control logic.
Oil pressure transducer
This is installed on every compressor and allows to monitor the oil pressure. Using this sensor, the
microprocessor informs the operator on the conditions of the oil filter and on how the lubrication system is
functioning. By working together with the high- and low-pressure transducers, it protects the compressor from
problems deriving from poor lubrication.
Low-pressure transducer
This is installed on every compressor and allow to monitor the compressor intake pressure along with low
pressure alarms. It contributes to complementing the oil control logic.
Intake sensor
This is installed optionally (if the electronic expansion valve has been requested) on each compressor, and allows
to monitor the intake temperature. The microprocessor manages the electronic expansion valve control by means
of this sensor.
Compressor discharge temperature sensor
This is installed on each compressor and allows to monitor compressor discharge temperature and oil
temperature. The microprocessor controls liquid injection by means of this sensor and shuts down the
compressor in case of alarm in the event that the discharge temperature reaches 110°C. It also protects the
compressor from possible startups with liquid.
Recommended frequency
Monthly
Monthly
Monthly
Monthly
Monthly
Monthly
Monthly
Monthly
Monthly
Semiannual
Quarterly
Quarterly
Quarterly
Semiannual
Yearly