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4.2
Routine maintenance
4.2.1
Check condenser performance
It is important to periodically check the internal cleanliness of the copper tubes, in order to prevent deteriorated
performance. This check can be carried out by checking that the difference between the condensation temperature and
the condenser outlet water temperature on the microprocessor does not exceed 4° C. If deviations from this value occur,
run the specific cleaning procedure.
4.2.2
Electronic expansion valve
EWWD(H)_DZ units use an a main electronic expansion valve for both single and dual compressor machines. The valves
are managed and controlled by the main electronic controller that optimizes the flow of refrigerant gas to the evaporator
according to machine operating conditions. The valve control logic prevents, together with compressor load control,
machine operations beyond the allowed operation limits. Normally, the only maintenance required for this device is
checking valve management via controller.
4.2.3
Cooling circuit
Cooling circuit maintenance consists of recording operating conditions and making sure the unit has the correct amount of
refrigerant. Record the following for each circuit upon inspection:
Discharge and suction pressure
Discharge and suction temperature
Liquid temperature
Evaporator inlet/outlet water temperature
Condenser inlet/outlet water temperature
Absorbed current, power voltage and percent compressor load
Significant discharge subcooling and/or superheating value changes, can be a symptom of low refrigerant load.
The correct unit discharge superheating value of the unit at full load must be between 8 and 15° C with R134a fluid, while
subcooling must be between 3.5 and 6.0° C (machine at full load).
