Daikin EWWH955DZXEA2 [23/32] Routine maintenance

D-EIMWC01405-18EN- 23/32

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).