Chapter 4 System Power-On Commissioning 43
Enter ‘USER MENUS’ -> ‘SETPOINTS’ -> ‘TEMP SET’ to adjust the temperature setting value to ‘T
setting temp
’ (T
setting temp
= T
return air temp
- 5, ‘T
return air temp
’ is the present ambient temperature on the LCD). Wait for 1min, and the compressor
contactor will be closed and the LCD will display 100% cooling requirement. After at least 3min operation, change the
temperature setting value to ‘T
return air temp
’ (T
setting temp
= T
return air temp
+ 5). Wait for 30s, and then the compressor will stop
working. It indicates that the cooling function is normal.
Note
After commissioning, restore the temperature setpoint to the default or original setpoint.
2) Check the operation current of the condenser fan, and check that the fan runs stably.
3) Start the compressor, and charge refrigerant gas (R22) or refrigerant liquid (R407C) slowly to the compressor inlet
until the subcooling degree reaches 8°C ~ 10°C and the sight glass is clear. The condensing temperature should be
kept at 45°C.
Keep charging and adjust the thermostatic expansion valve to 41°F ~ 46.4°F superheat degree. The adjustment step
of the valve should be smaller than 1/4 round, and the interval between two steps should be at least 15min.
Observe the compressor suction pipes and make sure that there is no water condensing on the surface of the
compressor and the pipes, so as to avoid the risk of liquid slugging the compressor.
At the condition of 22°C/50% return air state and 16bar ~ 17bar condensing pressure, the compressor suction
pressure should be above 5bar.
At the condition of 24°C/50% return air state and 16br ~ 17br condensing pressure, the compressor suction pressure
should be above 5.5bar.
4) Check the dehumidification function
To trigger dehumidification, you should:
Change the humidify setting (see
) to 10% lower than the indoor RH. The control system
should then trigger the call for dehumidification, the dehumidification solenoid valve switches on the dehumidification
indicator Q3 on the control board turns on. Then change the humidity setting higher than the indoor RH. If the
dehumidification solenoid valve of the FC fan unit switches off, and the airflow of the EC fan unit drops while the
dehumidification indicator Q3 turns off, it means the dehumidification function is normal. Note that during the
commissioning process, if the indoor temperature is 3°C higher than the temperature setting, the system may enter the
forced cooling mode, and the dehumidification demand will not be responded.
6. Commission the chilled water function: Make sure that the chilled water source is supplied normally. The
temperature of the chilled water ranges from 7.6°C to 9°C. Set the temperature point to trigger FC demand, and the
chilled water valve is opened.
To trigger the chilled water demand, you should:
Enter ‘SERVICE MENUS’ -> ‘SETPOINTS’ to set S138 to ‘8K’. Enter the ‘SERVICE MENUS’ -> ‘SETPOINTS’ to set
S138 to ‘8K; enter ‘USER MENUS’ -> ‘SETPOINTS’ -> ‘HUM SET’ to adjust the humidity setting value to ‘T
setting hum
’
(T
setting hum
= T
ambient hum
) and then enter ‘TEMP SET’ to adjust the temperature setting value ‘T
setting temp
’ (T
setting temp
=
T
return air temp
-2). Wait for 30s, and the FC requirement will be triggered and the chilled water valve will be open.
Note
After commissioning, restore the temperature setpoint to the default or original setpoint.
4.2.3 Inspection After Commissioning
After commissioning, check and confirm it according to Table 4-1.
Table 4-1 Inspection after commissioning
Items Results
Check that all output functions are automatic
Check that the temperature & humidity setpoints and control
precisions are set correctly
Check that other functions are set correctly
Liebert.PEX2 Series Air Conditioner User Manual
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