42 Chapter 4 System Power-On Commissioning
2) For the EC fan model, the fan itself does not require phase sequence; therefore, the phase sequence needs to be
checked through compressor. After step five static charging refrigerant of
4.2.2 Commissioning Procedures
is
completed, you should first close the connection pipe in the pressure gauge with the refrigerant filling tank, and then
use the straight screwdriver to press, so as to make one compressor contactor in the electric control box contact in
short time and start the compressor. Determine the system phase sequence through observing the high/low value in
pressure gauge that connected to the system, if the system is unable to quickly build high and low pressure, it means
the phase sequence is wrong, you should exchange any two phases of the L line of the power supply.
4.2.2 Commissioning Procedures
1. Switch off the MCBs of all components. Switch on the main isolation switch and control board MCBs. Check that the
control voltage is 24Vac±10%.
2. Switch on the fan MCB. Press the fan contactor to start the fan and make sure the fan blowing direction is correct.
Start the unit and measure all the operation phase currents of the fan.
3. Switch on the electric heater MCB and change the temperature setpoint to start the electric heater, or start it
manually. Measure all the operation phase currents of the electric heater.
To trigger the electric heater, you should:
Enter the ‘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 electric
heater contactor will be closed and the LCD will display 100% output of the electric heater. Adjust the temperature
setting value to ‘T
setting temp
’ (T
setting temp
= T
return air temp
- 5). Wait for 1min, and then the electric heater will stop working. It
indicates that the heating function is normal. Keep this temperature value and no heating requirement is needed. Then
continue with the following procedures.
Note
Do not manually press the infrared humidifier contactor unless there is water in the humidifier pan.
4. Switch on the infrared humidifier MCB and change the humidity setpoint to start the infrared humidifier, or start it
manually. Measure all the operation phase currents of the infrared humidifier. In addition, inject water manually to
check that the charging pipe and drain pipe do not leak, and that the drain pipe is clear.
To trigger the infrared humidifier, you should:
Enter the ‘USER MENUS’ -> ‘SETPOINTS’ -> ‘HUM SET’ to adjust the humidity setting value to ‘T
setting hum
’ (T
setting hum
=
T
ambient hum
+ 10%, ‘T
ambient hum
’ is the present ambient humidity on the LCD). Wait for 1min, and the humidifier contactor
will be closed and the LCD will display 100% humidifying output. Adjust the temperature setting value to ‘T
setting hum
’
(T
setting hum
= T
ambient hum
- 10%). Wait for 1min, and then the humidifier will stop working. It indicates that the humidifying
function is normal. Keep this humidity value and no humidifier requirement is needed. Then continue with the following
procedures.
Note
After commissioning, restore the temperature and humidity setpoints to the default values or original setpoints.
5. Connect the compound pressure gauge to the corresponding high and low pressure schrader valves. Evacuate the
cooling system vacuum to -30in.Hg (pumping time: >3hr), and hold the state for 4hr. The pressure should not rise, and
the color of the sight glass is normal (to ensure the cooling system vacuum and dry effect, evacuate the cooling
system repeatedly at least three times).
After checking the vacuum state of the cooling system, charge with liquid refrigerant (usually charge until the
pressures inside the refrigerant container equalizes with that in the cooling system).
Connect the pressure gauge to the refrigerant cylinder.
Switch on the compressor MCB and condenser MCB.
1) Change the temperature setpoint to start cooling, or start cooling manually. Make sure that the dehumidification and
HGBP are in closed states. Measure all the operation phase currents of the compressor in real time.
To start cooling (start the compressor), you should:
Make sure that the unit chilled water is in closed state, and enter ‘SERVICE MENU’ -> ‘SETPOINTS’ to set S138 to
‘20K’.
Liebert.PEX2 Series Air Conditioner User Manual
Summary of Contents for Liebert PEX Series
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