86 Chapter 7 System Operation And Maintenance
7.2 Filter
To ensure efficient operation, the filter must be checked once a month, and be replaced as required.
Switch off the power before replacing the filter. You do not need to adjust the setpoint of the filter clog switch if the new
filter is of the same model. Otherwise, you need to adjust the setpoint. The filter clog switch is located in the electric
control box. It compares the air pressures before and after the filter through a black hose.
To adjust the setpoint of the filter clog switch, you should:
1. After replacing the filter, restore and seal all the panels, so that the alarm point can be found precisely.
2. With the fan running, rotate the rotary switch of the filter clogging switch counter clockwise to trigger the filter alarm.
3. Rotate the rotary switch clockwise for 1 rotation, or rotate it to the required filter replacing point.
Note
1. Set the setpoint properly. Otherwise, the filter alarm may be triggered too frequently; or, in the opposite case, the dust
accumulation on the filter could not trigger the alarm, resulting in low system airflow and endangering the system operation.
2. If you are unsure about the setpoint, consult Emerson before using a filter of a different model to replace the old one.
7.3 Fan Components
7.3.1 FC Fan
The fan components that require regular checking include belt, motor bracket, fan bearing and blades.
The fan and the installation board are designed in consistency. The belt tension is regulated automatically under the
force of gravity to reduce the fan vibration and protect the belt.
Fan bearing and blades
Check the fan regularly to make sure the bearing is secure. Rotate the blades and make sure that they do not contact
the housing. Because the bearing is permanently sealed and self-lubricated, check for signs of wearing when
adjusting the belt. Roll the belt and observe the motion of the fan bearing. If any abnormal displacement is observed,
replace the bearing.
Belt
Measure the belt tension with a tension meter. You can also press down the belt at the middle point between the two
pulleys. The displacement should be 12mm ~ 25mm (1/2” ~ 1”).
If the belt is found worn or distorted, replace it with a new belt. The new belt should be of the same model as the old
one.
Motor
To replace the failed motor, you need to be very careful, especially with the upflow unit. Use a dedicated fixture to hold
the motor before removing the fixing bolts at the bottom of the motor.
7.3.2 EC Fan
The EC fan needs main power supply with 380Vac input, meanwhile, it exercises the speed regulation according to the
0 ~ 10Vdc analog signals output from the control board. If the EC fan is in abnormal state, please check the analog
signals and main power supply carefully.
Besides, the main fan overload alarm of the control board is series connected with the alarms of the EC fan. When the
EC fan is over hot, loss of main power supply and clogging, the unit will generate EC fan fault alarm.
7.4 Infrared Humidifier
During the normal operation of the infrared humidifier, sediment will accumulate on its water pan. To ensure efficient
operation of the infrared humidifier, you need to clean the sediment regularly. However, the cleansing cycle varies
because the water is different in different regions. It is recommended to check, and cleanse (when necessary) the
water pan, once a month.
Liebert.PEX2 Series Air Conditioner User Manual
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