Infrared Humidifier Troubleshooting; Heating System Troubleshooting - Emerson Liebert.PEX+ Series User Manual

72 Chapter 8 Troubleshooting
Symptom
Dual cooling /free cool
unit, FC (free cooling)
fan cannot start when
there is chilled water
provided
Note:
The refrigerant requirement is the precondition for judging the potential causes listed in this Table

8.3 Infrared Humidifier Troubleshooting

The troubleshooting of infrared humidifier is listed in Table8-3.
Symptom
Humidiifcation
ineffective

8.4 Heating System Troubleshooting

The troubleshooting of heat system is listed in Table8-4.
Symptom
Heating system cannot start, the
contactor cannot close
Potential causes
The difference between room air return
temperature and setting temperature is
too high (more than A138 setting
value),and the alarm record can display
the FC fan off time for one hour
Under the chilled water inlet normal
temperature, FC will not start, and FC
stop for one hour is impossible, it means
the difference between unit air return
temperature and water inlet temperature
is lower
Table 8-3 Troubleshooting of infrared humidifier
Potential causes
Check the water supply
Check that the water supply solenoid valve is working
No water in water pan
Check the state of the high water-level switch and water level regulator
Check that the water supply pipe is not clogged
Check the contactor, and check the circuit voltage of the contactor
The humidification
Check the opened safety devices of the infrared humidifier: water pan
contactor does not over-temperature protection switch and lamp over-temperature protection switch.
close Use a jumper to shot terminals P35-6 and P35-5. If the contactor closes, replace
the series-connected safety device, and remove the jumper
Check that the air flow lose switch connection is normal. Examine whether there
Air flow lose switch
is24Vac voltage between P36-7 and E1 after startup, if there is not, you should
failure
check whether the air flow lose switch is damaged
Humidifier main power Check that the humidifier MCB is closed;
failure In humidifier contactor closed state, check that L1, L2 and L3 voltages are normal
Infrared humidifier lamp
Replace the lamp
burned
Table 8-4 Troubleshooting of heating system
Potential causes
No heating demand
Liebert. PEX+Series Precision Air Conditioner
Items to be examined or handled
Set the preset temperature after the first startup, the unit
will power off, restart the system can run the FC system;
when the unit is in normal state, but the FC fan stops for
one hour, it means that the present refrigeration
requirement is higher, at this point, you should start the
compressor refrigeration
1) Examine the chilled water inlet temperature, and
compare it with the free cool temperature (the free cool
temperature can be gained from the temperature sensor
installed on the chilled water inlet pipe, ans be read from
User Menu/SENSOR DATA). If the difference is larger,
check whether the sensor installation as well as the
sensor is damaged;
2) To start FC, you should ensure the difference between
the unit air return temperature and water inlet
temperature exceed S138. Maybe the reason is that the
water inlet temperature is too high or the unit preset
temperature is too low, you can properly reduce S138
preset value to start FC. Note that too low S138 preset
value may result in the larger temperature change in
equipment room
Items to be examined or handled
Items to be examined or handled
Check the state of the iCOM controller, and verify
whether there is a humidifying demand
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