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3.0
C
OMPONENT
3.1
System Testing
3.1.1
Environmental Control Functions
The performance of all control circuits can be tested by actuating each of the main functions. This is
done by temporarily changing the setpoints.
Cooling
To test the cooling function, set the setpoint for a temperature of 10°F (5°C) below room temperature.
A call for cooling should be seen and the equipment should begin to cool. A high temperature alarm
may come On. Disregard it. Return setpoint to the desired temperature.
Heating
Reheat may be tested by setting the setpoint for 10°F (5°C) above room temperature. A call for
heating should be seen and the heating coils should begin to heat. Disregard the temperature alarm
and return the setpoint to the desired temperature.
Humidification
To check humidification, set the humidity setpoint for an RH 10% above the room humidity reading.
For infrared humidifiers, the infrared element should come On. Steam generating humidifiers should
click immediately as it energizes. After a short delay, the canister will fill with water. The water will
heat and steam will be produced. Return the humidity setpoint to the desired humidity.
Dehumidification
Dehumidification can be checked by setting the humidity setpoint for an RH 10% below room relative
humidity. The compressor should come On. Return humidity setpoint to the desired humidity.
Electric Panel
The electric panel should be inspected for any loose electrical connections.
WARNING
!
Arc flash and electric shock hazard. Open all local and remote electric power supply
disconnect switches, verify with a voltmeter that power is Off and wear personal protective
clothing over NFPA 70E before working within the electric control enclosure. Failure to
comply can cause injury or death.
The Liebert iCOM does not isolate power from the unit, even in the "Unit Off" mode. Some
internal components require and receive power even during the "Unit Off" mode of the Liebert
iCOM.
The only way to ensure that there is NO voltage inside the unit is to install and open a remote
disconnect switch. Refer to the unit's electrical schematic.
Verify that all power has been disconnected from the unit before attempting to tighten any
fittings or connections.
Control Transformer and Fuses
The control system is divided into four separate circuits. The control voltage circuits are individually
protected by fuses located on the transformer/fuse board. If any of the fuses are blown, first eliminate
shorts, then use spare fuses supplied with unit. Use only type and size of fuse specified for your unit.
The small isolation transformer on the board supplies 24 volts to the main control board. The
transformer is internally protected. If the internal protector opens, the transformer/fuse board must
be replaced. Also check the control voltage fuse on the main control board before replacing the
transformer/fuse board.
Fan Safety Switch
The fan safety switch is in the electric compartment and consists of a diaphragm switch and
interconnecting tubing to the blower scroll. The fan safety switch is wired directly to the control
circuit to activate the alarm system if the airflow is interrupted
O
M
PERATION AND
AINTENANCE
7
Component Operation and Maintenance
Liebert
®
Challenger 3000
™
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Table of Contents
Troubleshooting
