Справочник Пользователя для Liebert 3000

If these two alarms are displayed at the same time, the temperature input signal is lost (or the 

humidity is out of sensor range: 15 to 85% RH). Dashes will be displayed for the temperature reading. 

The control system will initiate 100% cooling. Check for a disconnected cable or a failed sensor.

This alarm is activated by the high water float switch in the humidifier pan assembly. The high water 

float switch is normally closed and opens upon alarm condition. Check for drain clog and, if present, 

clean drain. Check for float switch stuck high; replace the switch as necessary. Check for proper oper-

ation of the humidifier water makeup valve.

This alarm is activated by a signal from the humidifier control indicating that the canister needs to be 

replaced.

A differential air pressure switch is used to indicate loss of air flow in Challenger 3000 units.
Check for blockage of unit air outlet or inlet. Check blower motor fuses and overload reset. Check for 

broken belts. Make sure blower wheels are tight to shaft. Run diagnostics to see if the fan contactor is 

working properly.

If the unit has lost power, or the disconnect switch was turned off before the unit ON switch was 

pressed (to turn the unit Off), this local alarm will occur when power is restored to the unit. A Liebert 

remote monitoring unit (optional) will immediately indicate loss of power.

If the return air humidity has decreased to the Low Humidity Alarm setpoint, check to make sure 

that the unit is setup for humidification (check DIP switch). Check for proper setpoints. Does the 

room have a vapor barrier to seal it from outdoor humidity? Are doors or windows open to outside air? 

Run diagnostics to make sure the humidifier system is working properly.

A pressure switch monitors the suction pressure at the compressor inlet to monitor whether pressure 

has dropped below a factory preset point while the compressor is in cooling operation. When pressure 

drops below a factory preset point, the switch opens. After the positive start kit time delay, and the 

switch stays open for five minutes, the alarm is activated. The alarm stays active for 90 minutes.
Look for conditions that would cause loss of refrigerant. Check for piping problems such as leaks or 

crimped lines. Check for inoperative components such as liquid line solenoid valve, low pressure 

switch, expansion valve, and head pressure control valve. Check for closed service valves in the liquid 

line or at the condenser or receiver.

If the return air temperature has decreased to the Low Temperature Alarm setpoint, check for proper 

setpoints. Run diagnostics to make sure all heating components are operating (contactors and 

reheats). Are reheats drawing the proper current? (See nameplate for amp rating.)

An optional tri-block overload is required for this alarm, and may or may not replace internal motor 

overload, depending on your model. The overload device is located next to the main fan contactor in 

the line voltage section. The alarm is activated when the overload is tripped.