Liebert Air Cooled - Manual (Page 40)

System Maintenance
36
Table 9 Troubleshooting
Symptom Possible Cause Check or Remedy
Condenser will not start
No power to condenser Check voltage at input terminal block
Circuit breaker for low voltage
transformer in condenser is tripped
Locate problem in condenser electrical
panel and repair
No low voltage signal to/from indoor unit Locate open circuit and repair
Low indoor unit
suction pressure
Insufficient refrigerant in system Check for leaks, repair, and add refrigerant
Fan-cycling ambient thermostats
setpoints too low
Check schematic for recommended
setpoints and adjust.
Low discharge pressure
Faulty head pressure control valve
or condenser FSC/VFD control
Replace if defective
High discharge pressure
Dirty condenser fins Clean coil
Condenser fans not operating
Check for low voltage signal from indoor unit
Check fan motors and fuses
Check for correct ambient thermostat
setpoints, as applicable.
High refrigerant charge Check refrigerant charge
VFD Condenser trips out
on overvoltage
(OU displayed on VFD
controller)
Supply voltage is Delta configuration
or is ungrounded/high impedance
Shut off AC voltage, locate the VFD, pull out
the EMC tab and reconnect power
TVSS indicator lights are
extinguished or red LED is
illuminated and monitoring
terminals 11/12 are closed
No voltage or improper phasing exists
at condenser
Check voltage at input terminal block
Electrical connections to TVSS are
faulty
Locate connection problem and repair
A surge exceeding the rating
of the TVSS has occurred
Replace TVSS and inspect other
components for damage and replace them if
necessary