Vertiv Liebert MC - Troubleshooting

22
Liebert
®
MC - UM - 10019237MAN_ENG - 31.03.2022
15.
11. Troubleshooting
Symptom Possible Cause Check or Remedy
Condenser will not start
No power to condenser. Check voltage at input terminal block.
Circuit breaker or fuse 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.
Missing Modbus communication (only for
Controlled Indoor Unit).
Check the cable connection.
Check if the fans have the correct
addressing.
Low discharge pressure
Faulty head pressure control valve or
premium e󰀩ciency control board.
Replace if defective.
High discharge pressure
Dirty condenser ns. Check for low-voltage signal from indoor
unit.
Condenser fans not operating. Check fan motors and fuses.
High refrigerant charge Check refrigerant charge.
Fan will not run
Jumper not installed between 24V and
DIN1 (for Ziehl-Abegg fan motor).
Install jumper between 24V and DIN1
(for Ziehl Abegg fan motor).