Hitachi RAS-(4-12)HRNM(2)(E) - Activation to Protect System from Excessively Low Suction Pressure (Protection from Vacuum Operation) for es Series

8 Troubleshooting
263
SMGB0064 rev.0 - 08/2011
8
Alarm code
47
Activation to Protect System from Excessively Low Suction Pressure (Protection from Vacuum Opera-
tion) for ES Series
• The RUN LED ickers and “ALARM” is displayed on the remote control switch.
• The unit number, the alarm code and the unit code are alternately displayed on the set temperature section. The unit
number and the alarm code are displayed on the display of the outdoor unit PCB.
- In the case that the evaporating temperature (Cooling: Liquid Refrigerant Piping Temp. of Indoor Unit, Heating:
Evaporating Temp. of Outdoor Unit) is lower than -37 °C (250~350 kΩ) and the thermistor on top of compressor
is higher than 90 °C. for 10 minutes, retry operation is performed 3 minutes after compressor stoppage.However,
when the state occurs more than 3 times including 3 in one hour, this alarm code is indicated.
Phenomenon Cause Check item
Action
(Turn OFF Main Switch).
– Faulty indoor unit liquid
refrigerant temp. thermistor
– Faulty outdoor unit
evaporating temp. thermistor
Fault Check resistance. Replace thermistor if faulty.
Incorrect Connection Check wiring to PCB. Repair wiring and connections.
Faulty PCB
(Outdoor Unit, Indoor Unit)
Replace PCB and check operation. Replace PCB if faulty.
Excessively Low Suction Pressure
(in Vacuum)
Liquid Line Stop Valve is not open
before Operation
Check stop valve. Fully open stop valve.
Faulty or Malfunction of Expansion
Valve
Check for clogging. Remove clogging.
Check connecting wiring and
connectors.
Replace connector.
Check operating sound from coil. Replace coil.
Check discharge gas thermistor. Replace thermistor.
Check attaching state of discharge
gas thermistor.
Reattach thermistor.
Refrigerant Leakage
Check each temp.
and pressure.
Charge refrigerant after vacuum
pumping.
Check gas leakage part.
Correctly charge refrigerant after
repairing gas leakage.
Faulty Outdoor Fan at heating
Operation
Faulty Outdoor Fan Motor
Measure coil resistance and
insulating resistance.
Replace outdoor fan motor if faulty.