Hitachi mini-HNRQ1 Series Service Manual page 82

Alarm
02
Code
● The alarm code is flashed on the 7-segment display of the outdoor unit.
● The alarm code is displayed on the wired controller of the indoor unit.
Event
Activation of
High Pressure
Switch due to
Excessively
Increasing
High Pressure
Activation of Protection Device (High Pressure Switch) in Outdoor Unit
Cause
Excessively High Temp.
Air to Indoor Unit
Heat Exchanger
Failure of
Pressure
Switch
Failure of
High Contact
Pressure Failure
Switch
Incorrect
Connection
Overcharged Refrigerant
Contamination of
Non-condensable Gas into
Refrigerant System
Clogging of Discharge Pipe
Liquid line stop valve or
gas line stop valve is
not fully opened.
Insufficient Airflow to
Heat Exchanger
Cooling: O.U. Heat Exchanger
Heating: I.U. Heat Exchanger
Check Item
Calculate heat load.
Check for hot air near
ceiling (Heating).
Check for short
circuited air (Heating).
Check for other
heat source.
Measure discharge
pressure.
Check continuity after
decreasing of pressure.
Measure resistance
with tester.
Check connection.
Check system operating
temp.
Check ambient temp.
and pressure.
Check for clogging.
Check stop valves.
Check for clogging of
heat exchanger.
Check for dust on
air filter.
Check for any obstacles
at inlet or outlet of
heat exchanger.
Check service space
is sufficient.
Check fan motor speed.
Cooling: Outdoor Fan
Heating: Indoor Fan
75
TROUBLESHOOTING
Action
(Turn OFF Main Switch)
Reduce heat load or
use a larger unit.
Make circulation better.
Remove
short-circuited air.
Remove heat source.
Replace it if faulty.
Repair looseness.
Replace connector.
Repair connection.
Charge correct
amount of refrigerant.
Recharge refrigerant
after vacuum pumping.
Remove clogging.
Fully open stop valves.
Remove clogging.
Remove dust.
Remove obstacles.
Secure sufficient
service space.
Replace fan motor
if faulty.