270
25.2.23 Indoor Freeze-up Protection (H99)
Error Code will not display (no Timer LED blinking) but store in EEPROM
Malfunction Decision Conditions
Freeze prevention control takes place (when indoor pipe temperature is lower than 2°C)
Malfunction Caused
Air short circuit at indoor unit
Clogged indoor unit air filter
Dust accumulation on the indoor unit heat exchanger
2/3 way valve closed
Faulty indoor unit fan motor
Refrigerant shortage (refrigerant leakage)
Clogged expansion valve or strainer
Faulty indoor pipe temperature sensor
Faulty indoor unit PCB
Troubleshooting
When abnormality indication starts again
Is the air filter dirty?
● Clean the air filter
● Clean the indoor unit heat exchanger
Check the indoor unit air filter
Is the indoor unit heat exchanger dirty?
Is there any short circuit?
Check the air passage
● Provide sufficient air passage
Does it conform to the sensor characteristic chart?
Check the gas leakage. Is Oil oozing out from the
2/3 way valve?
● Replace the indoor unit PCB
● Replace the indoor pipe temperarure
sensor
● Repair the pipe flare or union nuts
● Reclaim and recharge refrigerant
● Replace the indoor unit fan motor and/or
indoor unit PCB.
Check the dust accumulation on the indoor unit heat
exchanger
YES
For safety reason and to prevent
component breakdown, always switch
off the power before remove and
connect the component.
YES
YES
YES
NO
● Open the 2/3 way valve.
Check if 2/3 way valve is closed?
YES
YES
Check if expansion valve or strainer clogged
(ice formed)?
YES
NO
NO
Check if indoor fan motor operated normally?
Check the indoor pipe temperature sensor
NO
● Reclaim and recharge with correct
amount of refrigerant.
NO
NO
YES
Caution
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