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16.5.26 Indoor Freeze-up Protection (H99)
Malfunction Decision Conditions:
During anti-freezing control in cooling operation, when the indoor refrigerant liquid temperature < 0°C.
Malfunction Caused:
1 Faulty
water
pump.
2 Insufficient water flow rate in system.
3 Water leak in system.
4 2 way valve partially closed.
5 Clogged expansion valve or strainer.
6 Refrigerant shortage (refrigerant leakage).
7 Faulty indoor refrigerant liquid temperature sensor.
8 Faulty indoor unit PCB (main).
Check the system water pump.
Is the water pump working?
Check the system water passage.
Readjust the water pump
speed.
No
Is the water pump speed
adjusted according to system
hydraulic external static pressure?
Replace the faulty water
pump.
No
Yes
Check the system water
flow rate.
Is there any water leakage?
Fix the system water
leakage.
Yes
Yes
Check refrigerant amount.
Is the additional refrigerant
amount filled correctly?
Reclaim and recharge with
correct amount of refrigerant.
No
Yes
Check for clogged
expansion valve or strainer.
Is the expansion valve or
strainer clogged (ice formed)?
- Replace the expansion
valve and/or strainer
- Reclaim and recharge
refrigerant
Yes
No
Is the 2 way valve partially
closed?
Open the 2 way valve.
Check the 2 way valve.
Check the indoor refrigerant
liquid temperature sensor.
Replace the indoor unit PCB
(main).
Does it conform to the
sensor characteristic chart?
Replace the indoor refrigerant
liquid temperature sensor.
Yes
No
No
No
Yes
Troubleshooting:
For safety reason and to prevent component breakdown,
always switch off the power before remove and connect the component.
Caution