Freeze-Up Protection Control, Heating Peak-Cut Control - Daikin 4MXS-R Series Service Manual

Troubleshooting for RA Indoor Unit
5.2

Freeze-up Protection Control, Heating Peak-cut Control

A5
Error Code
Method of Error
Detection
Error Decision
Conditions
Supposed
Causes
Troubleshooting
Check No.01
Refer to P.209
Check the dust accumulation on
the indoor heat exchanger.
153
Freeze-up protection control
During cooling operation, the freeze-up protection control (operation halt) is activated according
to the temperature detected by the indoor heat exchanger thermistor.
Heating peak-cut control
During heating operation, the temperature detected by the indoor heat exchanger thermistor is
used for the heating peak-cut control (operation halt, outdoor fan stop, etc.)
Freeze-up protection control
During cooling operation, the indoor heat exchanger temperature is below 0°C (32°F).
Heating peak-cut control
During heating operation, the indoor heat exchanger temperature is above 65°C (149°F).
Short-circuited air
Clogged air filter of the indoor unit
Dust accumulation on the indoor heat exchanger
Defective indoor heat exchanger thermistor
Defective indoor unit PCB
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Check the air passage.
Is there any short circuit?
NO
Check the air filter.
Dirty?
NO
Dirty?
NO
Check No. 01
Check the indoor heat exchanger
thermistor.
As
described in the
thermistor characteristic
chart?
YES
YES
YES
YES
NO
SiUS121736EA
Provide sufficient air passage.
Clean the air filter.
Clean the indoor heat
exchanger.
Replace the indoor heat
exchanger thermistor.
Replace the indoor unit PCB
(control PCB).
(R21064)
Service Diagnosis