Carrier 38MGRBQ18B-3 - DIAGNOSIS AND SOLUTION (CONT); High Temperature Protection of Condenser

38MGRBQ: Service Manual
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DIAGNOSIS AND SOLUTION (CONT)
P5/PC 0A (High temperature protection of condenser) diagnosis and solution
Troubleshooting
ERROR CODE
P5/PC 0A
MALFUNCTION DECISION
CONDITIONS
When the outdoor pipe temperature is higher than 149°F(65°C), the unit stops and starts again when the
outdoor pipe temperature is less than 125.6°F(52°C)
SUPPOSED CAUSES
Faulty condenser temperature sensor
Heat exchanger is dirty
System block
High temperature protection of
condenser
Yes
.
Is the condenser
temperature sensor
resistance normal?
Refer to Appendix 1.
Replace the temperature sensor
No
No
No
Stop the unit Yes
Check if the outdoor unit
ventilation is good
Yes
Ensure the outdoor unit ventilation
is good
Check whether the heat
exchanger is dirty
No
Clean the heat exchangerYes
Check whether the refrigerant
system is ok
Replace outdoor main board
No
Refrigerant is low; add more.
No
Check if the outdoor fan runs
p
ro
p
er
ly
Check if the outdoor fan runs
properly
.
.
Refer to the Fan Speed is Out of Control
malfunction solution.
Determine the cause and resolve.
No
Yes
No
Correct the connectionNo
Yes
Check
t
he
co
nn
ec
ti
o
n
between tem
p
erature
se
n
so
r
a
n
d
PCB
.
Check the connection
between temperature
sensor and PCB.
Yes
Is the condenser temperature
higher than 149
°F (65°C)?
Is the outdoor ambient
temperature higher
than 122
°F (50°C)?