Carrier Super Inverter Series Service Manual page 77

18.3.3.5 High pressure protection (ODU P1)(For 38QUS036DS4*, 38QUS042DS5*)
High pressure protection
High pressure protection
Whether the wiring
Whether the wiring
between the high pressure
between the high pressure
switch and main control
switch and main control
board is connected well or
board is connected well or
correctly
correctly
Yes
Whether the high
Whether the high
pressure protector
pressure protector
is broken
is broken
Method:
Disconnect the plug.
Method:
Disconnect the plug.
Measure the resistance of
Measure the resistance of
high pressure protector, if
high pressure protector, if
the protector is normal the
the protector is normal the
value is o,
value is o,
Yes
Check whether the outdoor
Check whether the outdoor
ambient temperature is
ambient temperature is
higher than 50℃
higher than 50℃
No
Check if the outdoor unit
Check if the outdoor unit
ventilation is good
ventilation is good
Yes
Check if the outdoor fan runs
Check if the outdoor fan runs
properly
properly
Yes
Check whether the heat
Check whether the heat
exchanger is dirty
exchanger is dirty
No
Replace outdoor main
Replace outdoor main
board
board
No
Check whether the refrigerant
Check whether the refrigerant
system is ok
system is ok
No
Connect it well
Connect it well
the
the
No
Replace high pressure protector
Replace high pressure protector
Yes Stop the unit
Stop the unit
NO
Make the outdoor unit ventilate well
Make the outdoor unit ventilate well
please refer to the solution of fan
please refer to the solution of fan
speed has been out of control
speed has been out of control
No
malfunction . Find out the cause and
malfunction . Find out the cause and
have it solved.
have it solved.
Yes
Clean the heat exchanger
Clean the heat exchanger
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