Carrier 38MBRCQ36AA3 - High Pressure Protection; PC 30 Diagnosis and Solution

38MBRC: Service Manual
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
32
PC 30 (High Pressure Protection Diagnosis and Solution)
Description: Outdoor pressure switch cuts off the system when high pressure is higher than 4.4 MPa
Recommended parts to prepare:
• Connection wires
•Pressure switch
• Outdoor fan
• Outdoor main PCB
Troubleshooting and repair:
Are the high pressure switch
and main control board wired
correctly?
,
,
Method: Disconnect the plug.
Measure the resistance of the
high pressure protector , if the
protector is normal the value is
o, Does a problem still exist ?
Yes
Yes
No
No
Is the high pressure
protector broken?
ć
Is the outdoor ambient
temperature is higher than
50ć?
No
Yes
Check if the outdoor unit
ventilation is good
Yes
Is the heat exchanger dirty ?
No
Yes
Replace outdoor main board . Is
the problem resolved?
No
High pressure protection
Is the outdoor fan running
properly?
No
Yes
NO
Connect high pressure switch and
main control board
Replace high pressure protector
Stop the unit
Ensure that the outdoor unit
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t
he
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n
S
p
eed
is
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ge
ā
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.
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Speed is ŽƉĞƌĂƟŶŐŽƵƚƐŝĚĞŽĨŶŽƌŵĂů
rangeāŵĂůĨƵŶĐƟŽŶ.
Clean the heat exchanger
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