Pc30 System High Pressure Protection - Carrier 38MBRC Series Service Manual

38MBRC: Service Manual
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:
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
High pressure protection
Are the high pressure switch
and main control board wired
correctly?
Yes
Is the high pressure
protector broken ?
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
Is the outdoor ambient
temperature is higher than
50 ?
No
Check if the outdoor unit
ventilation is good
Yes
Is the outdoor fan running
properly?
Yes
Is the heat exchanger dirty ?
No
Replace outdoor main board . Is
the problem resolved?
No
Connect high pressure switch and
No
main control board
No Replace high pressure protector
Yes
Stop the unit
Ensure that the outdoor unit
NO
No Speed is
Speed is
range
range
Yes
Clean the heat exchanger
32
the Fan
the Fan
.
.