Carrier 38QUS014DS2 series, Service Manual

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18.3.3.7 Current protection of compressor (ODU P3)
Current protection of compressor
Judge 1: Check whether the
input current of the power
supply wire is higher than max
protection current value
Yes
Replace the electric control box
Check whether
the refrigerant
system is ok
Judge 2: Check whether the
outdoor ambient
temperature is higher than
50
℃
No
Stop the unit Yes
Judge 3: Check whether the
outdoor unit is bad ventilation
No
Make the outdoor unit ventilate well Yes
Judge 5: The refrigerant
pipe is blocked
No
Let the refrigerant out, then use the high
pressure nitrogen or refrigerant to blow pipe,
vacuumize and charge the refrigerant again
Yes
Judge 4: Check whether the
heat exchanger is dirty
No
Clean the heat exchanger Yes
Yes
Replace outdoor main
board,and check whether
the system can run normally
No
Yes
Trouble is solved