Diagnosis For Overboard And Discharge Malfunction - Carrier 38GRQB12-3 Service Manual

7. Diagnosis for overboard and discharge malfunction (AP1 below is control board of outdoor unit)
Main detection points:
S Is the electron expansion valve well connected? Is the expansion valve damaged?
S Is there a refrigerant leak?
S Is the overload protection damaged?
Malfunction diagnosis process:
No
Replace
overload
protector SAT
After the unit
de-energized
for 20min
Is the overload protector SAT
well connected?
Yes
Under ambient temperature, test the
resistance of overload protector
resistance value 1000
Yes
If the wiring terminal FA
is well connected?
Yes
The resistance value of
firs t 4 l e ad fo ot an d th e
fif th lead fo ot is similar,
less than 100
Replace EKV
coil of electronic
expansion valve
Remove
malfunction?
No
Check refrigerant, if there is
leakage, please refer to unit
specification
Remove
malfunction?
No
Replace
control board
AP1
End
Fig. 43 – Troubleshooting
40
No
Connect wire
No wiring diagram
Yes