Sakata SOB-50VA Service Manual page 105

Light Commercial R410A on-off
f. Open-circuit and short-circuit trouble of T4
Is connection to connector of temp. sensor good?
Yes
Check the resistance of the temp. sensor according to Annex 1
Is it the resistance is normal?
Yes
Indoor PCB is defective.
g. High temperature protection of condenser
High temperature protection of condenser
Check the resistance of the temp. sensor
according to Annex 1, is it normal?
Yes
Possible reason
1. Air or other gas in the refrigerant.
2. Heat exchanger is dirty
3. Outdoor fan or fan blade is
defective
4. Outdoor unit is bad ventilation
Refrigerant is leakage
5.
Outdoor PCB is defective
6.
Outdoor Units. Troubleshooting
No
Replace the sensor
No
Replace the sensor
No
Repair connector
S13-01.01.13en
104