Sakata SOB-50VA Service Manual page 104

Light Commercial R410A on-off
d. Protection of pressure or temp.
Protection of pressure or temp.
Yes
Is it k1 or K2 open ?
Is temp. protective switch K1 open
Yes
Possible reason
1. The wires is loose to K1
2. Air or other gas in the refrigerant.
3. Heat exchanger is dirty
Outdoor fan or fan blade is
4.
defective
Outdoor unit is bad ventilation
5.
Refrigerant is leakage
6.
K1 switch is defective
7.
e. Open-circuit and short-circuit trouble of T3
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.
Outdoor Units. Troubleshooting
Is pressure protective switch K2 open
Yes
Possible reason
1. The wires is loose to K2
2. Air or other gas in the refrigerant.
3. Heat exchanger is dirty
Outdoor fan or fan blade is
4.
defective
Outdoor unit is bad ventilation
5.
Refrigerant is two much
6.
K2 switch is defective
7.
No
Replace the sensor
No
Repair connector
S13-01.01.13en
103