Brand: SANYO
Category: Air Conditioner
Document Type: Manual
Language: EN
Manual for CM1812 / KMS0912
Uploaded: Nov. 21, 2025, 7:16 p.m.
- Room Temperature Control: The compressor cycles ON/OFF based on the room temperature sensor in the remote control unit. Room temperature and other information are transmitted to the indoor unit controller every 3 minutes.
- Automatic Time Delay: The control circuit waits at least 3 minutes after the compressor has been OFF before attempting to turn it ON. This protects the compressor from stalling against high refrigerant pressure by allowing internal pressure to equalize.
- Protective Shut-off: The control circuit switches the compressor OFF after 5 minutes or more of continuous operation as a protective measure.
- Thermo ON: Compressor turns ON when room temperature is above Set Temperature + 2°F.
- Thermo OFF: Compressor turns OFF when room temperature is equal to or below Set Temperature.
- Freeze Prevention: If the compressor runs for 10+ minutes and the indoor heat exchange coil temperature drops below 27°F, the compressor stops for at least 6 minutes.
- Fan Speed Auto (Indoor Fan): Fan speed does not change within 1 minute. Speed (H, M, L) is determined by room temperature relative to set temperature.
Troubleshooting and error codes
| Troubleshooting Item | Troubleshooting Steps | Diagnosis | Action |
|---|---|---|---|
| 6-2 Air conditioner does not operate (1) Circuit breaker trips (or fuse blows) | (a) When circuit breaker is set to ON, it trips in a few moments (resetting is not possible). | Possibility of ground fault. | Measure insulation resistance. If resistance value is 1MΩ or less, insulation is defective ('NO'). |
| (b) Circuit breaker trips in several minutes after turning air conditioner ON. | Possibility of short circuit. | Check capacity of circuit breaker. Measure resistance of compressor motor winding. Measure resistance of outdoor fan motor winding. | |
| (2) All unit (indoor and outdoor) do not run. | (a) Power is not supplied. | Check power supply. Is power being supplied to wall receptacle? | If NO: Circuit breaker is tripped. Reset breaker. If circuit breaker is not tripped: Power failure. Wait for recovery or contact power company. |
| (b) Check OPERATION selector switch in indoor unit. | Has OPERATION selector switch been set to ON position? | If NO: Set OPERATION selector switch to ON. If it still does not run: Switch Ass'y or PCB Ass'y in indoor unit is defective. If YES: IND LAMP Ass'y or PCB Ass'y in indoor unit is defective. | |
| (c) Check fuse F1 in indoor unit. | Check fuse F1 in outdoor unit for continuity. | If fuse blows: Measure coil resistance of relays RA and RB. | |
| (3) Neither indoor unit A nor compressor motor A runs. (Or, neither indoor unit B nor compressor motor B runs.) | (a) Check transformer in indoor unit A (or B). | Measure resistance of transformer winding. | |
| (b) Check fuse on PCB Ass'y in indoor unit A (or B). | Check fuse on PCB Ass'y in indoor unit for continuity. | If fuse blows: Measure resistance of primary winding of transformer. OK: Measure resistance of indoor fan motor winding. OK: PCB Ass'y is defective. | |
| 6-3 A particular component of air conditioner does not operate. | (1) Only compressor motor A does not run (or B). | Measure coil resistance of power relay in indoor unit. OK: Measure resistance of compressor motor winding. OK: Check compressor motor capacitor. | |
| Check overload relay. | It has tripped. | ||
| Is outdoor heat exchanger coil dirty or are there obstacles near air suction inlet of outdoor unit? | NO | ||
| Is temperature of compressor abnormally high? | |||
| YES | |||
| Refrigerant gas shortage. | |||
| (2) Only indoor fan does not run. | Check fan rotation. Turn fan gently once or twice by hand. | Fan cannot be turned. | |
| Check fan casing for foreign matter on inside. Fan motor burnout or foreign matter in bearings. | Remove foreign matter or repair. Repair or replace. | ||
| Measure resistance of indoor fan motor winding. | OK | ||
| Check fan motor capacitor. | |||
| (3) Only outdoor fan does not run. | Check fan rotation. Turn fan gently once or twice by hand. | Fan cannot be turned. | |
| Check fan casing for foreign matter on inside. Fan motor burnout or foreign matter in bearings. | Remove foreign matter or repair. Repair or replace. | ||
| Measure resistance of outdoor fan motor winding. | OK | ||
| Check fan motor capacitor. | |||
| 6-4 Air conditioner operates, but abnormalities occur. | (1) Poor Cooling | Check installation position of remote control unit. Does cool air from air conditioner reach position directly? | YES |
| Change installation position of remote control unit. | |||
| Are wide and narrow tubes between indoor unit and outdoor unit insulated? | YES | ||
| NO | Insulate wide and narrow tubes and then tape together. | ||
| Measure temperature of suction and discharge air of air conditioner. Temperature difference between suction and discharge air is large enough (approx. 18°F or more). | Temperature difference is small. Possibility of gas shortage. | ||
| Charge refrigerant gas (R22). | |||
| Check for clogging of air filter. | Air filter is clogged. | ||
| Clean filter. | |||
| Is fan speed set to LOW? | YES | ||
| Set fan speed to either HIGH or MEDIUM. | |||
| Review cooling load estimate, if performance of air conditioner is normal. | |||
| Reduce cooling load or replace unit with higher cooling capacity. | |||
| (2) Excessive Cooling | Is set temperature suitable? | NO | |
| Set temperature to higher value using temperature setting button WARMER. | |||
| Is remote control unit installed at place where it can detect room temperature properly? | NO | ||
| Change installation position of remote control unit. | |||
| 6-5 Indoor (heat exchanger) coil temperature sensor (TH1) is defective. | (1) Open | Even though the air conditioner does not thermo OFF, compressor and outdoor fan repeat ON for 10 minutes and OFF for 6 minutes. | |
| (2) Shortage | When dehumidified water freezes in the indoor coil, the freeze prevention function does not work. |