Troubleshooting Tips - Central Air Conditioners
Before you call for service …
Central air conditions will need some professional maintenance, but there are many minor problems that you can easily fix yourself. If your central a/c unit isn't working properly, look for the problem you're experiencing on this chart and see if it's a do-it-yourself job.
| Problem | Possible Causes | What to Do |
Condenser doesn't run |
1. No power. |
1. Check for blown fuses or tripped circuit breakers at main entrance panel or at separate entrance panel; restore circuit. |
2. Thermostat set too high. |
2. Lower thermostat setting 5°. |
|
3. Motor faulty. |
3. Call a professional. |
|
4. Compressor faulty. |
4. Call a professional. |
|
Uneven cooling |
1. Distribution system out of balance. |
1. Balance system. |
Inadequate cooling |
1. Thermostat set too high. |
1. Lower thermostat setting 5°. |
2. Evaporator dirty. |
2. Clean evaporator |
|
3. Unit too small. |
3. Replace with larger unit; call a professional. |
|
Unit doesn't cool |
1. Thermostat set too high. |
1. Lower thermostat setting 5°. |
2. Condenser dirty. |
2. Clean condenser coil and fins; if necessary, straighten fins. |
|
3. Condenser unit blocked. |
3. Remove debris blocking condenser; cut down weeds, grass, and vines. |
|
4. Evaporator dirty. |
4. Clean evaporator. |
|
5. Compressor faulty. |
5. Call a professional. |
|
6. Not enough refrigerant in system. |
6. Call a professional. |
|
Condenser unit turns on and off repeatedly |
1. Condenser dirty. |
1. Clean condenser coil and fins. |
2. Condenser unit blocked. |
2. Remove debris blocking condenser; cut down weeds, grass, and vines. |
|
3. Evaporator dirty. |
3. Clean evaporator. |
|
| A dirty evaporator is a common problem | ||
| Condenser fan runs, but indoor fan coil blowing warm air (compressor not running) | Condenser fan runs, but indoor fan coil blowing warm air (compressor not running) |
Check unit wiring and wiring |
Water drips from unit. |
Unit not properly leveled |
Level the fan coil unit. |
Condensate drain to condenser pan clogged |
Clean condensate drain. |
|
Noisy fan operation |
Fan striking |
Check for proper positioning and clearance fans. |
Loose fan or fan motor |
Check for fan tightness on shaft. Check for loose fan |
|
Outside air entering the unit |
Check for proper closing of outside air doors |
|
Air across condenser restricted |
Check condenser air |
|
Dirty or blocked condenser |
Check condenser for blocked dirt. Clean it |
|
Compressor or refrigerant system faulty |
Call a professional. |
|
| Evaporator ices over
|
Clogged or dirty air filter |
Clean or replace air filter. |
Evaporator fan motor tripping on overload |
- Check for overheated evaporator fan motor and tripping off on its internal overload / Call a professional. |
|
Unit operating at too low room temperature |
If room temperature drops below 70F, the evaporator may ice over. |
|
Unit will not run
|
Blown fuse / breaker trip |
Check fuse / breaker |
Broken or loose wiring |
Check voltage at switch. If there is proper voltage at switch but no continuity thought it, replace switch / Call a professional. |
|
