House AC Problem

[Russ Filtz]

Split unit. My heat/ indoor fan work fine, but today I tried the AC and get nothing. Circulation fan runs, but the outside compressor just sets there. No fan, no compressor, nothing. Usual suspects?

1 - low freon
2 - bad compressor (would outside condensor fan run if so?)
3 - bad condensate overflow switch

Any others?

[Dave Johnson29]

1 - low freon
2 - bad compressor (would outside condensor fan run if so?)
3 - bad condensate overflow switch


Check the main 220v breaker on the main panel of the house.
If the outside unit has a control box, start with the fuse or breaker in it.
Check for voltage with a meter in the control box.
Outside fan may 110v which it gets from one leg of the 220v and Neutral.
No point trying to guess what might be wrong.

[Pat Germain]

If the outside is completely dead, it probably is just a breaker or fuse. The outside unit probably has it's own breaker nearby. Trace the electrical line from the unit back to the house. It will probably lead to a small breaker box attached to the house.

[Russ Filtz]

It IS popping my AC breaker in my main house box! Would there be another breaker AT the unit? Good call. Bad breaker or something more serious?

[Tom Godley]

Normally, if it is low on a charge, the cutoff keeps the compressor off - but the outside fan will still run. If the compressor is stuck -- you normally will hear a hum and a click -- but the outside fan will still run.

Some units have a breaker in the outside unit -- also fuses or a breaker in the outside disconnect as well as at the panel box.


On the control circuit it can be anything from the thermostat or relay - even a broken wire.

Do you hear any click at the outside unit when you turn it on??

[Russ Filtz]

Been doing a 1-man check right now, so don't know what happens when I flip the switch.

[Tom Godley]

OH - :(

No - the control is working and the power is working. You have a short.


If it happens immediately you have a short -- may be either the compressor or the start capacitor.

[Dave Johnson29]

Been doing a 1-man check right now, so don't know what happens when I flip the switch.

If it is tripping the main breaker in the house, then don't bother looking for a fuse or breaker on the outside unit. It is a dead short somewhere.

Could be water in the panel, be VERY careful when messing with that.

Unless you are VERY comfortable around live 220v call the repair guy.

[Ken Fitzgerald]

As Dave stated....be very careful.

Most systems will still have a breaker/fuse near the outide compressor unit.

With circuit breaker tripped in your breaker box inside......find that outside fuse panel. Some even have a handle....switch on them...... either turn off the switch if so equiped.....or remove the fuse........

THEN reset the breaker in your breaker panel......

If the breaker trips then.....you have shorted wiring between your breaker panel and the switch or fuse box outside.

If it doesn't trip......get a repair man as you could have a shorted motor etc........

[Russ Filtz]

Thanks, not shorting the MAIN breaker, it's the AC breaker in the main panel. I'll try the outside box (with the breaker flipped!) tomorrow in daylight. The breaker doesn't flip on it's own all the time, just when I turn the AC on at the thermostat.

[Pat Meeuwissen]

Russ, the reason it only trips when you turn on the thermostat is because thats what pulls in the relay to turn on the compressor et al.. that in turn will trip your breaker if there is a problem.

To my knowledge the fan on any 240 volt AC compressor will also be 240 volt and not run seperately, but an older unit could have a transformer to convert 240 to 120 volt. This would be counter intuitive as it would be more efficient to run the fan at 240 volt.

As stated before, and judging from your questions you don't seem to be qualified to work on electrical components, please call a technician. If it turns out to be a compressor you would need specialized tools to replace it, and buying them would cost way more than what you would save trying to do it yourself. Please proceed with care. Pat

[Al Willits]

Outside unit usually just needs to be a disconnect, some put breakers there, but depending on your local code, usually a breaker isn't needed.

It could be shorted wire, bad condensor motor/cap, compressor/cap for a start.

Pretty rare we see a 110 condensor fan.

Pull the breaker then open the axcess pannel and look for burn spots, also burn marks on the compressor leads, after that, get help.

Al

[Russ Filtz]

Russ, the reason it only trips when you turn on the thermostat is because thats what pulls in the relay to turn on the compressor et al.. that in turn will trip your breaker if there is a problem

Yea, I understand all that. I've wired 240V subpanels, circuits, etc. Just clarifying what is actually happening and there wasn't some crazy failure bypassing my thermostat. Plus I haven't been able to inspect the compressor outside to see what's really out there since it's been raining heavily last 2-days! Some of the comments made it sound like there might be two breakers on the circuit which seemed out. It's more likely just a cutoff outside.


To my knowledge the fan on any 240 volt AC compressor will also be 240 volt and not run seperately, but an older unit could have a transformer to convert 240 to 120 volt. This would be counter intuitive as it would be more efficient to run the fan at 240 volt.

Again, I'm not describing it properly I guess. The fan that runs is the inside unit circulation fan, not the fan on the compressor unit outside.


As stated before, and judging from your questions you don't seem to be qualified to work on electrical components, please call a technician. If it turns out to be a compressor you would need specialized tools to replace it, and buying them would cost way more than what you would save trying to do it yourself. Please proceed with care. Pat

If it's the compressor I will certainly get help. Motors/fuses I can handle. Just replaced my pool 240V motor not long ago.