AC's on but the outside fan is not running

[01tj]

Our house got pretty hot today and we noticed that the fan on the outside (compressor) of the house is not running. I checked the fuse box and everything looks okay. What else is there to look for

[barry2952]

There will be a pullout disconnect near the a/c unit. Sometimes this box contains fuses. Start there. There's also a small 2-wire cable that turns the unit on. Check for critter damage.

If you touch these small thermostat wires together in the unit's junction box the unit should come on. If it does you may just have a bad thermostat.

[Rockhead261]

If you touch these small thermostat wires together in the unit's junction box the unit should come on. If it does you may just have a bad thermostat.

No. You will short the control circuit and blow a fuse (if you're lucky) or fry a costly control board.

OP, you mention the outdoor fan (condensor) is not running. Is the compressor inside the condensing unit coming on? Do you hear a 'click", but nothing happens? Do you feel a great deal of heat emanating from the unit? If your condensor fan has died it is likely the compressor will run for a short time before overheating and shutting down. The unit will be hot and may attempt to restart once it cools. A bad condensor fan is not a death sentance and is fairly easy to replace.

If nothing is happening it could be one or a combination of scores of problems. Check for the obvious first - a tripped breaker may not appear tripped. Turn it to the 'off' position, then back on.

Check for power at the outdoor disconnect with a multimeter. If you're not comfortable doing so, stop and proceed no further. Call in a tech.

If there's power, confirm that your control circuit is sending 24VAC to the condensor. Some older condensors have their own transformers and provide control power for the system. Most newer systems have the control transformers inside the furnace/airhandler. DO NOT touch wires together unless you know exactly what they are.

No disconnect power = start ringing wire.

No control voltage = start ringing wire and checking indoor controls.

Power at the disconnect and control voltage = trouble inside the condensor. Shut off the power and start digging.

[barry2952]

No. You will short the control circuit and blow a fuse (if you're lucky) or fry a costly control board.

In all cases? My bad.

[PlatinumGLS]

This has happened to me...was the contactor. A $20 part that can be swapped out in 20 minutes. A lot of times, you can look at it and tell right away if that needs to be replaced.

[Rockhead261]

This has happened to me...was the contactor.

Very common failure and easy DIY. I replace mine every 5-7 years as PM, along with the run capacitor. Cheap insurance. Remember; A/C units only break down during heatwaves.

[PowerDubs]

Had my 'contactor' fail as well last year. Cheap and easy DIY fix.


- Josh

[e_andree]

contactor on the right..capacitor on the left, correct? I had the exact same issue as OP.....ended up being bad capacitor...35 dollar part.

http://r-a-y.org/2010/07/ac-contacto...ch-repair.html

[barry2952]

On a metal cased capacitor you'll note a dab of solder near the terminals. When assembled the lid is flat. That solder connection contains a fine wire that's soldered in place. If the capacitor fails the lid will bow, breaking the tiny wire internally. We find capacitors can swell from over current situations and lightning strikes. They are also sensitive to heat. We try and keep them as far away from an HID fixture's ballast as possible.

[Rockhead261]

contactor on the right..capacitor on the left, correct?

Correct.

[baryyknowseverything]

There will be a pullout disconnect near the a/c unit. Sometimes this box contains fuses. Start there. There's also a small 2-wire cable that turns the unit on. Check for critter damage.

If you touch these small thermostat wires together in the unit's junction box the unit should come on. If it does you may just have a bad thermostat.

In all cases? My bad.

On a metal cased capacitor you'll note a dab of solder near the terminals. When assembled the lid is flat. That solder connection contains a fine wire that's soldered in place. If the capacitor fails the lid will bow, breaking the tiny wire internally. We find capacitors can swell from over current situations and lightning strikes. They are also sensitive to heat. We try and keep them as far away from an HID fixture's ballast as possible.

[GeoffD]

Reported.

[robhurlburt]

There will be a pullout disconnect near the a/c unit. .

this happens to me every now and then. all i do is pull that disconnect for 1-2min and plug it back in. it always fixes it

[vdubman1]

On a metal cased capacitor you'll note a dab of solder near the terminals. When assembled the lid is flat. That solder connection contains a fine wire that's soldered in place. If the capacitor fails the lid will bow, breaking the tiny wire internally. We find capacitors can swell from over current situations and lightning strikes. They are also sensitive to heat. We try and keep them as far away from an HID fixture's ballast as possible.

The top of the cap isn't always bowed out if its bad, I have seen a few that looked normal but when I checked it with my meter it was bad.

OP did you figure out your problem yet?