Warm air was coming out of my AC vents yesterday. I went to the outside fan/compressor unit and found it not running. I went to the breaker box and found the 40A breaker tripped. It tripped again immediately when I tried to reset. The unit it about 15 yrs old. Is it likely time for a new compressor? If so what should I expect to pay for a new one? The unit is a 1.5 ton trane high efficiency XE900.

Thanks!

 

You're a long way from replacing the compressor yet. First thing you do is to set the thermostat to off and reset the breaker. Does it still trip? If it does then you are looking at a short with burned wires, smoke, and smell. visually check everything real close. You should find it visually.

If it does not get someone to help you and go stand beside the condensor while someone sets the thermostat to cool. You will likely see the fan come on and hear the compressor try and start, and then the breaker trips. If that is the case then you are likely looking at a capacitor replacement. $15 or so.

If the compressor starts but the fan does not even attempt to start then you may be looking at a fan capacitor. $10 or so.

If you never hear a sound out of your compressor then you may be looking at something more critical, but lets check the wiring and caps for now.

There is really no way for a DIY'er to check the capacitors except for visually. Look for bulging, discolored, or leaking. Maybe even contacts loose from the base.

If you can find someone to even sell you the capacitors they are usually cheap enough to replace them just to see if that fixes it. Otherwise you are probably looking at calling in a pro.

 

I set the thermostat to off, reset the breaker, waited a couple hours, then turned the thermostat back on and the whole house breaker tripped in addition to the breaker for the outside unit. I had someone outside but the compressor and fan made no attempt to start. I did a visual inspection and saw no evidence or smell of a wiring short. Looks like I'll be calling a pro. Thanks for the help!!

 

You need a multi-meter and the know how to check the compressor. You've for sure got a direct short to ground.

Do not even consider replaceing just the compressor in a 15 y/o unit if that's what the diagnosis ends up being. At that age it's time for a new system all together.