Outside York A/C suggestions

[jackrabbit]

Arrived home today to 1500 sqft, 90 degree oven My central heat and air was blowing but not cold. Unit outside wasn't making any noise whatsoever. I powered it off and let it set for a while. Shut off the power and went out after dark to take another look (was searching for a reset). Turned off the breaker outside and pulled off a corner panel to expose some wiring, but no visible reset. Was dark so didn't feel daring enough to pull of any other panels (nothing else looked easily accessible). Turned breakers back on inside and out and kicked the thermostat back on. The air started blowing again inside, but the unit outside - still nothing. Well not exactly nothing. It hums steadily, then after 15 - 20 seconds a different, slightly louder hum kicks on (the fan trying to turn?) and then stops after a second or so. I let it do this for a minute or so and shut it back off.

I can't really afford to call the technician right now, so any help anyone might be able to give me in diagnosing this would be wonderful. I figured I'd turn the power off and try giving the fan a spin to see if the bearings are seized up. Other than that I've got no idea. I'm afraid I don't have much experience here.

[HayZee518]

the outside unit houses the compressor and condenser fan. there should be a disconnect located within sight of the unit. going in and coming out of the remote unit should be a large tubing and a smaller tubing of copper. large one is the [suction] line and the smaller is the high pressure line. high pressure line goes to the A coil or evaporator in your discharge air duct. the [suction] line is the return to the compressor. the refrigeration system is a closed loop. shut off the disconnect near the outside unit and try to spin the fan. if it spins ok, then the bearings probably are ok. open up the control box and look for two contactors. one will be for the compressor, one will be for the condenser fan. look to see if there are any resets on these. press to reset. also check to see if there are any hi and lo limits. these may have a reset on them also.

[jackrabbit]

Small success?

Thanks so much for your prompt reply! The fan turns freely and I pushed the only reset I could find. I kicked the unit back on and still the same thing. I used a screw driver to spin the condenser fan while it was humming and I managed to get the fan to keep spinning (although I doubt it will start on its own again) I continue to hear a louder hum every so many seconds from what sounds like the region of the compressor. Neither the air or the copper tubing seems to be getting cold either (but it's only been on for about five minutes). Do you have any idea of anything else I might be able to try? (or least a rough idea how much I'm going to be spending?) Thank you again. I greatly appreciate it.

[jackrabbit]

Fixed

Just wanted to post and let you know that I got it fixed. The capacitor was blown. Took it up to the local HVAC guy and he tested it and gave me a new one. It's a different size than my old one, but he said it wouldn't hurt anything. Thanks again for your help.

[HayZee518]

OK the value of the capacitor can be higher than what was originally used. the voltage rating has to be close to what you input voltage is. the capacitor's function is to induce a voltage in the fan's or compressor's start winding to get it spinning.

[suprheat]

Ooops! HayZee518 has got it backwards... the mfd rating of the cap should be the same and the voltage rating can be higher than original (not lower). It also sounds like it is a dual cap meaning it has two mfd values- one for the fan and one for the compressor. If you don't match the mfds you will experience premature failure of whichever component is not matched to original mfd value.