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justdifferent 07-02-2012 10:24 AM

Outside a/c unit not working
The outside A/C unit quit but the inside fan is blowing when the t-stat calls for unit to cool. Copper lines are warm to the touch. Perviously on Saturday I heard a high pitched whine coming from the outside unit but it continued to work but only blew out hot air from the inside vents and then it quit for good. When I touch the outside unit after setting the T-stat to call for cooling I can feel a slight vibration but the fan doesn't spin and the unit doesn't come on. On Wednesday prior, the unit's overflow pan was collecting water so I shut the system down and let it thaw. It worked until Saturday. Exact same thing happened last year when temps hit the triple digits! Soonest service call is Thursday...could this be a diy fix because I'm up to the challenge if I can find out what the problem is and then find the parts. Help please! :(

autx790 07-02-2012 11:08 AM

I've had a few issues with my ac that have similar indications to what you describe. I dont know enough to guide you but here's what i can tell you. If yours isn't freezing over, than the only trouble i had that was close to yours is i had a loose wire in the thermostat that caused the heat to operate when it was set on cool. There are a lot of smart people on here who should be able to guide you through a troubleshoot. Hang in there. My ac is out too till friday. Thinking i'm gonna go to lowes to get a $99 window unit.

Sorry, i reread your post and i dont think my comment above applies. What turned out to be the problem last year?

justdifferent 07-02-2012 11:57 AM

Thanks...I thought about getting a temp unit as stormed last night and cooled off considerably from the 89 degrees showing on the t-stat downstairs...upstairs was unbearable during the day. Last year the technician replaced the board in the furnace I believe but it was because the inside blower stopped working. It was working sporadically and by the time the tech got there it was working ok until it finally quit altogether and they were able to locate the problem after about three trips out...I'm sure they thought I just wanted attention until it finally broke :-)! At another time last summer during the heat wave, the outside unit also quit and it turned out to be a part where a bug had crawled into the contacts and shorted it out. Don't recall what the part was called but the tech said they were replacing these with sealed units that insects couldn't get into so I thought maybe that wouldn't be the problem this time; but am beginning to wonder if this unit just can't take the triple digit temps and running all the time to try to cool the house down to the 75 degrees I have the T-stat set to during the day. At night I turn it down to 68 and it runs a long time trying to get there. Which is why during triple digit temps I would close the vents downstairs because the upstairs would still be warmer after the downstairs struggled to reach the t-stat temp but that was obviously a bad move since it led to freezing up of the coil.

Doc Holliday 07-02-2012 11:59 AM

Add a return air or two upstairs.

justdifferent 07-02-2012 12:43 PM

Repair service said they could get someone out to my house, tomorrow hopefully... I'll ask them what adding a return means...and will post back when they diagnose the a/c problem. Thanks all!

autx790 07-02-2012 01:31 PM

Adding a return would be adding a duct to bring air from upstairs back to the unit. (the duct you replace your filter at).

Which by the way...i'm only assuming your filter is clean.

In looking for solutions to my problem i read where closing off a lot of your vents could cause the unit to have some problems. I'd ask him about that too.

and...68deg? I've never had my unit take my air that low (unless it's winter time). My upstairs unit is set to 86 and it runs all day now with the heat we've been having. Of course i do need to finish doing some repair work to the house :)

justdifferent 07-02-2012 03:45 PM

Air filter is clean. Learned that lesson 10 years ago when my old a/c unit overflowed the drain pan in the attic and caused a good chunk of the ceiling to fall down. When I replaced the a/c a few years later they didn't hook up the float switch but I had it done last summer. Good thing because when I noticed water dripping from the overflow pipe last week and checked the attic drain pan it was 3/4 full.

It was during higher than normal temps that I closed off the downstairs vents to force more cool air upstairs which led to the coil freezing up. It seems that I can close the vents downstairs during more moderate temps and its not a problem but when its in triple digits and the unit runs longer it may then become a problem...just a theory, not sure.

But anyway, I grew up without air conditioning and it didn't kill me so I guess I can make it a few days without it...:no:

justdifferent 07-04-2012 02:21 PM

Technician came this morning and replaced the dual run capacitor, an inch and a half or so cylindrical part. Took about 10 minutes tops.

The t-stat read 86 this morning around 11:30 and 3 hrs 45 mins later it won't go any lower than 80 deg so I reset the t-stat from 75 to 80 and its cycling on every few minutes; outside temp is about 94 now.

Right before it stopped working Saturday it emitted a high pitched hum that's still there after the fix though. The tech couldn't hear it but being used to the unit's normal sound, I could hear it clearly.

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