New Central Air unit shutting off after an hour max


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Old 07-17-13, 08:42 AM
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New Central Air unit shutting off after an hour max

Greetings All -

we put in a new unit last summer - worked fine all summer and first month of 2013. Unit was serviced end of last season.

2 Days ago, outside fan stopped (inside fan continues to blow non-cold air).

we checked the breakers (flipped back and forth); unit starts again - but only last between 10 minutes and an hour, maximum, of blowing cold air.

what are possible issues?

on the phone, people have told us it's electrical - not enough power, but why would it be fine last year?

also, we added duct work so upstairs of our (small) cape cod-style home gets cool air - Does adding duct work create additional demand for electrical power? Would this cause increased demand on electric - and hence, cause the shut-off after an hour?

Other guess we heard was that unit was maybe "Overheating" - aren't these units built to operate in the summer???

Unit we installed was intentionally large enough to eventually cool the upstairs.

Many thanks.
 
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Old 07-17-13, 09:26 AM
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What does the guy say that installed it last summer? He won't come out and take a look at it? If not, then it's going to take a volt meter and some knowledge on how to trace the problem down. Could be anything from a weed whacker hitting a low voltage wire to a safety in the system not allowing it to come on. Not sure why a new system would be serviced last year if it was working fine. More info would help.
 
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Old 07-17-13, 11:00 AM
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person who installed it no longer available.

we serviced it not b/c anything was wrong, just annual maintenance.

Unit DOES come on - and blows cold air for anywhere between 20 minutes to an hour and a half - and then shuts down.

We turn it off at the thermostat - wait an hour or 2, turn it back on, and again it works for a limited time.

is it possible for a Central Air unit to overheat?

does added duct work create a demand for greater electricity?

if that's the case (greater electrical demand) mean we have to increase amp system, from 100 to 200?

We had a man look at it yesterday and his volt meter indicated no problems with unit.
 
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Old 07-17-13, 01:04 PM
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Update - Issue Seems to be Resolved - Here's How:

We had an electrician REPLACE the outside detachable fuse from 20 amp to 30 amp - which is what new central unit was supposed to be on in the first place.

He said the wrong-sized amp was causing unit to overwork - and on hot days, it would simply shut down.

He also replaced wiring from 14 to 10 gauge.

Apparently, he indicated, we were lucky that machine was able to get through last summer with wrong amp size fuse box and wire gauge.

Keep your fingers crossed - so far so good.
 
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Old 07-17-13, 01:54 PM
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If the unit pulled more then 20 amps, the fuse would blow, not the unit.
It's possible the wires were burning up, 14 - 10 is a big jump. You might have just saved your house from burning down. Hope it's resolved the issue.
 
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Old 07-17-13, 03:14 PM
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Glad you got it fixed and hopefully someone else will see the moral to the story. Have a reputable company install your system so that if you have a problem a year later, that they can take care of you to make you a happy customer. 14 gauge wire??? OMG
 
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Old 07-17-13, 03:26 PM
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I will add, I have seen electricians wire jobs we did on 2 ton systems with 20 amp breakers and 12 wire. Had my doubts but they said it was code as long as the run was close....I prefer 10 mininum
 
 

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