# Central Air won't come back on after power outage



## rws762 (Jun 15, 2014)

Tonight we had a brief power outage (approx 10 sec.), afterwards I noticed our central a/c would not come back on. after checking some online forums I reset the A/C breaker and turned the thermostat off. After 30 min I tried turning the A/C on and the compressor & fan outside run ok, but the blower fan inside does not. Any suggestions? BTW it is a Carrier unit approx 10 years old, I also reset the furnace breaker and will leave both off overnight to see if that helps. If not I guess it's serviceman to the rescue. Thanks in advance.


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## del schisler (Aug 22, 2010)

rws762 said:


> Tonight we had a brief power outage (approx 10 sec.), afterwards I noticed our central a/c would not come back on. after checking some online forums I reset the A/C breaker and turned the thermostat off. After 30 min I tried turning the A/C on and the compressor & fan outside run ok, but the blower fan inside does not. Any suggestions? BTW it is a Carrier unit approx 10 years old, I also reset the furnace breaker and will leave both off overnight to see if that helps. If not I guess it's serviceman to the rescue. Thanks in advance.


if it has a heat tape in the unit , their may be a set of breakers for that also, the fan run's off of 1 leg of the 220 , one side may be triped ? does it get cold in side of the plenum box. i has to get so cool inside before the fan for AC come's on, their should be a slide switch to set the fan to automatic or run, try the fan in the run it should come on than ? if not than i guess a furnace comp. is next .my 2 cents


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## rws762 (Jun 15, 2014)

could you please clarify for me what is the plenum box (I'm non-HVAC person)? Answering the question about the fan I set the fan switch on the thermostat to run and nothing. Usually both come on together. It looks like the compressor/fan unit outside is ok but the blower fan inside isn't working. Is it possible there is a reset switch inside? Also what is a heat tape?:huh:


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## rws762 (Jun 15, 2014)

I did reset the breakers for both the AC and furnace I might add.


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## yuri (Nov 29, 2008)

You may have had a power surge/spike or brownout/low voltage and the circuit board got damaged. Need a Pro to find out.


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## rws762 (Jun 15, 2014)

that's what I was afraid of, thanks.


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## clocert (Oct 14, 2010)

Check the fuse on control board.


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## yuri (Nov 29, 2008)

Yep, there is a purple 3 amp GM plastic auto fuse on the board. However if the fuse was blown the outdoor unit should not run unless the contacts in the contactor got welded together.


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## Thurman (Feb 9, 2009)

And- -check your thermostat closely. I found out that mine has an internal circuit breaker just for the t'stat. There is a tiny hole in the face of the t'stat but you have to open the door for setting the temps to find it. Anytime we have a hard T'storm/lightning the t'stat seems to trip. A paper clip does the job to reset the t'stat.


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## biggles (Jan 1, 2008)

verify the condenser isn't running with the stat in the OFF on system...if the Fan runs when you put the stat to FAN/ON you have 24V control..... if no board and or fuse is shot.at least it isn't the condenser running with a welded contactor....seeing any ice on that insulated line outside or into the furnace?


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## rws762 (Jun 15, 2014)

The outside unit compressor/fan is running ok and the line running in from the outside gets cold when the unit outside is running and it sounds like something inside is trying to come on, but zilch. The blower fan inside will not run even when I kick the t-stat fan control to ON. Also someone mentioned a purple 3 amp GM plastic auto fuse on the control board. I'm a lay person. I know where the 2 access panels on my furnace are would this be located there?


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## ben's plumbing (Oct 6, 2011)

rws762 said:


> The outside unit compressor/fan is running ok and the line running in from the outside gets cold when the unit outside is running and it sounds like something inside is trying to come on, but zilch. The blower fan inside will not run even when I kick the t-stat fan control to ON. Also someone mentioned a purple 3 amp GM plastic auto fuse on the control board. I'm a lay person. I know where the 2 access panels on my furnace are would this be located there?


 yep on the lower compartment control board.. but as yuri mentioned ...if fuse on control board is blown means no 24 volt to stat which would mean no 24 volt to a/c contactor ...go ahead and check but seems like something is up...agree with yuri may need a pro to see what may have happened....sorry...


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## rws762 (Jun 15, 2014)

never mind I found the fuse, it's fine


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## yuri (Nov 29, 2008)

You should call an authorised Carrier or Bryant or Payne dealer (Carrier owns both) and get them to check the heat exchanger if it is a high efficiency furnace. There was a class action lawsuit for defective /leaking water heat exchangers on some of them and only they can deal with it. Have to pull out the fan to check them and it is difficult.


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## rws762 (Jun 15, 2014)

I wish the issue could be blamed on that, I think it's due to a power surge hitting the circuit board. I ran part of the A/V operation at our church this AM, it's about 5 min. walking distance from our house, and they had some stuff affected by the power surge. Oh the joys of being a homeowner.


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## yuri (Nov 29, 2008)

I meant you may have another problem which they can check while they check the board. If it is leaking it is good to find out.

Yeah, power surges are nasty.


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## rws762 (Jun 15, 2014)

The furnace is Bryant, approx. 18 yr old, not sure if it's high efficiency or not


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## Doc Holliday (Mar 12, 2011)

outside condenser would not run at all if fuse were blown, Where do you thing 24 volts comes from, what the fuse protects?

Is this electric heat or gas?

with a fuse I'd suspect gas. If that's the case or in any case you need a multi meter to diagnose. 

time for a new system!!!


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