Electric Furnace Quit


  #1  
Old 02-02-20, 01:59 PM
K
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Electric Furnace Quit

I have an electric forced-air furnace under the house that quit working. I noticed a burned electrical smell in the bedrooms and noticed the furnace would no longer call for heat from the thermostat. The breakers in the panel in the garage did not trip and the breakers on the furnace itself did not trip. I crawled under the house and opened the furnace but didn't see anything burned looking. The filter was the dirtiest filter I have ever see. I don't know how any air was getting through it. We bought the house two years ago. The house was built in 1976 and I don't think the furnace was any younger. Any Ideas? The plan is to get a new unit soon, but I am wondering if there are any parts under $300 I can throw at it. Thanks
 
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Old 02-02-20, 07:01 PM
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Check for power with your meter.
I don’t see any manual limits in the photos.
Will the blower operate?
I cannot suggest any parts without first diagnosing the problem. And it would be unwise to blindly change parts trying to chase the problem.
 
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Old 02-03-20, 11:12 AM
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These electric furnaces are very basic but can be tricky as well as dangerous to troubleshoot.
I've labeled your picture......

1A+1B is one breaker.
2A+2B is other breaker.
You should measure 240v between the 1A and 1B connections as well as the 2A and 2B connections.
The four SS devices are safety stats. They should check as normally shorted. If they are open they are bad.
The C devices are the cycling stats and should also check as shorted.
The E terminals are the heating element.
The four SQ devices are the sequencing relays.
When 24vAC is applied to them they operate and switch the 240v to the heater elements as well as the blower. These are the hard devices to check as they are easy to short when testing. The 24vAC to operate the sequencers comes from the W1-W2 connection at the top of the picture.

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