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-   -   Electric Furnace Burned Element Wiring - Cause? (http://www.diychatroom.com/f17/electric-furnace-burned-element-wiring-cause-33726/)

Radioguy 12-14-2008 11:23 AM

Electric Furnace Burned Element Wiring - Cause?
 
4 Attachment(s)
Hi Folks:

First post here and I really need your help for peace of mind. I'm an electronically handy guy, but limited experience with high current AC devices.

This furnace was rebuilt 2 years ago with new sequencers, and 24 volt transformer. This summer, a tech came in and refurbished the air conditioning system.

At the moment, we have a -40 windchill and last night the furnace wouldn't respond to the thermostat ... furnace was on full. Tried fooling with thermostat programming and it wouldn't respond to ANY programing inputs. Removed and replaced batteries, same problem. Thermostat troubleshooting guide said to check furnace. I opened up the furnace for inspection and found several power wires from the sequencer to the element had burned through and there was lots of carbon from the insulation.

I have no heat at the moment and am using electric space heaters as primary heat til tomorrow when I can get it serviced.

I'll try to attach a couple of pictures to show the problem.

My question is what could have caused this degree of overheating of the wires to the point of flames?

If it were a simple failure, I'd have no reservations about replacing the sequencers and powering it up ... the burned wires give me second thoughts though .... what's your advice on how to handle this?

Thanks in advance for taking the time to help out and post.

Pictures below ... if this works .. LOL.

Regards,
Lee

yuri 12-14-2008 11:28 AM

Old age/vibration/poor connections. How old is the furnace? I have seen this LOTS in my 30 yrs on the job. If the furnace is over 20 yrs old I start recommending to my customers to replace them. I have seen a lot worse than that but it is an awfully expensive rewiring/repair job when that happens.

Radioguy 12-14-2008 12:59 PM

Yuri:

Thanks for your advice.

Small world ... I'm in St Francis Xavier.

Furnace is about 25 years old.

Lee

yuri 12-14-2008 01:06 PM

Then you are freezing your a** off with the rest of us. The only electric furnaces that parts are readily available for is the Nortrons. For under$3000 you can get a new one installed. Yours is toast IMO.

Cheers

Radioguy 12-14-2008 02:40 PM

Well, that's good news about the price. I had no idea they were so "reasonable" compared to a repair.

I should have done that when it was rebuilt 2 years ago .... what's the saying? ... Too soon we grow old, too late we grow smart.

Lee

beenthere 12-14-2008 11:35 PM

Poor wire terminal connections.

biggles 12-15-2008 06:55 PM

those slip connectotr and add some fan vibration even air moving over the element can cause the wires to draw over amps and melt them. as you see and notice where the melting started at the slip connector,and started to work its way onto the wire.....recut all the melted wires,and check all the connections right back into the CB panel for that heat.


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