Heating, Air Conditioning, Fridge, HVAC/Trane XR80


utah-ike wrote at 2007-12-03 16:31:36
I ran into this same thing 3 days ago. It seems silly that they do not explain this in the users manual...I guess it is a conspiracy to get you to call a contractor.

This is VERY common on this series of heaters. What has happened is the Overheat circuit has been tripped. Ours tripped when the power went out during a preheat cycle of the heater. It does not take much to trip these things.

This fix is going to sound silly and almost too simple. You will be frustrated that you spent the night in the cold over such a silly fix...I did!

OK...to fix, remove the front panel from the furnace. You will see a 2 inch by 3 inch circuit board with two wires attached to it. This is located on the firewall right behind the fuel shutoff valve. Take a screwdriver and place the tip on the top screw on the circuit board listed above. Take another screwdriver and give the other screwdriver 3 good solid knocks. Put everything back together, turn your furnace on and enjoy the heat.

The 3 knocks make the sensor switch fall back into place, allowing the circuit to close.

Pretty dumb huh? Wouldn't it have been easier for Trane to put a little button on the circuit labeled "RESET"? Man I hate product designers...they should be forced to use this stuff for a year in their own home.

Now, that being said...If you continue to trip the circuit, or you have no explanation why the circuit tripped..you should really call a tech to come and examine the airflow for possible obstructions.

Good luck.

K L wrote at 2008-02-11 21:18:37
Works like a charm. Sounded silly, but got the job done. Thank you for this post.

bnorris wrote at 2010-01-27 13:29:55
I scoured the web all day trying to figure out how to reset the sensor and finally came across this little trick.  I couldn't believe it but it worked! Thanks, you saved me some money and from another night in the cold!

Scott H wrote at 2012-11-25 20:28:41
Hard to believe but it actually works.  I was doubtful but was willing to give it a shot.  5 hours of a cold house solved with 3 hits of a screwdriver...cost me only the frustration of a furnace that wasn't working!  

LMF wrote at 2012-11-27 18:35:01
I changed my air filter (as it was filthy) and still didn't work... figured I must need to "reset" something so I found this posting... WORKED LIKE A CHARM!  Can't believe it, what did we do before the internet? Probably paid a contractor $200 to come bang on the bolt with a screwdriver!

Chris wrote at 2012-12-30 04:00:28
I can't thank you enough for this. We have a newborn and couldn't get anyone to service our furnace in the middle of the night. It's 10 below zero and felt colder inside. Your trick worked perfectly. We're so grateful!

DJ Phobia wrote at 2013-11-26 20:56:53
It still works GREAT! You saved me a service call!!!!

az wrote at 2013-12-29 18:01:17
I can not believe it worked.. Three bangs and done.

Only thing i would add to the answer is the picture of the 2 X 3 circuit board for the non-mechanically inclined.

Thanks very much!!


pjg wrote at 2014-01-29 02:55:24
I must absolutely thank utah-ike. Furnace was responding to thermostat, blower working fine, check the earthquake switch, gas being delivered, igniter glowing...and then no gas/heat. 4 flashes. High limit "trip." What? Schematic is garbage. No switch to reset on board. Nothing.

Now what?

Search. Finally end up here. Hit the circuit board? Really? It already appears built by shoddy Radio Shack parts in someone's outhouse. But what else can you do? It's January. I don't want to be told to purchase a new board; especially, when I don't trust that it'll fix it (I mean, if this one's junk, the next one...). And look up the cost. No.

I follow utah-ike's instructions to hit the circuit board. Yeesh, but ok. Push in the cover actuated black switch. Everything whirs up from the thermostat call. Igniter glows...AND GAS FLOWS!

Hallelujah. But seriously, this thing is garbage. Trane can go shove it. Manual is absolute garbage. Nothing explained, nearly zero troubleshooting value.

Anyway, do what utah-ike states. It works, weirdly. Thanks utah-ike. Wherever you are in this great Internet land, I thank you greatly.

stevethesleeve wrote at 2014-03-09 16:16:29
WOW! It worked on my Trane XR 80 manufacture date 8/2004 furnace. It's Sunday morning, I wake up to the furnace blowing cold air and the red indicator light blinks 4 times. I tapped the top bolt and wallah I have heat! I called my HVAC guy 2 hrs ago (remember Sunday morning 9am) and now it's 11 and no return call. Thank God I came across this site! I will wait and see now the furnace operates through the day before having them come to the house, if at all. THANK YOU!

SewJude wrote at 2014-03-30 21:04:09
FANTASTIC!!!  Thank you so very much for posting this easy fix.  It worked like a charm.  We had a tech to the house 3 weeks ago for the same symptoms and he charged upwards of $400 so I was reluctant to call him again. I am ever thankful for coming across this site. God Bless

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Tony Duggan


any question on residential heating, air conditioning, Or electrical. no boilers - sorry


Hold current state licenses, worked in the installation, repair, & design of HVAC systems for 20 years.

Air Time 500, Condition Air Assoc. of Georgia

BBA - Management, current state licenses, 8 hours of yearly education, many classes on all aspects of design

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