Trane "thermal protection device open" error

[AJ]

I have a Trane XE 80 (1997 model) which stopped burning gas recently.
Unless I turn it off at the wall control, the fan runs continuously,
trying to circulate non-existent heat.

The diagnostic LED flashes 4 times when the fan comes on and the chart
says "thermal protection device open." The unit is cold with no
evidence of gas reaching the burners and no gas smell.

I see two modules, each with two yellow wires, located on both sides
of the gas ports. Are those heat sensors? Below are some pictures of
the unit that might help. Thanks for any advice if this is
user-fixable.

http://expresswave.tripod.com/misc/Trane_XE_80_parts.jpg
http://expresswave.tripod.com/misc/Trane_XE_80_codes.jpg

AJ

[Todd Legere]

Check and make sure your filter is not plugged.

toddl...@hvacmechanic.com

"AJ" <aj00...@tripod.com> wrote in message
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[CBHVAC]

"AJ" <aj00...@tripod.com> wrote in message
news:8ip71u8cvom26uboh...@4ax.com...

> I have a Trane XE 80 (1997 model) which stopped burning gas recently.
> Unless I turn it off at the wall control, the fan runs continuously,
> trying to circulate non-existent heat.

No..its doing as the control is programmed to do in the event of an overheat
condition..
It knows there is either, no heat there, or too much for the thermal limits.

>
> The diagnostic LED flashes 4 times when the fan comes on and the chart
> says "thermal protection device open." The unit is cold with no
> evidence of gas reaching the burners and no gas smell.

Again..there will not be with a roll out switch tripped.

>
> I see two modules, each with two yellow wires, located on both sides
> of the gas ports. Are those heat sensors? Below are some pictures of
> the unit that might help. Thanks for any advice if this is
> user-fixable.

Might be...check your air filter...dirty? Replace it.
If not, call the installing company to have them check it so you can get
your heat back. The sensors are tripped for a reason, and no..its not owner
repairable. While you might be able to get it to run, you have not found and
repaired the condition that caused it.

[Scott Eslick]

Could this furnace also have the radiant heat sensor????
--
Scott Eslick
scott...@email.com
ICQ 3889251

"AJ" <aj00...@tripod.com> wrote in message
news:8ip71u8cvom26uboh...@4ax.com...

[AJ]

On Sun, 9 Dec 2001 18:43:18 -0500, "Todd Legere"
<toddl...@sympatico.ca> wrote:

>Check and make sure your filter is not plugged.

Thanks, I think you nailed it. Lazy cleaning in recent months let
impacted dust reach critical mass.

Now the question is, how do I reset the thermal protector? It doesn't
seem to be kicking back on automatically.

AJ

[AJ]

On Sun, 9 Dec 2001 18:59:41 -0500, "CBHVAC"
<st...@carolinabreezehvac.com> wrote:

>Might be...check your air filter...dirty? Replace it.
>If not, call the installing company to have them check it so you can get
>your heat back. The sensors are tripped for a reason, and no..its not owner
>repairable. While you might be able to get it to run, you have not found and
>repaired the condition that caused it.

Yes, my air filter was totally clogged because of lazy cleaning
recently. I hope no permanent damage was done.

[Todd Legere]

I am not filmier with that furnace, If there is no reset button on the
sensor you may have to change it.

"Todd Legere" <toddl...@sympatico.ca> wrote in message
news:9BSQ7.2018$Us5.4...@news20.bellglobal.com...

[profft]

Naw, almost all of the TUE's have been upgraded and the new ones have have
already been setup for flame sense.

"Scott Eslick" <scott...@hotmail.com> wrote in message
news:y5TQ7.105570$Ze5.50...@news1.rdc1.md.home.com...

[profft]

Well it's a bimetal thermo-disc, they sometimes get stuck open, you could
try taping on the black plate a few times with the butt of your screwdriver
or nutdriver. That will sometimes cause it to snap back closed, if it
doesn't call a HVAC company. If possible, talk to the service manager and
see if you can't get a seasoned tech who knows how to reset it, if you get a
younger one you'll be buying a new limit switch just as sure as the sun
rises in the east. I could tell you how but I won't, why take food from my
brothers mouths?

And remember to change your filter every 30 days, everytime you make a
mortgage payment change the filter, the fresh hole in your wallet should
help to remind you for a while but if you tie it to some monthly event it
will remind you long after you've gotten over the sting.

"AJ" <aj00...@tripod.com> wrote in message

news:fi781u0stvmjjcgn0...@4ax.com...

[Hvac Tech]

Well, with a clogged filter, the unit keeps cycling by the limit switch,
which over time will not close again with out a little help. On the XE80,
there will be a little black rectangle object behind the gas valve, and just
below the inducer that is
mounted in the heat exchanger with 2 yellow wires going to it. It needs to
be taken out and tapped hard but not hard enough to break it, reinstalled.
HEAT. Make sure you turn off the power first or other thing will happen,
then every time you pay your morgage, change the filter!!!!

"AJ" <aj00...@tripod.com> wrote in message

news:hk781u07henh5oth5...@4ax.com...

[Jason Dusch]

My sister's furnace had been doing this on and off for months. I replace
the high limit switch, still did it. replaced the flame rollout switch
(wired in series with the high limit), still did it. finally, I found that
the plug assembly (about 9 wires, I think) that plugs into the burner
control was loose! It did not look loose, but when I jiggled it with the
flame lit, it died immediately and I got the four flashes. I unplugged it,
checked it, then plugged in (really tightly this time) and the thing hasn't
died since last january. Check it out!

"AJ" <aj00...@tripod.com> wrote in message

news:8ip71u8cvom26uboh...@4ax.com...

[joh...@gmail.com]

On Monday, December 10, 2001 at 5:06:13 PM UTC-6, Hvac Tech wrote:
> Well, with a clogged filter, the unit keeps cycling by the limit switch,
> which over time will not close again with out a little help. On the XE80,
> there will be a little black rectangle object behind the gas valve, and just
> below the inducer that is
> mounted in the heat exchanger with 2 yellow wires going to it. It needs to
> be taken out and tapped hard but not hard enough to break it, reinstalled.
> HEAT. Make sure you turn off the power first or other thing will happen,
> then every time you pay your morgage, change the filter!!!!
>

I wanted to thank Hvac Tech for the information and help. Followed his advice and my Trane XE80 is back up and running! Thanks again.

[jjbe...@gmail.com]

I just wanted to thank you guys! Especially hvac tech. My fault, i believe, was caused by a power outage last night. I removed the part with the two yellow wires on it behind the gas valve and tapped on it. Screwed it back in and turned the furnace on. Fired right up!! Thanks again

[Stormin Mormon]

Saved your self an expensive service call.

--
.
Christopher A. Young
learn more about Jesus
. www.lds.org
.
.

[allen...@gmail.com]

Thanks guys. The heat is back on. @ profft: as far as taking food away from your brothers, that food is coming from my kids, so think about that for a while.

[PaxPerPoten]

On 4/6/2016 9:18 AM, allen...@gmail.com wrote:
> Thanks guys. The heat is back on. @ profft: as far as taking food away from your brothers, that food is coming from my kids, so think about that for a while.
>

And you do what for a living?

--
It is hardly too strong to say that the Constitution was made to guard
the people against the dangers of good intentions. There are men in all
ages who mean to govern well, but *They mean to govern*. They promise to
be good masters, *but they mean to be masters*. Daniel Webster

[Stormin Mormon]

But, aren't all home owners rich to excess? I
thought only HVAC guys were poor.

[wayne...@gmail.com]

I am having similar problem. I think my limit switch might be bad and am looking for replacement part. But I could not find it any where by googling. Mine is "1NT17L-1759 L120F-30 C340056P11". The closest I can find is "C340056P12 L125F-30". Can this be a good replacement? It seems the temperature for this one is 5 degree higher. Will that cause any problem to other parts of my furnace? I dont know exactly how it works. So, I cannot judge whether the 5 degree will cause any problem.

[Dipak]

Thank you so much for posting this! I just knocked around the thermal protection switch on my XE90, and saved a service call!!!

thank you thank you thank you!

[vossvo...@gmail.com]

16yrs later, thanks to AJ for posting and Hvac Tech for the usable advice--my furnace is also back running thanks to a little knocking of the Thermal Limit Switch. I've got an old Trane (2000?) which I abused with tons of woodshop and construction dust and no filter changes.

Keep in mind there are several pairs of yellow wires! Google a pic of a thermal limit switch to get an idea of what you're looking for.

Mine looked like a dark brown/black plastic plate straight ahead on the sheet metal of the housing, with the two wires attached. Took out 2 screws and pulled out the thingy (metal, rectangle-ish, 3" long, with a small cylinder at the end) tapped it gently with my finger, blew in it, put it back and it didn't work.

So, I undid it a second time, pulled it halfway out and knocked it a bit against the sheet metal back and forth. Put it back et voila! A working furnace. Praise the Lord!

Good luck y'all.

[dar...@gmail.com]

Same here, 16 years later and Hvac Tech saved me. Pulled out the limit switch, gave it a few wacks with the screwdriver, reinstalled it, and HEAT! It was a dirty filter that got me, I purchased a deluxe Hepa filter this fall to help with allergies and just found out you cant go 4 months without changing it! Thanks Hvac Tech.

[rick...@gmail.com]

The inducer blower kicks on, runs for about5 seconds, and then it shuts off, mean while I’m getting 4 blinks that mean thermal protective device open, and nothing else happens, no igniter glowing or nothing, the only thing that runs is the blower motor to the house

[rick...@gmail.com]

Is there anyone out there that can suggest something?

[PaxPerPoten]

On 2/7/2019 6:08 PM, rick...@gmail.com wrote:
> The inducer blower kicks on, runs for about5 seconds, and then it shuts off, mean while I’m getting 4 blinks that mean thermal protective device open, and nothing else happens, no igniter glowing or nothing, the only thing that runs is the blower motor to the house

maybe it is time to push the reset button on the thermal limit switch on
the side of the burner enclosure. Then check to see if burner overflow
is tripping it, Indicating a possible cracked ex-changer or plugged one.
Recommend calling a professional tech.