# Furnace Melted New Floor Vent Louvers



## Scoutr2 (Aug 21, 2006)

We just returned from a cool, Fall weekend camping trip to Comlara Park, near Bloomington, IL (38 degrees Friday night and breezy). When I turned on the furnace for the very first time, it set off the smoke alarm! We had to open all the windows and roof vents to rid the trailer of smoke.









I figured it must be from the newness of the furnace and it had to burn off oil/wax coatings on internal parts. We let the furnace run for about 45 minutes with the windows open until the smoke quit fouling the air. After that, no smoke and it was nice and comfy warm the rest of the weekend.

But on Sunday morning, while sweeping and preparing to leave, my wife tried to close the vent (I just did the floor vent cover mod) that's located in from of the bunks (this one is only about two feet from the furnace outlet). She told me she couldn't close the vent louvers. I assumed she was trying to move it the wrong direction - but alas, I couldn't close it either. After removing it, I could see why - the heat from the furnace had softened and distorted all of the vent cover's plastic below the metal face plate (louvers, outer box, etc.).









The other two vents are about 6 feet and 12 feet away from the furnace, and those vent covers were OK.

I'm not sure if the furnace running full force for 45 minutes caused the melting, or if the air coming out of the furnace should be that HOT! (On my trips to the bathroom in the middle of the night, my bare feet noticed that the floor above the heat duct runs was toasty warm, compared to the surrounding areas.)

Any Ideas? Is this stuff normal (the smoke and high heat)?









Mike, Sherry, Erica, and Arthur (the Collie)


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## CamperAndy (Aug 26, 2004)

The smoke is common for a brand new one and the vents do get hot enough to make you dance if you step on them with bare feet but I would not have thought it would have melted plastic louvers.


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## tdvffjohn (Mar 10, 2005)

What I do not understand is the replacement covers are made for what you used them for. When you get the new one , return the old. That is hot then, would not want to step on with bare feet, new cover or old







The heat running for 45 min should make no difference, I am sure when Moosegut goes winter camping, his runs for at least that when he arrives and sets up









John


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## California Jim (Dec 11, 2003)

Ditto, and replace it with an all aluminum part that wont melt.


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## PDX_Doug (Nov 16, 2004)

Well this is a little troubling! We did the vent mod ourselves, but have not run the furnace yet, so don't know about the melting (ours are also plastic underheath). And I believe I tossed the OEM covers. Hmm...









Happy Trails,
Doug


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## Grunt0311 (Aug 23, 2005)

I replaced them with metal ones from either Home Depot or Lowes, I cant remember which one. They are all metal and shouldnt have to worry about melting.

Bill


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## hatcityhosehauler (Feb 13, 2004)

there is no thermostatic control on the temperature of the air coming from the heat exchanger. It will be as hot as the exhaust of the burner, and the air will cool as it moves forward to the final vent. Remember, the floor vents we purchase at Home Depot and Lowes are made for a home heating system, where the heated air has cooled somewhat before it reaches the plastic of the vent. It's not getting to a vent 2 feet after leaving a heat exchanger, and in many newer homes, is heated by hot water anyway, and is not at as high a temp to start with.

I would replace with an all metal vent, and chaulk it up to experience.

Tim


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## cookie9933 (Feb 26, 2005)

hatcityhosehauler said:


> there is no thermostatic control on the temperature of the air coming from the heat exchanger.
> Tim


Well, not a thermostatic control that you can set, but I bet there is a limit switch that would shut down the burner if things get too hot. This is typically on the heat exchanger or bonnet. We can expect a schematic from Camper Andy to confirm this or shoot me down. I could go out and look at the Suburban furnace book, but that's too much trouble.

Still, I'm surprised that a heater grille would melt. Any other thermoplastic material could also melt that's in contact with the hot air duct close to the furnace...things like electrical wiring or plumbing. Keystone does keep such items away from heat ducts, don't they??

Bill


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## MaeJae (May 12, 2005)

cookie9933 said:


> there is no thermostatic control on the temperature of the air coming from the heat exchanger.
> Tim


Well, not a thermostatic control that you can set, but I bet there is a limit switch that would shut down the burner if things get too hot. This is typically on the heat exchanger or bonnet. We can expect a schematic from Camper Andy to confirm this or shoot me down. I could go out and look at the Suburban furnace book, but that's too much trouble.

Still, I'm surprised that a heater grille would melt. Any other thermoplastic material could also melt that's in contact with the hot air duct close to the furnace...things like electrical wiring or plumbing. Keystone does keep such items away from heat ducts, don't they??

Bill
[/quote]
Maybe it is not moving enough air through the cold air return and it
is getting too hot.
Cookie, maybe your cold air return mod is in store for them???

MaeJae


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## CamperAndy (Aug 26, 2004)

cookie9933 said:


> there is no thermostatic control on the temperature of the air coming from the heat exchanger.
> Tim


Well, not a thermostatic control that you can set, but I bet there is a limit switch that would shut down the burner if things get too hot. This is typically on the heat exchanger or bonnet. We can expect a schematic from Camper Andy to confirm this or shoot me down. I could go out and look at the Suburban furnace book, but that's too much trouble.

Still, I'm surprised that a heater grille would melt. Any other thermoplastic material could also melt that's in contact with the hot air duct close to the furnace...things like electrical wiring or plumbing. Keystone does keep such items away from heat ducts, don't they??

Bill
[/quote]

There is an over temperature switch for the firebox in the control circuit. It will shut off the gas but leave the fan running. I can not find a drawing or an actual control temperature but now I have a bit of a challenge to get it.

I have thought about the problem and I think the furnace inlet needs to be inspected. There is no flow switch in the heating air for the trailer so you need to make sure it is free flowing. Make sure there are no obstructions on the internal air intake. Also take off the last vent in the line and using a small mirror at 45 degrees, held down in the vent, you can see the inside of the entire duct. Make sure it is not collapsed along the path. Any obstruction in the inlet or in the duct can cause a significant difference in the air temperature.


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## jfish21 (Feb 14, 2006)

Rrplaced mine with all metal used it alot this last weekend upper 30's and rainy noooooo problems.


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## Moosegut (Sep 24, 2005)

tdvffjohn said:


> What I do not understand is the replacement covers are made for what you used them for. When you get the new one , return the old. That is hot then, would not want to step on with bare feet, new cover or old
> 
> 
> 
> ...


I sit in the truck and wait until DW gets everything set up and the furnace fired up.









This brings up a question (that maybe I should ask in another forum) - What kind of strain will it put on the furnace to close off one or two of the four vents? I had thought about closing the one nearest the furnace but I've been afraid it would impede the airflow and the furnace would then struggle. Any thoughts from you HVAC guys . . . . or gals?

Scott


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## jfish21 (Feb 14, 2006)

I added the ones that I could close just for that reason
My bunk room would get really hot the living area comfortable and the front bed room and bath would stay cold. I close the bunk room way down living area half way and front bedrrom all the open and I have not had any problems.


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## mountainlady56 (Feb 13, 2006)

When I covered one of mine, last December, with a frying pan (didn't have a closable vent at the time), didn't bother the furnace. 
Darlene


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## hatcityhosehauler (Feb 13, 2004)

CamperAndy said:


> there is no thermostatic control on the temperature of the air coming from the heat exchanger.
> Tim


Well, not a thermostatic control that you can set, but I bet there is a limit switch that would shut down the burner if things get too hot. This is typically on the heat exchanger or bonnet. We can expect a schematic from Camper Andy to confirm this or shoot me down. I could go out and look at the Suburban furnace book, but that's too much trouble.

Still, I'm surprised that a heater grille would melt. Any other thermoplastic material could also melt that's in contact with the hot air duct close to the furnace...things like electrical wiring or plumbing. Keystone does keep such items away from heat ducts, don't they??

Bill
[/quote]

There is an over temperature switch for the firebox in the control circuit. It will shut off the gas but leave the fan running. I can not find a drawing or an actual control temperature but now I have a bit of a challenge to get it.

I have thought about the problem and I think the furnace inlet needs to be inspected. There is no flow switch in the heating air for the trailer so you need to make sure it is free flowing. Make sure there are no obstructions on the internal air intake. Also take off the last vent in the line and using a small mirror at 45 degrees, held down in the vent, you can see the inside of the entire duct. Make sure it is not collapsed along the path. Any obstruction in the inlet or in the duct can cause a significant difference in the air temperature.
[/quote]

I am ashamed for not even thinking of an obstruction in the ductwork, especially since I myself suffered from that fate not two years ago. I will try to find the pictures, and post them for all to see.

Tim


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## mountainlady56 (Feb 13, 2006)

Question: Does anybody else have little round styrofoam beads coming out of their furnace vents? It's like lotto balls rolling around in the vent til some pop out. Everytime I run the furnace, I have to vacuum!!








Darlene


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