Eye Burning Smell from Furnance

[Greengas]

On our way home from our last rally, we/I accidentally had the heater turned on while we were on the road. I have closable vents and they were all closed. When we stopped for the night, the smell inside the rig was terrible. Our eyes were burning. We slept with the windows open and did not use the heater again.

Turned it on last night and that same smell/burning odor was there. I opened up the basement and found that one of the hoses disconnected from the unit so I fixed that but the smell was still there. In fact, it actually triggered the smoke alarm (I did not see any smoke and nothing was cooking).

My guess is the heater hose disconnected due the force of air and no where for the air to go. My question is, is it possible that something burned in the furnace due to the high heat build up and that is what we are smelling?

As always, thanks in advance for the help, guidance, assistance.

 

[TravelTiger]

On our way home from our last rally, we/I accidentally had the heater turned on while we were on the road. I have closable vents and they were all closed. When we stopped for the night, the smell inside the rig was terrible. Our eyes were burning. We slept with the windows open and did not use the heater again.

Turned it on last night and that same smell/burning odor was there. I opened up the basement and found that one of the hoses disconnected from the unit so I fixed that but the smell was still there. In fact, it actually triggered the smoke alarm (I did not see any smoke and nothing was cooking).

My guess is the heater hose disconnected due the force of air and no where for the air to go. My question is, is it possible that something burned in the furnace due to the high heat build up and that is what we are smelling?

As always, thanks in advance for the help, guidance, assistance.

Any more description of the type of smell... is it an electrical, plastic, wood, or something else?


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[danemayer]

Ronn,

With vents closed, the combustion chamber will overheat and should cycle on and off as the high-limit switch cuts power to the gas valve to allow temp to drop. But if the hose got blown off the plenum, all of the hot air would leave the combustion chamber and instead, heat things up near the furnace. I'd check water lines, hanger straps, rubber flooring for evidence of heat damage.

 

[sengli]

We have this sort of smell, when ever we havent used the furnace for some time. As we are anytime campers, our furnace doesnt get used a lot. It usually fades after the first 10 minutes or so. We usually have the windows open to vent this stink.... till the smell gradually goes away. I think its the combustion chamber burning off, after it not being used.

 

[Desertsky]

Any resolution to this one?

An eye-burning odor would indicate some kind of plastic or other synthetic burning. Since a hose came off, the furnace was short-cycling the hot air inside the heater. Check all the wiring and fittings carefully as you probably had really hot air circulating inside it. If you are capable, remove the heater and take off any covers and check it out thoroughly. Otherwise, I suggest having it done by a qualified tech. A gas heater is not something you want to fail inside your unit.

 

[Greengas]

Solved: Eye Burning Smell from Furnance

I asked the RV tech who was installing my residential fridge to look into the heater smell problem. He found the plastic squirrel cage was broken and pieces of it were in the heater and melting when the heater was on. He removed all the pieces and installed a higher quality metal squirrel cage.

Problem solved.

 

[jerryjay11]

Ronn,

With vents closed, the combustion chamber will overheat and should cycle on and off as the high-limit switch cuts power to the gas valve to allow temp to drop. But if the hose got blown off the plenum, all of the hot air would leave the combustion chamber and instead, heat things up near the furnace. I'd check water lines, hanger straps, rubber flooring for evidence of heat damage.

I'm sure you meant the "heat exchanger" not "combustion chamber." My goodness they wouldn't be here to write about it if the combustion air entered the camper.

 

[danemayer]

I'm sure you meant the "heat exchanger" not "combustion chamber." My goodness they wouldn't be here to write about it if the combustion air entered the camper.

When I had my furnace apart, there was a plenum to which the ducts are attached. The plenum is empty - nothing inside. The plenum is attached to the combustion chamber which has a burner inside. On the other side of the combustion chamber is the blower, which forces air through the combustion chamber where it is heated by flame and then the air goes into the plenum and from there to the ducts.

 

[jerryjay11]

When I had my furnace apart, there was a plenum to which the ducts are attached. The plenum is empty - nothing inside. The plenum is attached to the combustion chamber which has a burner inside. On the other side of the combustion chamber is the blower, which forces air through the combustion chamber where it is heated by flame and then the air goes into the plenum and from there to the ducts.

Believe me you do not get air from the combustion chamber. The heated air comes from the plenum which is heated by the combustion chamber (heat exchanger). Combustion air is exhausted out the discharge (like chimney in your house).

Combustion chamber is where the fire occurs. The heated gases pass through the heat exchanger (the tubing that wraps back and forth) then out the discharge to the outside of the camper. The plenum is the attach point for the ducting to be routed to the inside of the camper. Heated air from the plenum is forced into the living space by the blower. If combustion air were to enter inside the living space you wouldn't live long as the carbon monoxide would do you in. Never the two should meet.


I am a retired HVAC technician with over 30 years experience.