Propane Detector Activates

[Minipad]

My propane detector activates on occasion and I have narrowed it down to the furnace. The furnace kicks on and then shortly thereafter, the propane detector activates. It only happens occasionally and if I hit the silence button, after a few minutes of blinking red, it turns back to green. The furnace is in fact blowing hot air. If I turn the furnace off, the detector is fine. Any ideas?

[nrgtrakr]

I don't remember the right words to use, but sometimes there is leakage between the fire box side and the hot air plenum. This can go away as the furnace gets up to operating temperature and expands.

When heating is called for, the fire box fan will run briefly to purge the fire box of any possible gas hanging around (the amount of time is a factor of the fire box size and fan cfm). Once purged, the furnace attempts to light. That tiny bit of un-ignited fuel in a leaky fire box is likely what your sniffer doesn't like.

I'd take it to the shop and have it checked. Sometimes a leak can be fixed. Always leaks get worse.

[perryg114]

Sounds like a leak in the combustion chamber. If it leaks propane it might also be leaking CO which will kill you. How much do you use the furnace? There might be a warrantee on the furnace. Unless you use the furnace a lot or use it to keep the pipes from freezing, I can't see why it would be worn out from use. I think the combustion chamber has a longer warrantee than the furnace.

Perry

[nrgtrakr]

Ooops!

Sorry, in my post I was assuming you also have a functioning CO moniter and it smells nothing, is not alarming.

[AWCHIEF]

A few weeks ago I found a small number of ants emerging from under my heater. The gas detector is right next to the heater. I sprayed a little ant killer around and behind the heater. It set off the gas detector. Very sensitive device.

[perryg114]

Propane detectors have been known to go bad and they do have a limited lifetime.


Perry

[Minipad]

I appreciate the replies to my question. I investigated all of the suggestions and did not find the problem. However, after a call to the Atwood tech folks, they suggested that I check the seal of the furnace unit where it is mounted to the trailer on the outside of the skin. Their theory was that some of the exhaust was re-entering the trailer. I opened the access door and found 8 of the 12 sheet metal screws around the seal to be loose by one or more full turns. I tightened all 12 screws and the problem has disappeared.

[dkottum]

It might be good to follow up anything coming loose in the trailer with a rebalance of the running gear, high tire pressure combined with rough roadways, hitch w.d. bars too rigid by design or too high rating for the truck/trailer combo. Inland RV comes to mind who recommends lighter duty w.d. bars for heavier duty trucks, and to always use a tapered bar design.