LP/CO detector

[Larry C]

Not sure where to put this request, but here goes. Less than 2 years ago, I installed an MTI LP/CO detector in our 34' AS. It failed, after about 9 months, so I bought another one, and it has failed after about a year.

After reading about them, I find they have a normal life of around 5 to 6 years, then need to be replace. I can accept that, however this short life that I've experienced is not acceptable.

I emailed them, and tried to call, left messages, and haven't received an answer. Are they still in business?

Is there any other brand of detector that y'all could recommend that would have a better life?

Thanks

Larry

[Protagonist]

Strictly speaking, combination LP/CO detectors are best for home use, where the gas of choice is CNG, which is lighter than air, and will rise just like carbon monoxide.
Air has a molecular weight of 29.
CNG has a molecular weight of 16, is lighter than air, and will rise.
Propane has a molecular weight of 42, is heavier than air, and will sink to the floor.
Carbon monoxide has a molecular weight of 28, is only very slightly lighter than air, and will rise.
Smoke has a variable molecular weight depending on exactly what's burning, but can be as low as 7, is usually lighter than air, and in general will rise.

As one can see, combination LP/CO detectors should not be used in RVs that use propane, because if placed near the floor, they will not detect CO in time to save you, and if placed near the ceiling will not detect propane in time to save you.

In an RV— or in a home where propane is the gas of choice— the LP detector belongs near the floor where it will be effective, and the combination CO/smoke detector belongs near the ceiling where it will be effective.

[weather command]

so, i started my heater today in the 2006 AS Interstate which runs on propane....it smelled but am not sure it was propane...there was a CO
detector in there ( up high )...i replaced it ( up high )
and now am reading your post that they are worthless in a motor home with propane gas....i let it run with the doors closed for a half hour easy and smell was still there...it was similar to the smell coming out of side of rv...but not as strong....rv has less than 8000 miles on it and previous owner lived in florida and probably never used it? i thought this smell might be burning off type of smell...its hard to believe there is a problem with the heater but now am wondering....wonder how many other people have co's in their rvs?
what to do? how do I figure this out? thanks...

Originally Posted by Protagonist

Strictly speaking, combination LP/CO detectors are best for home use, where the gas of choice is CNG, which is lighter than air, and will rise just like carbon monoxide.
Air has a molecular weight of 29.
CNG has a molecular weight of 16, is lighter than air, and will rise.
Propane has a molecular weight of 42, is heavier than air, and will sink to the floor.
Carbon monoxide has a molecular weight of 28, is only very slightly lighter than air, and will rise.
Smoke has a variable molecular weight depending on exactly what's burning, but can be as low as 7, is usually lighter than air, and in general will rise.

As one can see, combination LP/CO detectors should not be used in RVs that use propane, because if placed near the floor, they will not detect CO in time to save you, and if placed near the ceiling will not detect propane in time to save you.

In an RV— or in a home where propane is the gas of choice— the LP detector belongs near the floor where it will be effective, and the combination CO/smoke detector belongs near the ceiling where it will be effective.

[Protagonist]

Originally Posted by weather command

so, i started my heater today in the 2006 AS Interstate which runs on propane....it smelled but am not sure it was propane...there was a CO
detector in there ( up high )...i replaced it ( up high )
and now am reading your post that they are worthless in a motor home with propane gas....

Please read my previous post carefully.

A CO detector near the ceiling is good. A combination CO/Smoke detector near the ceiling is better. Your Interstate has one or the other of these.

An LPG detector near the floor is good. Your Interstate should have one of these as well.

The one that's NOT good for an RV is a combination CO/LPG detector. These are never factory-installed in an Airstream, but are sometimes mistakenly installed by owners as a replacement for a detector unit that has reached the end of its useful life, or for an older trailer that didn't come with detectors in the first place. Combination CO/LPG detectors are meant for use in homes where the gas appliances are fueled by compressed natural gas, CNG, piped into the home from a utility company.

With regard to the odor you smelled, the only appliance that might give off a propane smell inside the RV under normal conditions is the stove, that has the flame exposed to the interior. The furnace should not smell of propane unless either the furnace or the line feeding propane to the furnace has a leak. The fire on the furnace uses outside air for combustion and vents the exhaust to the outside as well. (same with the water heater).

Dust can collect on the heat exchanger in the furnace when the furnace fan isn't running, and that dust would have to burn off when the furnace is first turned on after a long period of disuse. That is probably what you smelled, as you guessed.

Open a window and turn on the roof vents while running the furnace, and the burned-dust smell should go away. Once the smell goes away, you can close the window and vents, and everything should be copacetic.

[rmkrum]

Unless the smell returns...then get real serious about looking for leaks or a cracked heat exchanger in the furnace.

Had that happen in our home. Old furnace, sorta smelled funny. CO detector never went off. Had trouble keeping the old unit lit reliably one day, called for service. The cracks were clearly visible, and the technician refused to turn the furnace on.

Missed a bullet on that one. Now have new system....