Jet-sounding neighbour furnace

I, too, suspect an obstruction in the furnace burner tube, possibly mud dauber nests, maybe spider webs, or even just a pile of dead stink bugs. This is also likely the cause of the furnace coming on for just a minute before shutting off, only to come on again for just a minute a brief time later.

You would be doing him a favor to tell him you think there is a problem. If that burner tube is obstructed, it is also quite likely making carbon monoxide in prodigious amounts, which could kill him (or you). At the very least, it will be wasting a lot of propane by a burn cycle like that.

Last spring, the first time I fired up my TT's water heater, it sounded like a jet engine. It had always had a faint roar, but this was impressively loud. I went outside to investigate, and that's when I saw the big black carbon plume going up the side of the trailer. I shut the water heater off immediately and quickly determined that I had a burner tube full of dead stink bugs. Took all of a minute to clear them out, whence the water heater returned to normal operation. Took some serious scrubbing to clean the soot off the side of the trailer.

Took the picture from our window via the screen, so excuse the quality.
The noisy furnace is on right hand side, when I see WH on left margin.
I think the exchanger overheat theory is right here, as I can hear the noise going for few minutes, shutting down and then a minute later coming again for a minute.

Kayteg1,

Wow, that must a loud furnace if you can hear it with your windows closed! What kind of coach is it? Would it have an Aqua Hot system? Our previous AH system just made a humming noise. I kept it in tip-top condition with very little fumes and it ran smoothly.

Our current system is called an Espar that is similar to the AH. Ours is an 83,000 btu unit and makes a little louder sound but would never bother the neighbors (in my opinion). But, we are using electric like you. It's getting down in the low 40's/ upper 30's here in Vegas.

I think I would mention the noise to your neighbor as they might not be aware there could be a problem.

Good luck,
MM.

Here is Florida, we get a lot of mud dauber nests on any opening on the RV. We are constantly cleaning them out. I did notice one time that the noise from our furnace was louder than normal and it was a mud dauber nest that was disrupting the air flow and created more noise.
I'm not sure how to approach the neighbor about this other than trying the direct approach and telling him you think there may be something wrong with his furnace.

Furnace, although a DC & propane hog, should NOT be that noisy.

Water heater when on propane IS LOUD because burner is more open then furnace burner.

A friendly opening conversation with neighbor can go a long way.

"Howdy, this cool weather sure is something. I noticed your furnace is cycling on/off frequently and seems kinda loud.Is it keeping your rig warm?"

Response will clue you in on whether or not further discussion can continue.


His furnace is most likely 'limiting'-------cycling on/off due to high temp limit switch opening due to heat exchanger getting too hot. Then closing and refiring furnace when heat exchanger cools down----t-stat set point not satisfied.
Obstruction in furnace discharge and/or return air. That would also cause furnace to be loud.

Majority of high end DP do not have furnaces. What you're hearing is his Aqua Hot system, which is diesel fired, and provides both heat and hot water for the Coach. They are loud and tend to put out a lot of fumes. Newer Coaches are running exhaust out the rear to minimize these issues. I always try to minimize my use and turn it off when done. They do have the electric element which provides basic heat and hot water.

You sure it's not his water heater? I can't imagine a furnace running every 5 minutes, shutting down, then getting cold enough to cycle again...

I'd just bring it up in conversation. If it comes on that often it'd probably come on when you're talking to them :)

"wow, what is that, your water heater or furnace?"