Propane smell when furnace is running - Suburban SF-30F

[SwanInWA]

We're getting a propane type smell whenever we turn on our furnace. No visible obstructions in the intake or exhaust. Did the soap check for leaking, switched to a fuller tank, but we're not having any luck isolating the issue. The odor is only present when we run the furnace. It's definitely coming from the ducting. Any suggestions? The trailer is about a year old. It's a Suburban SF-30F furnace.

[aruba5er]

I would gamble you have a bad heat exchanger: look real hard at every part of it. Years ago I bought a smoke candle. You light it and it makes a ton of non toxic smoke. Then you could see if the heat exchanger is cracked. Might be hard to do on such a small unit. Or force air into the exhaust and see is you have and movement out of the heat tubes. or is the unit pipes sealed well when it's installed. so not getting any exhaust back into the rv?

[John_Joey]

You could have a cracked heat exchanger, something I wouldn't play around with. Nothing worst then waking up dead. On that topic I would buy a carbon monoxide detector and plug it in.

Since you got the unit out you can bench test it pretty easy. All you need is a 12 volt battery and a propane line. Take it outside and hook it up and see if you can spot what the problem is. Go to YouTube to see how to bench test it.

[ken56]

At only 14 months old that furnace should be fine but you never know. Do you have any idea how many times that furnace has been used? It takes quite a while to get the oils to burn off a new furnace heat exchanger. It will produce an acrid offensive smell that will burn the eyes and nose and be most unpleasant. All I can suggest is run your furnace as much as you can when you aren't in it and see if it clears up. Ours took about 2 tanks of propane to clear it up. I am able to keep my unit at home so I ran it in the winter when we were not using it. It did finally go away.

[TakingThe5th]

SwanInWA wrote:
The trailer is 14 months old, I was just generalizing. 🙂 We're the second owner. Maybe we're wrong, maybe it is exhaust -- now I'm starting to second guess. It's pretty strong and it only happens when we run the heater.

The heater is now sitting on our dining room table. This is how much it's bugging us! Any advice on what we should look at? I have a Symbion Portable Propane Natural Gas Leak Detector in my Amazon cart ($23). Anyone ever used one of those?

When I had a problem with my SF-30 I discovered that most HVAC guys I spoke with knew these RV furnaces. My point is that you might make some calls and see if you can find someone who can check out your unit.

Option 2 might be to contact a portable Rv repair tech, explain the problem and invite him to re-install the unit.

Option 3 is to spend some time with the unit on your "workbench". Clean the unit, shake out any heavy baked bug stuff from the exchanger and look for holes See if you can rig up a pressure test of the heat exchanger. Maybe use a vacuum cleaner (blowing and/or suction) against the exhaust or intake while blocking the other to see if you can discover a leak. Be mindful of the sail switch and other components so you don't damage them.

Good luck

[time2roll]

Get a mirror and look down the ducting that all is clear.
Does the burner cycle during the heating process?
Do you have a CO detector tested with new batteries?

I have a sniffer leak detector and they do work well in still environments. Your issue is while running so the leak detection could prove difficult.

Check on the furnace warranty. and +1 to have a professional confirm the odor.

[ksg5000]

Take your rig into a commercial propane outfit - ask for refill of the tank and explain that you occasionally smell propane ... chances are they will spend a few minutes and find/fix the problem at no cost.

[SwanInWA]

The trailer is 14 months old, I was just generalizing. 🙂 We're the second owner. Maybe we're wrong, maybe it is exhaust -- now I'm starting to second guess. It's pretty strong and it only happens when we run the heater.

The heater is now sitting on our dining room table. This is how much it's bugging us! Any advice on what we should look at? I have a Symbion Portable Propane Natural Gas Leak Detector in my Amazon cart ($23). Anyone ever used one of those?

[ford_truck_guy]

You said the trailer is only ABOUT a year old. . . Find out how old, and IF your the original owner you may be able to get it replaced under warranty if it needs to be...

Call the dealer, or manufacturer.

Don't mess with possible propane leak, or smell

[Dave_H_M]

Man, you need to get someone in there with some detection equipment if you are sure it is propane.

i could understand exhaust, but propane i don't know.

[SwanInWA]

The heater works -- but we've been running it for days and the smell is still there. I suppose it could be exhaust, but we've been RVing for 25 years and we're pretty familiar with the smell of propane. It does not set off the gas detector, but the smell in the RV is strong enough to be annoying. We're leaning toward the heater itself as we're almost out of ideas. However, I sure as heck don't want to spend $500+ on a heater unless I'm SURE. Thanks for the suggestions. How can we tell if there is a hole in the heat exchanger?

[TakingThe5th]

I hope you don't have a hole in your heat exchanger.

[Joe417]

If the furnace is working and you've checked for leaks it may be contaminates burning off the heat exchanger. Our furnace smell very strong for about an hour when first lit for the season. It is very strong, take your breath away strong, so we open the window and turn a vent on. Usually has a slight smell for a few more cycles and then usually gone by the next day.

Verify the smell is propane, go out to the tank, disconnect the hose and smell. If the smell is the same, you'll need to keep looking for a leak.

Does it set off your gas detector??

You might want to verify no rotten rodents in the ducting also.

[2oldman]

Mine does the same thing with the WH running. I think you're smelling the exhaust.