Dometic water heater only runs on propane with outer cover open

ZoraK9 · 04-03-2022, 02:05 PM

A quick search showed a few similar reports but not anything definitive on this, so I thought I'd ask directly.

Yesterday I finally got a chance to dewinterize and test everything on our month-old 2108DS Micro Minnie trailer. Other than a small leak at the P-trap under the kitchen sink (quickly fixed with a bit of tightening) I only found one real issue:

On propane, the water heater shuts off after a minute or so, unless I leave the outer cover wide open.

Yesterday, I stood outside the unit while the water heater was running, and I could hear the flame starting to fail, and it would immediately blaze up again as soon as I opened the door. But if I didn't catch it in time, it would go out, try to restart a few times, and then give up.

Found a couple videos online that suggested (after letting everything fully cool down, of course!) blowing compressed air into the gas tube, adjusting the distance on the flame sensor elements, and a couple other things. I tried all of these, with no joy.

Wondering if anyone else has been through this, and has ideas on potential causes/fixes. A problem with the emergency cut off? Bad sensor/board? Just the flame being oxygen starved?

The trailer is under warranty, and I'm planning to schedule a service repair when the dealer opens on Monday, but since we have a longish trip starting later in the week I'm wondering if there's an easy fix I could try on my own.

Also, is there any downside for now to just opening the outer cover anytime I want to heat up some water?

mark96ss · 04-25-2022, 09:13 AM

Mine has the same issue. The unit is starving for air. If you take it in to the dealer, all they will likely do is remove some of the sealant around where the door seats and insert a small prop at the top of the door panel. That is Winnebago's "fix". Some owners have installed a screened vent in the door. I bought a 3" louvered vent with screen form Amazon. That install is one of the next on my long list.

Ray,IN · 05-03-2022, 08:27 AM

There are Suburban and Atwood water heaters, which one do you have? My Atwood used to do that until I adjusted the air adjustment on the burner tube so it had too much air with the doors open, when the inner and outer doors are closed, now it burns so quiet you must go stand by it to hear it burning..

BTW, nice looking paint.

ZoraK9 · 05-03-2022, 08:36 AM

It's a Dometic. This one:

https://www.dometic.com/en-ca/outdoo...-6gea-_-219438

I've attached a picture of it in my trailer.

I have a service appointment on Thursday at the dealer in Albuquerque to look at that and a leak under the kitchen sink. Otherwise, this trailer has been a joy to travel in--we just got back from a three week trip between NM and the SF Bay Area.

Morich · 05-03-2022, 08:59 AM

I think of this as an almost "given" looking at what the picture shows!
Most of us do have some type of bug that wants to build a nest where it is warm and dry. Things like wasps, mud daubers, and spiders are living with most of us, so when they find a nice place like an RV setting where nobody uses it for a while, they move in.

Some of their favorite spots are the vents on our water heater and furnace!
So I see no screens over the vents and the builders do not add them and that sets us up for failure!

If air has to go in the vent, down to the tube where the fire burns and then up and out the upper exhaust and there is a big wad of some form of nest in the tube, the airflow is restricted! You do have the odd situation in that it does burn with the door open but has anybody checked for stuff in the tube?

No guarantee on that guess but it does happen often and WILL almost certainly happen if screens are not put on vents. I make it step one on new RV to put screens on the furnace, water heater, and frig.

Got any bugs where you live?

ZoraK9 · 05-03-2022, 09:01 AM

Quote:

Originally Posted by Ray,IN

BTW, nice looking paint.

Ha! I was scratching my head trying to figure out where I'd posted a photo of the paint job on my trailer, before I realized you were talking about my profile photo.

That's Molly, my 25-year-old paint horse and the love of my life (don't tell my wife!). I'll pass along your compliment, thanks!

ZoraK9 · 05-03-2022, 09:07 AM

Quote:

Originally Posted by Morich

I see no screens over the vents and the builders do not add them and that sets us up for failure!

I actually do have one of those Camco rectangular screens over the vent area--as well as the fridge and furnace vents on the other side. I had to take it off for the photo in order to swing the door down.

But you raise a good point. I did a visual inspection of the burn tube and blew some compressed air in there, and no creepy-crawlies scuttled out. If there's something larger, like one of our local tarantulas, hiding in there, I'm fine letting the repair crew at our dealer discover it!

Morich · 05-03-2022, 11:05 AM

Quote:

Originally Posted by ZoraK9

I actually do have one of those Camco rectangular screens over the vent area--as well as the fridge and furnace vents on the other side. I had to take it off for the photo in order to swing the door down.

But you raise a good point. I did a visual inspection of the burn tube and blew some compressed air in there, and no creepy-crawlies scuttled out. If there's something larger, like one of our local tarantulas, hiding in there, I'm fine letting the repair crew at our dealer discover it!

Good enough! I did jump to the wrong idea on screens then?

One of the things we get is the paper wasp building a nest and as they get bigger the problem gets bigger until we notice something.
The newer high efficenty furnaces that use simple PVC pipe as exhaust areone where it often runs just horizontal out the wall as it has a fan blowing, but over the summers when folks are not using the furnace the wasps get in that horizontal pipeand build the nest to fit the curve of the pipe and then when winter comes the furnace won't run because the combustion air is not enough to close the switch!

If you want to be obsessive and try one more thing, I thin wire like a clothes hanger might snag something hanging on the top of the pipe?

Sorry! I do almost anything to avoid taking it in to the shop!

Ray,IN · 05-07-2022, 03:16 AM

Zorka9, only use those bug screens during storage. They reduce air flow enough to affect proper combustion. In you owners manual you'll find a statement that says the warranty is void if these bug screens are used while the water heater or furnace is being used.

I used to raise and train quarter horses. Yes, one can easily get soundly attached to a good horse. I had a 22 yr old Morgan for trail riding that was_well you know.

NV_Camper · 05-31-2023, 02:05 PM

Quote:

Originally Posted by mark96ss

Mine has the same issue. The unit is starving for air. If you take it in to the dealer, all they will likely do is remove some of the sealant around where the door seats and insert a small prop at the top of the door panel. That is Winnebago's "fix". Some owners have installed a screened vent in the door. I bought a 3" louvered vent with screen form Amazon. That install is one of the next on my long list.

Nice to find someone that actually has an official fix! I guess I'll just do this too now since there isn't anything better.

NV_Camper · 05-31-2023, 02:09 PM

Quote:

Originally Posted by ZoraK9

I actually do have one of those Camco rectangular screens over the vent area--as well as the fridge and furnace vents on the other side. I had to take it off for the photo in order to swing the door down.

But you raise a good point. I did a visual inspection of the burn tube and blew some compressed air in there, and no creepy-crawlies scuttled out. If there's something larger, like one of our local tarantulas, hiding in there, I'm fine letting the repair crew at our dealer discover it!

Did you find out anything at the dealer? Mine has looked at it several times and basically nothing is done.