2529RG Propane Furnace Issue

[No1Hunter]

We just returned from our third outing with our 2022 2529RG TT, and it seems we have a furnace issue. We had shore power, but rather than use our little electric heater, we decided to use the propane heater.

The propane heater starts up and blows warm air, but this is the issue. The fan comes on, in about 15 to 30 seconds later, the furnace fires up and runs for about a minute or two and then turns off with the fan running for another 15 to 30 seconds, and then it turns off. In about 15 minute, it does this again. We had the thermostat set for 69 degrees, and the temperature inside the TT never got above 60 - 62 degrees. It seems to me the furnace should run until the air temperature reaches the temp on the thermostat.

Any ideas? My dealer is over a 100 miles away. So, it's a little inconvenient to take it to them at this time.

[Morich]

One of the bigger problems with trailers is that we get far less info n how to fix them!
But there is a workaround if we do a bit deeper looking. Finding the correct model name and number for the furnace from the info bag or looking at the furnace for a nameplate, so that we know what to look for, can let us go online for troubleshooting flow charts for that specific furnace.

As just a oure random idea (but quick!) one might try running the furnace with the outside door open as I have seen some posts that complain about a lack of air to keep the fire burning when the outside door is closed.
Maybe try the "shotgun" troubleshooting to test that idea?
That one may not be in the flow charts!

[creativepart]

I'd guess the suggestion you'll hear the most is to check the "Sail Switch" as that's a common fail point. But your TT is so new that doesn't sound like an option.

More questions - does the furnace fire up? Do you hear it light. You should hear click, click, click and Whoosh. Do you smell propane? While it's trying to light, go outside and smell at the exhaust port and see if you smell propane.

An obvious thing to check is to insure you have Propane, have it turned on and can run the stove and RV fridge (if you have one) on propane.

The furnace goes through stages.

1. Fan Starts
2. Gas valve opens
3. Electric igniters make 3 or 4 attempts to light the gas burners
4. The igniter is also the device that senses the presence of flame, so it checks for flame
5. If no flame is sensed it shuts the gas valve and runs the fan for a while to dissipate any gas fumes
6. Then turns off.

I had a similar problem on my 5-year old motorhome and it turned out to be the circuit board. Other options for this issue are the gas valve, the igniter, and the flame sensor. As well as the "sail switch" mentioned above.

It also can be as simple as a bug nest in the air intact that is blocking air flow to the furnace.

Good luck figuring out which it is.

PS. Besides taking it to the selling dealer you can take it to a Suburban Heater authorized repair center - which is likely to be an other RV dealer. Also, if you call Winnebago you may be able to get them to OK a repair from a local shop or even a mobile RV Tech that will come to you.

PPS. I'm assuming you have a Suburban brand furnace as that's what WBGO has used for decades - but who knows what they are installing now a days. It could even but a German Truma heater for all I know.

[creativepart]

Originally Posted by Morich

As just a oure random idea (but quick!) one might try running the furnace with the outside door open as I have seen some posts that complain about a lack of air to keep the fire burning when the outside door is closed.

Richard, the furnace doesn't have an outside door. You're thinking of the Water Heater - that's the device with an outside door that some folks have found opening helps with breathing.

The furnace has one or two small exhaust ports on the outside and bugs, etc can build a nest and block those.

[No1Hunter]

does the furnace fire up? Do you hear it light. You should hear click, click, click and Whoosh.

Yup and it blows warm air out. Reading the manual - Troubleshooting section, it says:

1. - Check to make sure vents are not obstructed. Did that. In fact, I adjusted the vent in the dinette as it was installed only partially centered over the hole from the distribution duct. It still doesn't produce much air flow but better than what it was doing before. I also partially covered the duct on the passthough hoping to push more warm air into the TT.

2. - It said to verify the air return is not obstructed. Hum, not sure where that is as I haven't actually found one. There is a vent in the floor under the pantry, but warm air comes out of it when the heater is on, and I read (somewhere) it is a heat vent.

FYI - It is a Dometic Heater

[Morich]

Originally Posted by No1Hunter

Yup and it blows warm air out. Reading the manual - Troubleshooting section, it says:

1. - Check to make sure vents are not obstructed. Did that. In fact, I adjusted the vent in the dinette as it was installed only partially centered over the hole from the distribution duct. It still doesn't produce much air flow but better than what it was doing before. I also partially covered the duct on the passthough hoping to push more warm air into the TT.

2. - It said to verify the air return is not obstructed. Hum, not sure where that is as I haven't actually found one. There is a vent in the floor under the pantry, but warm air comes out of it when the heater is on, and I read (somewhere) it is a heat vent.

FYI - It is a Dometic Heater

Getting down to the best info is what I promote as I totally missed on my thinking as I was thinking of the water heater problem, not the furnace.

Getting the right info is often critical as there are frequent small changes made on lots of things on our RV. So if one guy has an older model and there has been some change made on your model, the info may be totally out.

And those small points are often critical like looking for insect nests as we probably have moved past that.
The fan comes on first after we set the thermostat, that air movement goes past the sail switch and only if the sail switch closes the circuit, then the gas valve is opened. The idea here is that the sail switch has to sense that there is good air flow thorugh the furnace as away to avoid pumping a bunch of gas into a space where the air lets itbuild up and thensuddenly explode. Not enough air moving, no gas! So if you have something hanging the sail switch, the gas valve should never open and the burner never lights.

I'm assuming you mean you are getting heated air, not just the ambient air on a 100 degree day? You could fry an egg with my ambient air right now!

Since you mentioned you get heat, we can move several steps down the troubleshooting charts as the thermostat is working, the furnace is getting that message,the blower comes on and the sail switch closes to let gas in. The ignitor is working to set the gas on fire, too.

That does leave several things, including how the air is moved from the furnace to the room, so the furnace doesn't get so hot it might catch surrounding wood on fire. That's where the owners manual tells to check the vents into and out of the room but since it takes a pretty hot spot to shut the furnace down due to overheating and you did not mention anything like smell, etc. to think of overheating (usually takes a while to get that hot?) I tend to think of it as a different sort of problem like a small button thermostat on the furnace shutting it down way too soon, a board not working right, etc.

This is a link to some of the current RV furnaces dometic sells to show how many different choices you have when you start to think about a furnace that has been put in so many RV:
https://www.dometic.com/en-us/outdoo...ns/rv-furnaces

And each one is prone to having it's own special little points to follow when we want to fix one, so getting the right model and the right manual is where I like to start as it helps to avoid going up those blind alleys!

Note: The return air is often only a grate at the front of the furnace and might be overlooked as being part of the furnace operation.

[No1Hunter]

I'm assuming you mean you are getting heated air, not just the ambient air on a 100 degree day? You could fry an egg with my ambient air right now!

It was 48 degrees outside this morning and 62 degrees in the TT. Yes, the air coming out of the vents was warm but not air fryer hot!

Note: The return air is often only a grate at the front of the furnace and might be overlooked as being part of the furnace operation.

The heater is located in the rear driver side corner of the TT next to the water heater and under the kitchen sink. It is not exposed to the interior of the TT. Of course, the owner's manual doesn't't explain a thing.

[Morich]

Okay, better idea of how it fits. IF you can pull some drawers or open some cabinets to see the ductwork better, it may be worth the time to try to spot if some of them are pulled loose or mashed someway to keep air from flowing but that seems not right for now as the furnace has to get pretty hot to shut down for safety and then it likely would need longer to cool off than you mention.

Something with the controls like the thermostat or some of the safety button thermostats on the furnace itself, possibly a bad board seem more likely??? Is this a furnace that has a panel on the outside that you can pull off to look at the wiring and such?? Look for loose wires,maybe?

[No1Hunter]

Richard,

Thanks for the responses. I will dig into tomorrow and see what there is to see. There is a thermostat that controls the heater and the air conditioner.

Bob

[Sentry]

My furnace is propane only. Do they have furnaces that do both?
My water heater does both.

[No1Hunter]

Originally Posted by Sentry

My furnace is propane only. Do they have furnaces that do both?
My water heater does both.

No, they are separate.

[Sentry]

If you set the heat to 69, what did you set the A/c to?
Video we watched said set A/C to 76, and heat separately.
I’d imagine, if they are set to close it might not work well. It may be a thermostat problem. Just thinking

[Sentry]

https://youtu.be/HhT5v0i2vVo

[No1Hunter]

Originally Posted by Sentry

If you set the heat to 69, what did you set the A/c to?
Video we watched said set A/C to 76, and heat separately.
I’d imagine, if they are set to close it might not work well. It may be a thermostat problem. Just thinking

That is an interesting subject as last week, when I was fixing the vent under the dinette, I had the TT attached to a 20amp circuit at home and both the heater and air came on. However, that wasn't the issue this time.

My thermostat does have a separate heat and separate air setting.

[No1Hunter]

Originally Posted by Sentry

https://youtu.be/HhT5v0i2vVo

Good info as that is the thermostat we have.

[Sentry]

https://youtu.be/XgGVfyCiln4

[Sentry]

https://youtu.be/o7LDLDZ3kYk

[Sentry]

Hope this help

[No1Hunter]

Well, after watching your videos and a couple others, i went out and found the air return. It is inside the kitchen cabinet, and it appears the piece of paneling covering the wiring, hot water tank hoses, etc was pushed up tight. This may have been obstruction to the air flow. I pulled it off and will test the unit in the morning.

[No1Hunter]

I’m also going to vacuum up all the sawdust and other crap that was left behind under there and under the heater!!!