Dust mitigation through Suburban Furnace

[Clarkboulder]

Anyone with any idea how to prevent copious dust from entering through the furnace vent? Is it coming from the outside exhaust port or something else? I considered covering the vent but that’s a terrible temp fix until I use the furnace next. Yuck!

This is annoying.

[86Scotty]

Wow. I have never seen this. That's some serious dust!

Pretty much has to be from your intake. I would remove the wasp proof cover you have on it and replace with something solid. You might be able to hack something up to try first like wrapping it in aluminum foil and replacing. Of course you need to be very careful not to start your furnace without removing. Maybe take the fuse out of that slot in your house fuse panel just to be sure.

[larrie]

We get dust through the back doors, not through the furnace. That’s weird.

[Clarkboulder]

Of course that was from driving collectively for about 4 hours on dirt roads over the weekend but still. I also had to close off some holes in the fiberglass house battery compartment as well as that was another place for entry but this clearly is dumping out of the furnace vent. I looked into that exhaust vent abs it didn’t look as dusty as the furnace insides. Weird

[1der]

That dust presence is potentially not good. The Suburban heater is supposed to be a "closed" system. Combustion intake air into the flame chamber and the combusted air is expelled to the outside. The combustion chamber (and therefore combustion intake and exhaust) is not at all directly connected to the cabin. Cabin air is drawn in around the outside of the combustion chamber in a heat exchange configuration with the hot cabin air blown back into the cabin.

Dust present inside the heater should not happen w this sealed system unless there is a gasket failure or cracked part in the combustion chamber /intake/exhaust.

Do you have the manual w the parts diagram?

[simplesez]

It isn't a completely sealed system. The back of the suburban by the van wall is completely open. Dust can get in there and get through to the front where the grate is. Look at this image. I've pulled the suburban out and it is not attached to the wall so there is no seal on that side. There could be a gap.

It could have nothing to do with the heater and just be where dust collects either from the back door or from the wheel well. You have linoleum floors so dust moves around easily.

It isnt coming in from the exhaust if that is what someone is thinking. From that direction it would go into the chamber and not the van interior as 1der mentioned.

[Clarkboulder]

This is all good info. thanks for helping me brainstorm it. What Simplesez says could be accurate in this case. I found that the house battery fiberglass compartment was full of holes....its possible that the dust is entering there and somewhat being pushed into the furnace housing and out the vent. Yesterday I sealed off the battery compartment (but gave it the appropriate vent on top for the battery) and rearranged the second series battery. When doing this, I noticed that the perpendicular cabinet wall housing a closet and below it the furnace that connects to the SMB vertical van wall was not perfectly tight and had a gap that flexed easily. It should be easier to see if the bat. compartment work has any effect on the dust from the Furnace. (I know it will for the back of the van as dust was coming in from the bat. compartment as well.) If it doesn't fix the furnace dust then its coming from somewhere else. I agree it does not seem to be coming from the exterior exhaust ports. More thoughts and mitigation ideas welcome.

[doublevan2]

I would only be "guessing" here - but what year is the van/system ? Could it be a cracked combustion chamber - water/condensation collection and when dust is dried out after system sets for awhile - that rust (?) dust is blown out thru the ducting ? Are you smelling any fumes from propane/fuel source - acrid smelling ? Our older house furnace fueled by Nat Gas - had a cracked combustion chamber and acrid smell alerted us to the problem.

[Clarkboulder]

Its a 96' I think this is dirt dust from off road driving. Furnace is propane. I haven't used the furnace much but when I do, its at night and it doesn't put off any smells. Heat output seems marginal but I don't have anything to compare to. I have been smelling occasional gasoline in the cabin when parked engine off and when coasting off the accelerator at 15-25mph. I am still searching for that source. could be burning rich or a leak somewhere but i've checked many things and can't ID it...for another post :-) one thing at a time.

[1der]

I would look at what simplesez posted.

The cabin air intake sucking in the dust from the battery box/back doors and blowing it out the front where it is collecting on the floor. The furnace cavity likely has quite a bit of dust in it as do the fan vanes.