draft coming in through furnace intake register

[livefreeordie]

My alpine 3500 RE has the intake for the furnace through a slotted wood grill in the stairs up to bedroom. When not using furnace, there is a tendancy for cold air to flow into living area from underbelly. Ive considered removing wooden cover and installing strips of heavy plastic, much like in meat lockers, that prevent flow out but allow flow in. Anybody deal with this problem?

[Campy]

That would only be a problem if you use the furnace. That's the return air duct for the furnace so closing it off will not allow the furnace to "pull in" the cold air from the floor. The flaps might do the trick but their small size could cause issues.

[rclark]

We had the same problem and just put a rug of the whole stairway. We use electric fireplace except when dry camping and then we remove the rug since as stated this is the cold air return for the gas furnace.

[Alpine3100RL2115]

Idea! Put good air filter behind that grill and use the rest of a big house filter in the outlets. Cut to fit. Change monthly if needed. Run the fan to clean the air, better sleep.
Frank


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[JRTJH]

The Atwood Furnace Service Manual is pretty clear about filters in the return air passage:

"#4 - RETURN AIR
The return air passage should meet the minimum square
inches as specified for the particular model of furnace in the
installation instructions. This air passage should also be
clean and clear of obstructions. Do not put air filters in this
passage way. Also make sure that combustibles are not
stored in the furnace compartment."

The RV Doctor series on RV maintenance states this about the furnace return air: "Some coach owners mistakenly install a filter in this vent space; a definite no-no. Unlike a home heating appliance, there should not be a filter installed anywhere in the path of the return air."

http://www.rvdoctor.com/2002/02/rv-heating-system-maintenance.html

For those who are so inclined. The RV Doctor website is filled with excellent information about the wide range of RV care and maintenance and does a very good job of explaining how most "things RV" actually work. Knowing the "how it works" certainly helps when it comes to "how do I fix" questions. Find it here: http://www.rvdoctor.com/

[PARAPTOR]

Having just closed up my basement area under the second floor, Those slots you see in the steps are merely another source of air to this entire basement area. The furnace in my Raptor is around 4 -5 feet away from the bottom step. The actual intake on the furnace is around a 5x3" opening to the surrounding basement area. This same area is open to the underbelly where your tanks are.

[Alpine3100RL2115]

Ok is replacing the cleanable eyeball foam with Good 3M filter ok? Then run the fan? Less dusting better sleep!
Frank


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[Festus2]

Ok is replacing the cleanable eyeball foam with Good 3M filter ok? Then run the fan? Less dusting better sleep!
Frank


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Alpine3100 -
I would suggest that you read the cautions/warnings in your furnace's owner's manual and go to the RVDoctor's link and read for yourself what it says about placing filters in furnace intake/outlet system.

Again, as JRTJH pointed out in his post above, both tell you NOT to use filters. It doesn't say that you can use Furnace Filter Brand X or Y or that a 3M filter is okay. You should assume that any type of filter, regardless of brand, is not to be used.

As far as dust is concerned, it is recommended that you access the furnace fan and remove all dust and dirt from it as well as vacuuming around the furnace. Just make sure that you have disconnected the furnace from DC power by removing the fuse before sticking a vacuum hose in there.

[Alpine3100RL2115]

Ok NO ROOM FOR A RETIRED INSPECTOR BYE,,,,,
FRANK


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[PerryB]

I don't know why they don't design these things with a filtered inlet. The draft air comes from outside just like a res.furnace. The filter would have to get pretty dirty before it restricted the exchange air enough to make the furnace grid overheat, and then the temp. limit switch would cycle the gas off for a moment. In many RV's the limit switch routinely cycles the burner. Stated as normal in the instructions book.
One thing I did with mine was to put a "wall" of 1/4" mesh wire in front of the furnace. When the trailer was almost new a cellophane sponge wrapper got sucked into the fan and made horrible racket. Fishing it out without removing the furnace was difficult, and of course it happened at 2 in the morning.