Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 09, 2025 ...

Today I changed out the front (and only) air return register for the furnace on our 99' U270. It required a bit of modification of both the Oak register that we bought online and of the opening, but I believe it was worth it. I gives a larger air intake as well as a removable filter. The grill swings out for changing. Bonus feature is that it makes the whole furnace area much more accessible from the inside of the coach. It came with a relatively crude but washable filter screen, but I found a source on line of ready made filters of various grades. The area under the furnace was incredibly filthy with an accumulation of dust and dirt. I plan on getting the higher rated (as in finer filtration) after I clean the ducts. The main reason I did the swap was just because the metal grate looked tacky as I have been busy doing the rear half of the coaches' trim for the new bamboo floor. Pics attached. If anybody would like more details, just let me know and I will post more details such as a link to where we bought the register etc.
Don

Don,

Atwood furnace manual specifically says NOT to use a filter in the return air duct.  The blower apparently doesn't have enough reserve capacity to handle a filter, and heating efficiency of the furnace will be impaired.  My guess is that with lower air flow than design spec, it will be hitting the high limit temp switch and cycling on and off a lot.

I had the same reaction that you did when I saw the dust build up in the furnace area, but apparently can't be helped with this furnace.  Atwood suggests using a separate (freestanding) air filter.

Low air flow because of an air return restriction will (or should) cause the SAIL SWITCH to remain open so the furnace (propane valve open and igniter spark) will not come on.

I see no problem with an air filter IF PROPERLY DESIGNED AND CLEANED.  The key here is to have more surface area to offset the restriction in the filter AND to keep the filter clean.  I suspect the lack of cleaning by most RV'ers is the reason for the recommendation against the filter by Atwood.

Filter or not, your new grill looks great, and the local decoration department is asking engineering where you got it? (suspect one is in our future too...)

Thanks Don,

Just ordered one!  Great idea!