Access to Furnace Fan

[JimHam]

My 2014 Cougar RBS21 has a noise in the heating unit. Sounds like something is rubbing against the fan. Removed the interior grill located below the fridge but the fan is on the outside end of the unit. Opened the outside grill over the furnace but no fan access that I can see there. The sound is coming from the two exhaust ports on the exterior of the unit and there is hot forced air coming out of them. I suspect wasps or mud daubers have somehow gotten in those ports and built a nest against the fan. I bought the wire covers for the ports but not sure if the previous owner kept them covered. Anybody know how to access the fan in the heater? I am afraid this might be a dealer job since it seems I would have to remove the unit to get to the fan.

[chuckster57]

If your exterior only has the two ports, then you have to pull the furnace out of its "box" from the inside. Once you take the grill back off, look for the gas line and wiring harness.

TURN OFF the propane at the tanks, make sure to label the wires. You have to remove the cover plate to get to the screw that anchors the furnace.

Use 2 wrenches to remove the gas line so you don't damage the hard line in the furnace.

Once you get the furnace out, you can start taking it apart to access the fan. Pay attention to where the screws go and their length. Make note of routing of wires. Might be a good idea to take pictures for reference.

[B-O-B'03]

+1 to what chuckster says.

I had to remove my furnace, after water leaked from a cut pipe and ruined the electronic control board.

It was really easy to do, the ducting just turned a little to disconnect and there were only a couple of screws into the floor hold the unit in.

I had to remove the outside vent to reinstall it and get the flue pipes re-seated correctly.

-Brian

[JimHam]

Chukster, I do have the exterior access panel that I removed to try and get to the fan. All the wiring is on the exterior side. There is an inside, louvered panel just below the refrig that allows access to the inside. All I can see when I open these panels is a metal box with ducts attached to the inside and wiring on the outside. I removed the ducts on the inside and then removed the end panel of the metal box and saw just the heat exchangers so I put everything back and went outside. There is a black fuse box mounted on what appears to be the end of the heat exchanger chamber but I could not see any way to remove that end of the metal "box" I will take another look at it this weekend and post up some pictures. Got a deer hunting trip coming up next week and heat would be nice. The furnace works but the fan is very loud and I don't like the idea of something being in the fan that could damage it or even start a fire.

[chuckster57]

The heat exchanger comes out of the metal box. If the exterior panel is a large rectangle then the heater comes out from that side. If the outside panel is a square with the two holes then the heater comes out from the interior.

[JimHam]

Yeah, the exterior panel is a large rectangle. The hot air vents are separate and come out the side of the camper below the rectangular opening. So I guess I will have to take all the wiring harness off and figure out how to bring the unit out of the side of the camper. It sounds like the blower fan is in the unit on the right exterior side.

Well, I just got on YouTube and found a video of how to remove the furnace. The guy was removing a furnace from a Keystone and the unit looked very similar to mine. It does come out toward the interior of the camper. That explains why I could not figure out how it could come out of the exterior opening - it doesn't. When in doubt - YouTube!

[bobbecky]

Depending on the model of furnace, some are fully accessible from the outside. Our rig has the Atwood 8535-IV heater with the outside cover. In the manual, it states: Serviceability - This entire furnace is serviceable without removing it from the RV. Therefore, there is no need to bench test it. All
components are accessible by merely opening the access door. We strongly recommend trouble-shooting the furnace while it is
installed in the RV.

Look inside the furnace for a label, which will give you the model number. Then you can go to this site, for Atwood heaters, to find the correct manual for it. http://www.atwoodmobile.com/furnaces.asp

[JimHam]

Unfortunately my unit does not seem to be serviceable from the outside. When the plastic door is removed on the outside all you see is some wiring, a fuse box and behind that a piece of what appears to be an insulating panel made of foam sandwiched between layers of aluminized material. Can't even see how it could be removed. I am going to try and pull the unit out toward the inside of the camper and then I am hoping all I find is some leaves or wasp nest in the squirrel cage blower that is easily removed.

[JimHam]

After watching a couple videos on youtube I dove in and pulled the furnace out of the camper this morning. Couldn't find anything in the squirrel cage but upon closer inspection found the end of the plastic vanes were rubbing on the blower housing. Pulled the furnace guts out and got into the motor enough to find that the set screw that holds the fan on the motor shaft was gone. Faced with a long trip to the hardware store and the loss of a couple hours of work with no guarantee they would have the set screw I took a magnetic screw retriever and ran it all through the furnace cabinet. Pulled it out and lo and behold the set screw was stuck on the magnet. Cleaned everything, assembled, (with lock-tite on the set screw) reinstalled and she's working like a charm. No more noise! Now I can sleep warm on the deer hunt in Illinois next week. :thumbsup:

[hankaye]

JimHam, Howdy;

Thanks for the follow-up. I'm guessin' here but wouldn't be surprised
if you celebrated with a cool adult beverage or 2, well deserved they'd be.

hankaye