Furnace help

[melvonnar]

I just returned from camping and I need some help on how to remove the furnace out of my motorhome. I have a 1999 coachman catilina class A,
the manual says EXCALIBOR 8500-II, I believe its a Duo-Therm but I'm not sure. The heat and cool thermostat is a Duo-Therm, so I'm guessing the furnace is a Duo-Therm.
This furnace has only been used very little and has always worked well; all of a sudden there was a vibrating noise coming out of the furnace, I shut it down real quick when I restarted it it started and made a thudding noise then ran ok, after that each time it started it made this thudding nose; and once in a while it made a loud vibrating noise. When I shut it down, then restarted it again,it would make that thudding noise, then run ok.
I want to remove the furnace from the motorhome and see if I can locate the problem.There is 4 screws on the outside of the motorhome where the hot air comes out.
theres a connector on the furnace on the inside of the camper, i also know that I'll have to disconnect the gas line the the furnace.
Question:
does the furnace come out from the inside or the outside?

[cowboy2]

before removing the unit i would get it checked out by a tect,it maybe just need an ajustment or needs cleaning

[melvonnar]

Quote:

Originally Posted by cowboy2 before removing the unit i would get it checked out by a tect,it maybe just need an ajustment or needs cleaning

good advice; but:
I'm a do it yourself guy; just like doing it myself.
Just sounds like something loose in there.
everytime I take my motorhome in for repair, it seems I wind up redoing what I've paid for.
I just want to get this thing out so I can look at it. I've got nothing but time, so I'm in no hurry; I'll get this thing out one way or the other.
my first though was a mouse got in there and the fan got him.
I've had mice problems in the past.

[Tom-NC]

HI,

I haven't had my furnace out however I believ they all come out from the outside. To be sure why not give the coach manufactuer a call and ask them and then give Atwood a call tell them of your problem and see what they say.

It is nice to be able to repair things yourself and I do most of the work myself too unless it is beyond my capacity such as removing wheel lugs that have 450 lbs torgue on them.

Play it safe also and no sparks around the propane line even though it may be turned off.

Good Luck

[Hooligan]

melvonar: Excalibur 8500II furnace is a HydroFlame, made by Atwood. (My 8500IV Model8525 also has a Duo-therm thermostat) The outside cover removes but then the unit is held in by about a dozen screws around a plate and gasket on the outside wall. There may also be screws into the floor inside, and the ducting. The unit when fully disconnected slides out. However with just the outside cover removed you can inspect the blower housing and motor area and sometimes critters can get in there. Mice through the ducting, mud dauber nests on the blower wheel, etc. Your description sounds like something out of balance.

Use caution going deeper into the furnance, it's recommended a qualified tech work on the gas lines. FWIW, I have removed my furnace, replaced the blower and motor and repaired the under floor ducting.
If this is your furnace, we are on the right page. http://www.ntpdistribution.com/PDF/V...r8500IIser.pdf
hope this helps

[scenic route]

Sure sounds like there might be something in the fan... Sometimes getting blown out into the exit duct and then falling back into the fan on the next start up to give you the vibration. Could be a loose fan on the motor shaft.

From a quick on line look, some of the Duo-Therm models look to be removed from the outside(one site says that they can no longer get parts for Duo-Therms). Another site showed an Atwood Excaliber 8500 series furnace that looks to be removed to the outside as well. Could not find a parts breakdown for either. Someone else may come up with a link. Good luck...Bob

Just saw what Hooligan posted...there ya go! : )

[Hooligan]

Found an detailed Atwood service manual, it's for the 8500 IV but good parts layout and troubleshooting. I think the basic furnances are the same but the part numbers will be different for your specific model.
http://bryantrv.com/docs2/docs/hflamefurn04.pdf

FWIW the site "bryantrv" has a wealth of info on service and tech manuals for most appliances Site Map Page 1 - Generated by www.xml-sitemaps.com

[melvonnar]

Quote:

Originally Posted by Hooligan Found an detailed Atwood service manual, it's for the 8500 IV but good parts layout and troubleshooting. I think the basic furnances are the same but the part numbers will be different for your specific model. http://bryantrv.com/docs2/docs/hflamefurn04.pdf FWIW the site "bryantrv" has a wealth of info on service and tech manuals for most appliances Site Map Page 1 - Generated by www.xml-sitemaps.com

Yep: it's an atwood

[melvonnar]

Sometimes you get lucky:
I removed the panel one the outside of the motorhome; right inside was the fan motor and a small inspection hole for the fan motor; the fan was slightly loose and I gould get to the set screw to tighten it. noise is gone.
once in a while you win some.

[Hooligan]

Good work!!!