For the guys/gals that think most RV repair is rocket science, I submit a little DIY on RV furnace repair, Atwood hydroflame to be exact. My blower motor bushings/bearings were screaming like a banshee last time I used it, so time to replace it while its still above freezing.
First things first, unhook the batteries, and unplug the AC. Even though the batteries are unplugged, the converter will still supply 12v and low current throughout the system. Also shut off or remove the propane tanks. We're not gonna play with the gas, but better safe than sorry.
First find the furnace. Looks like this from the outside....
Will need a few common hand tools, like philips and standard screwdrivers, fractional allen wrenches, and such. Couple things to make life a little easier, a 1/8 T-handle allen wrench and a Robertson bit (square) screwdriver. One of these should be in every RV, as just about every screw is of this type...
Remove the outside metal cover using the square tip driver (see, needed it right off the bat). Depending on model there may or may not be a plastic cover underneath. If so, remove that also. Should look like this.
Remove the 4 scews holding the black plastic fan/motor cover, and carefully remove and let hang. Some may have a block with 4 wires screwed to the outside. Either unscrew it, or remove the wires (Don't forget where they go, this is where the camera comes in handy). There is also a on/off switch, circuit breaker mounted in a hole in the upper left corner of the plastic cover. The wires need to be removed in order to remove the cover. Pay attention, as there are two wires on one side, and they are kinda short. The motor and fan should be exposed. This is a good time to remove the control board. GENTLY remove the connector from the board, and then the high voltage wire. Loosen the wing nut in the top corner and gently slide it out. These things are expensive and hard to find (factory replacements) so remove and set aside in a safe place.
If you look closely thru the fins of the fan about in the middle you will see a 1/8" allen head set screw. Loosen with the T-Handle and slide the fan off. More than likely this has been on for awhile so a little careful force might be needed to slide it off and out.
And walla, the front of the motor. We are half way there...
Remove the burner tube. There is a wing nut in the upper corner, loosen and slide the burner tube out. Need to do this to get to the combustion fan.
There is a metal band holding the motor in place. Remove the screw, spread the clamp a little. Wiggle the motor and remove the metal piece. This piece makes sure the motor is against the back wall and doesn't spin. With the burner tube removed, you can see (barely) that there is a clamp ring holding the combustion fan to the motor shaft. On mine there was a small access hole in the shroud near the wing nut to stick a 1/8" T-Handle allen wrench. It doesn't line up very good, but the alternative is a small allen wrench and skinny hands to loosen the allen bolt and slide the ring off.
Now here is the most difficult part. This fan gets more heat, and thus a little more corrosion. Which means it probably ain't just gonna slide off. Grab the motor, and wiggle, jiggle, and pull. Be patient, it will come. (member quotes here I come
) Took about 45 minutes to wrestle it out. Be careful as the wires are threaded thru a hole in the metal clamp ring and will get hung up as you remove the motor. Finally its out.
Assembly is in the reverse action, and as I said earlier, not as difficult as it seems. Use canned air or low pressure from the air compressor to blow off the dust and dirt from the fan blades and the control board. Careful, don't go crazy with the air pressure. The hydroflame furnace is the easiest to do, the suburban furnace is a major pain. The suburban brand has to be completely removed from the RV as the actual framework has to be removed for access to the associated parts.
When going to get replacement parts, you will need the model and serial number of the unit. This will be on the sticker on the black blower motor shroud along with a smaller sticker with the serial number. Get all the numbers. For example my model number is 8940-lll-DCLP. There are many variations of each family of furnace models. For example mine is a 8900 series 3, DC power on LP gas (mine was also made in an AC, natural gas version). Also take the parts with you to make sure that the new ones match up with the old ones.
Hope this helps out. RV labor rates are expensive, and most things are not hard to do at home with a little direction.