Atwood furnace blower problem?

[frodo]

My furnace is a 7920-II serial # 1639234. All has been well until this recent cold snap. On a very (for nc) cold day (15 degrees) the furnace stopped due to running out of fuel. (Middle of the night of course) I went outside and flipped the fuel switch to a new full tank and restarted the furnace.

It was producing very little heat so I lit a burner on the stove and the flame was very low, about half the usual flame height while the furnace was running. Turned off the burnerand left the furnace running and went back to sleep hoping for the best. Woke up in a cold TT - furnace was not running.

After checking the tank and finding it full I moved all the switches open and closed several times thinking maybe something was frozen. Went back inside and lit a stove burner - viola - strong flame. Turned the thermostat up to relight the furnace and the blower ran at about half, or slower speed and stopped after 10 seconds or so with no ignition.

Much warmer weather now and the blower has the same problem. Starts at a very slow speed and then stops after a few seconds. Control board shows one blink at startup. One blink code reads "input air restricted" or something to that affect.

Any ideas on possible solution - other than write a check???

By the way, this Sunny will be for sale later this year. Have been living in it while I remodel my new (to me) house.

Clark

[mainah]

Inside of the furnace is a "sail" switch it is actuated by air flow if the switch does not "proof" the gas valve will not open allowing the burner to light. Bee's nest in the air intake outside, low battery not allowing the fan to turn fast enough or a bad blower motor can cause your problem.

[Gene]

Yup, what mainah said above ^ ... particularly the battery voltage.

[frodo]

Originally Posted by mainah

Inside of the furnace is a "sail" switch it is actuated by air flow if the switch does not "proof" the gas valve will not open allowing the burner to light. Bee's nest in the air intake outside, low battery not allowing the fan to turn fast enough or a bad blower motor can cause your problem.

Thanks for the response Mainah.

I'm familiar with the "sail" switch function from the schematic but as with most things installed in a TT finding the actual part and getting access to it is a PITA. The "outside" air in a 2263 is actually inside under the cabinets. I can see it clearly and turned the fan cage some by hand. Nothing seems to be blocking air flow. A bit stiff to turn so could be a bearing or maybe the voltage. The actual motor is so hidden behind cabinet material that I would prefer to postpone attempting to remove it for inspection and testing until I try every other suggestion.

I may be able to track down a place to test the voltage on the control board. At least something to try. The other DC voltages around the TT are up to spec.

Any other thoughts on making the fan motor run faster??

Clark

[mainah]

Actually the heaters are not hard to remove and it sure beats trying to work on them where they are. Yes first check the voltage at the battery and the board usually the boards are not too badly hidden. Do you have the camper plugged in?

[frodo]

The board is fairly easy to access. Just remove the cover and two screws that hold it in place. I'll try checking the voltage today.

Yes the power is connected and all other things are working ok. I'm using an electric heater to keep the place warm each night so I have time to work on the furnace. Still it looks like a PITA to remove.

Anyone ever removed one from a T-2263? And if the motor bearings are toast where can one find a replacement?

[frodo]

Finally got around to testing the blower voltage and it is solid at 12.5 volts. The blower starts with a "rotational" clicking/thumping noise and never get over half speed, or so. Turns off after 15 seconds with a click - probably the sail switch shutting it off for lack of speed/blowing power.

I'm guessing a bearing is shot in the blower motor and may need replacing. Any known sources on a "new" blower motor? Or ideas on how to fix this one?

[noralee]

hi frodo,
wishing you luck fixing your furnace.

i am also in nc, and during the cold snap last week i woke up also in a freezing camper...i had run out of propane middle of the night. at about 10deg. or so, i had to get up go outside and switch the tanks over.
glad for warmer weather. now, anything above 20 seems 'not so bad.'
good luck and warmth through the winter,
nl

[frodo]

Why is it that the propane always runs out in the middle of the night? Seems like it knows!!!! Where u at in NC? I'm in Goldsboro now. Spent one winter in New Bern - nice town.

Frodo

[noralee]

i'm about 20 miles nw of asheville, and new to the state, just a few months here. i'm up in the mountains though, so i get more snow and cold than asheville. yes, not only in the middle of the night, has to be in record breaking cold
i woke up so cold and it took me a minute to realize what happened. i'm using a small electric space heater now since i wasn't able to get a large propane tank here for the winter. filling up the smaller ones even as 'refills' is pretty expensive so not much cheaper i don't think. the furnace works better though. my camper is pretty small and it heats up so quickly with furnace. only a 1350.

[mainah]

You can take the motors apart they use bronze bushings that were impregnated with oil of course they dry out over the years a good cleaning of the shaft and some light grease and your good to go for a few more years.

[frodo]

Asheville is a wonderful location in the summer. Winter is another story unless you're into skiing and snowshoeing. I left New Hampshire to get away from all that cold. Brrrr.

I'm using an electric heater while I repair my furnace and it heats this 2263 nicely. Ordering a new motor ($84 plus shipping) so the furnace should be back in service in a week or so. This 2263 uses up a 30lb tank of propane every two weeks in winter. $20.28 per refill so not bad for furnace, stove, and hot water. And winter is much shorter here than Asheville area. Camellias in bloom and daffodils coming up now,

Good luck this winter.

Frodo

[frodo]

Originally Posted by mainah

You can take the motors apart they use bronze bushings that were impregnated with oil of course they dry out over the years a good cleaning of the shaft and some light grease and your good to go for a few more years.

Already have the new motor on order. If the take apart and re-oil works on the old one I'll clean it up and offer it on ebay for the next unlucky Sunny owner. At $84 for a new one a "refurbished" one should bring $45 or so on Ebay. I would have paid that if available.

Frodo

[frodo]

Originally Posted by mainah

You can take the motors apart they use bronze bushings that were impregnated with oil of course they dry out over the years a good cleaning of the shaft and some light grease and your good to go for a few more years.

Take a bow Mainah. Was warm today so I decided to dismantle the furnace and try your suggestion of re-oiling the motor bearings. Real PITA to get the blasted thing out where I could work on it. Thankfully I took many digital photos of the dis-assembly process, especially the wiring.

It comes apart rather easily and the fans slipped off the shafts with a little encouragement (and a few curse words). The ends of the motor are a bit more difficult to remove to access the bronze bearings. Actually I gave up on the exhaust fan end and just pried it up enough to inject some oil into the felt? around the bushing. The other end came off easily so it got more oil on the felt? and the shaft.

Just to be sure the fix worked I tested the motor using my car battery and let it spin rapidly for a few minutes. Re installed everything clicked on the thermostat - and NOTHING!!! No fan spin, no voltage on the board.

Pulled it back out far enough to check all wiring and everything was hooked up correctly. (those digital pics came in handy) Hooked everything back in place and decided to try thinking beyond the furnace. Yeah! Check the fuses stupid!!! Replaced the blown fuse and all is now well. Don't know when the fuse blew but it happened while I was futzing around taking it apart and was not the original problem.

Thanks again for that thoughtful, experienced $84 saving suggestion. I was able to cancel the order for a new one before it shipped.

And yes if anyone asks - it took a long time working in such a small space. Maybe six hours figuring it out the first time. Could do it again in 30 minutes. Ain't experience wonderful!!!!

Frodo

[Gene]

Originally Posted by frodo

..... Maybe six hours figuring it out the first time. Could do it again in 30 minutes. Ain't experience wonderful!!!!...

Ain't that the truth!!

Glad to hear you got it working and HOW you got it working. That may help others here.

[frodo]

I can provide pics and some advice if another Sunny owner needs that level of help.

It really is easy when you know how!

Frodo