Furnace Lighting Question

[salem]

Rained really hard all night and throughout the morning. DW tried lighting the furnace to take the chill off. The blower came on and the furnace started but shut down after about 10-15 seconds. She tried again a couple of times with the same results. About an hour later I tried it again. It lit perfectly the first time and ran without any problems. Later, in the afternoon, we tried it again. It started once, shut off, and then lit the second try without a problem. I mentioned in the first sentence that it has been raining heavily, just in case their could be a moisture problem? Both propane tanks are full. Ideas? Regulator? Electrical? Thanks. (when I said it lit after the second try, I mean it will try, I believe three times, before it shuts off) Note* The furnace is made by ATWOOD. Also, I replaced the converter in July so I believe my batteries are fine.

[tommykelly]

sadly you are right...I should have said dometic ....I have found over the years Atwood a much better water heater and furnace..except the blower motor... than Suburban...that is just me...

when I called Atwood in the past for tech help..they were very helpful and friendly...

I don't like these companies merging into one giant corp.....no competition means more cost and less quality...and a lousy attitude...take it or leave it...not good....

[Chris_Bryant]

Actually, Dometic now owns Atwood- Coleman (RV Products) owns Suburban.

[tommykelly]

Same thing on my Atwood 8535 III.....I took the 4 screws out and pulled the housing away from the large blower...then "very gently " worked the sail switch back and forth and put it back...

So far my burner has remained on...I know I will have to order a new switch sooner or later..

Also...Coleman now owns Atwood furnace division ...they have made changes to furnaces..the exhaust, the gas inlet ..and the access doors...plus many other things....

[wa8yxm]

I have that problem with my water heater.. But there are a few suspects.

The flame sensor rod (Clean it, make sure the gap is set properly)
THe wires connecting to the control board (Make sure connections are clean)

The control board itself

Also the burner. Make sure (Observe visually) it is properly lighting

NOTE: That wire .. during ignition, carries about 1,000 volts by estimate.

During flame sense less than 1/2 volt

[bid_time]

filthy beast wrote:

ScottG wrote:
Often times the flame sensor is so covered in soot that it's insulated enough to not work. I have repaired four of them by using carburetor cleaner or a small brass brush. Just put a rag under it to catch the excess cleaner if you go that route.

I would be concerned of my flame sensor was covered in soot. Furnace not burning properly.

Nothing to be concerned about at all. If you read your maintenance manual for the furnace they recommend cleaning it once a year.

[filthy_beast]

ScottG wrote:
Often times the flame sensor is so covered in soot that it's insulated enough to not work. I have repaired four of them by using carburetor cleaner or a small brass brush. Just put a rag under it to catch the excess cleaner if you go that route.

I would be concerned of my flame sensor was covered in soot. Furnace not burning properly.

[salem]

Thanks guys, this will give me something to look at.

[ScottG]

Often times the flame sensor is so covered in soot that it's insulated enough to not work. I have repaired four of them by using carburetor cleaner or a small brass brush. Just put a rag under it to catch the excess cleaner if you go that route.

[John_Joey]

I'm guessing that you may have a crack in the ceramic of the sparker. After it sparks the probe is used to sense a flame. If it does not sense a flame the computer shuts it down. A crack in the ceramic during very wet conditions will wick away that minuet amount of flame generated current telling the computer that a flame is not present.

[Artum_Snowbird]

There is so much self help info on google, but it really does help to know a model number. Just put in the info, add the word troubleshooting, and you will likely be able to save yourself a bundle by figuring it out yourself.