Don Don
Pleasant Grove, AL {Suburb of Birmingham}
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Joined: 05/21/2005
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My Atwood Model 8525 has a problem. The furnace will come on and light but goes out. I can hear the ignitor still clicking after it lights. It shuts down after 3 attempts. Any Ideas?
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John&Joey
Northern MN
(Baby it's cold outside)
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Joined: 05/20/2007
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Here is a CLICKY LINK to the service manual.
They have a good trouble shooting section in it. I have the same furnace and two things I've noticed is the connection to the control board needs cleaning (lightly with a pencil eraser) yearly. Also if it's been sitting all summer and it's a little wet outside the first time trying to get it lighted is a bugger.
What I do that first time is light the oven and run the fridge on gas for a few minutes (then turn them off.) This will help purge any air in the line. Then I do what you're doing. Only thing different is after the third attempt to light, I set the temp way down and wait 30 seconds, then I turn it up. This will start the process all over again. This season it took 15-20 attempts before it took off. It's now running as we speak even.
My belief is as it sits all summer the heat sensor gets some corrosion on it making sensing the flame difficult. Once it runs for awhile the corrosion is burnt off. It's that much harder if it's damp outside for the sensor to sense the flame that first time.
As they say, your results may differ. 
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tonyandkaren
pennsylvania
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Clean the connections on the control board first but if that doesn't work you may be getting a voltage drop at the thermostat. To check this remove the thermostat and twist the wires together. If it works okay with the wires twisted , get a new thermostat. The one that came with our Atwood furnace wasn't very good. Make sure that that it uses a mechanical switch , not a mercury switch.
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Don Don
Pleasant Grove, AL {Suburb of Birmingham}
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tonyandkaren wrote:Clean the connections on the control board first but if that doesn't work you may be getting a voltage drop at the thermostat. To check this remove the thermostat and twist the wires together. If it works okay with the wires twisted , get a new thermostat. The one that came with our Atwood furnace wasn't very good. Make sure that that it uses a mechanical switch , not a mercury switch.
Not that. I have 2 furnaces and the other one is fine.
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jpfx
Columbia SC
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mine got a piece of grit in the jet. once I took it apart and removed it, it worked perfectly.
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Texans
Texas
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Try blowing the dust and or lint(if any) off of the control board and check those plug-in connections to the board. worked for me.
Richard
Richard and Annell,
03 35' Dolphin (Workhorse W22), 02 4x4 Tracker,
Brakebuddy
Texas
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tporter
Southern California
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I had this problem. I have two furnaces on my coach, I took the circuit board out of the good furnace and put it in the one that didn't work. Furnace worked, my circuit board was bad.
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Kirk
Livingston, Texas.
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Don,
My experience has been that when you have a situation where the igniter continues to spark then the unit shuts down, it is an indication that the circuit board is not detecting the heat of the burning propane. When that happens the furnace will go into lockout and must be turned off and back on to try again.
The Atwood furnace uses an igniter where the probe that supplies the spark is also a metal compound that when heated by the burning propane it will create a very small voltage. Between the sparks the circuit board monitors the lead to it seeking to detect this signal which is measured in micro-volts. If it does not see the voltage, it sends another spark. Once it has tried three times, checking for heat after each spark(a few try five times), it then assumes that the gas did not light and goes into lockout.
The signal is very small so the first thing to do is to remove the lead from the circuit board that goes to the probe and use a contact cleaner on it's connector and also clean the connection on the circuit board. While you are at it, remove the probe and clean it carefully and check to make sure that the gap is about 1/4" and that it is directly in the path of the flame when the burner lights.
If this doesn't help, the next most likely is that the probe is bad. They are not very expensive, are pretty easy to replace and are readily available at most RV parts houses. This is where most RV techs will look next.
Least likely, but still a possibility is that the circuit board is failing. If you do need to replace it, I suggest that you use a replacement from Dinosaur Electronics as they make a better quality board with a three year warranty, while the one form Atwood only has a one year warranty.
I give this, assuming that you actually saw the flame of the burning propane?
Good travelin! ........Kirk
Professional Volunteer
www.adventure.1tree.net
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Don Don
Pleasant Grove, AL {Suburb of Birmingham}
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Thanks for all the help, problem solved. It was just soot and need cleaning. Thats all.
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John&Joey
Northern MN
(Baby it's cold outside)
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Don Don wrote:Thanks for all the help, problem solved. It was just soot and need cleaning. Thats all.
That's great news. As much as everyone wants to swap out the board ($100+) or the sail switch, it seems on this model it's the sensing of the heat that is the Achilles heel.
I often wonder if a Dinosaur board is just better at sensing a flame then the OEM. That might explain the success people have when they replacing the board.
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