Furnace won't cycle after initial run

Question

I have a 2006 Glendale Golden Falcon Easy Rider with an Atwood Hydro-Flame 8531 IV that started acting up. It started happening after our trailer flooded (long story) and we came home to an inch of water in the living area and the furnace fan was running even though it was turned off... weird but after drying the trailer for a week I tested the furnace and it seemed to run fine but won't cycle after the initial cycle when it's turned on.
Here's the sequence of events:
- The furnace will start up and ignite just fine when it's turned on
- When the thermostat reaches the set temp the furnace will shut off
- At this point when the room temp drops below the thermostat set temp the furnace will not go through another ignition cycle and just wouldn't do anything even when turning off and on again or when adjusting the thermostat.
-Some time later (not sure exactly how long) It'll fire up, heat the room to set temp, shut off when set temp is reached and will re-cycle again when the room temp drops below the set temp as designed and will operate normally.

Any idea what might cause this issue?

scottg · Answer

I would start by taking the furnace completley apart, cleaning and inspecting evertyhing. It's got to have contamination all through out it. Come to think of it, I would just look for a deal on a new one.
Or, you could turn it into your ins. co.

dougrainer · Answer

IF the furnace was running from the flood, that means the control board got wet and started the fan relay circuit. You need to remove the circuit board and completely check it for corrosion. There are 2 common things that prevent cycle after initial run.
1. Stuck hi limit switch(Most common)
2. BAD logic in Circuit board. Replace the board. IF the Board got wet, It needs replaced. Doug

omri · Answer

So I opened the outside access door and the area looks clean. No signs of water, moisture or corrosion. The diagnostic LED is flashing once every 3 seconds which according to the service manual is a bad limit switch or air flow problems.

Where is the limit switch located?

j-d · Answer

See if This Manual helps.

simplygib · Answer

omri wrote:So I opened the outside access door and the area looks clean. No signs of water, moisture or corrosion. The diagnostic LED is flashing once every 3 seconds which according to the service manual is a bad limit switch or air flow problems. Where is the limit switch located?Go to the following link and scroll down to post #6 by MikeandRuth.  He describes the process of getting to the limit switch along with photos.  His is an 8500-IV but hopefully it's similar to yours.http://www.irv2.com/forums/f54/atwood-furnace-limit-switch-access-231018.html

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Furnace won't cycle after initial run

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