Atwood 8525 IV DCLP Replacement

[Old-Biscuit]

Face Plate info
https://www.dometic.com/en-us/outdoo...furnace-136591

I might have missed it but

What exactly is it that your Atwood furnace isn't doing?
Does the fan come on when thermostat calls for heat?
Does the gas valve open/spark electrode fire (Click, Click, Click)?
Does flame come on.......and then goes out?

Details

[EBBOBT]

I am loathe to open the can of worms of where I have been in a search to get my Atwood to be functional. But, because the info you posted has helped me I will try to tell you of efforts I have made to get to where I am. The first step was to find a good article on the internet which could lead me to the solution.....that article was about sail switch which I read and understood....simple straight forward, I ordered a new sail switch and removed the face plate to discover the fan cover was cracked and broken, I started by disassembling the cover, cleaning it spotless, glueing it back together with the right adhesive, installed the new sail switch and tested it.....the furnace fan would come on....but burner would not lite. Must be a problem with the control board, bought a Dino board, installed it...no help. This process continued with item after item of the Atwood furnace ......must be the burner....no, must be the igniter....no, ...............all the way down replacing the propane regulator at the propane tanks....no. All the items I replaced were choices others made in the articles they would write about the obvious solution, all the way up to your info for the Dometic Furnace. All in all, I have saved 59 different hookups to well meaning articles on the internet about obvious solutions. Installing a new furnace has to be a viable solution. Now it is easy for others to chime in that I have taken the wrong approach ....I need to use my brain....well, I'm a retired architect with having designed 385 different buildings (like children's hospitals), so I think I have the aptitude to handle the task....so the problem must be that I have come up short when it comes to the education subtleties needed to problem solve electronic controlled furnaces.
No matter how you see it, I appreciate the key info that looks like a way out of this maze

[Old-Biscuit]

EBBOBT=======Profile shows 2012 RV

SO.......your furnace could have a Timed Delay Relay (TDR)
If it has failed Nothing will happen except Fan start




If no TDR then Circuit Board would have wire connection for 'PWR' and 'BLW'






So which one do you have ???
TDR-----first wiring diagram
'PWR' / 'BLW' circuit board----second wiring diagram


And Which Dino Board did you use?

[justcheckn]

Does the fan come on when thermostat calls for heat?
If not I would suspect the thermostat
If the fan comes on but no flame then possible relay or connection issues as stated in previous post
Had this issue with my last coach
Had 2 heating units
Bedroom heater would do nothing when the NEW thermostat called for heat
Tapped on the thermostat, fan came on , then flame and we had heat, replaced NEW Thermostat with another New thermostat , problem solved
Living area heater fan came on but no flame or heat
Unit had 2 sail switches.
One switch had an intermittent dead spot, would only work when it decided to. Found it by tapping on the mounting area when the fan came on and tapping it got the flame
The person I purchased the coach from had spent close to $2000 trying to get the units fixed. I spent 45 mins in diagnosing the issues and less than $100 in parts
Backup and take a deep breath then clear your mind of the frustration, been there done that, You will figure it out after a few more gray hairs and you’ll feel good about it

[EBBOBT]

Does fan come on when thermostat calls ? Yes, the fan comes on every time. no ticking sound that I could hear, no flame, and light on control board would flash

[EBBOBT]

Old-Bisquit I must have the furnace with a Timed Delay Relay (TDR) because nothing will happen except the Fan start No matter, I've got a Dometic replacement furnace on the way and I'm ready to put the Atwood in the rear view mirror.

[Old-Biscuit]

Dinosaur TDR........$45
Red DC POS from on/off switch goes to TDR then red wire goes to Fan Motor
DC POS from thermostat goes to opposing side of TDR then to ground
*energizes a coil that when heated allows for DC to circuit board via Limit switch / Sail Switch circuit