I have replaced to mother boards on a 2018 Atwood gas furnace in less than a year .Is there an inherent problem with these circuit boards ? .Furnace will run for about 45 seconds won't ignite and the shuts off . Waiting for camping world to order another one

Have you tried a Dinosaur board instead of the OEM boards?

Welcome to the Escapee forums!

Are you absolutely certain that the problem is the circuit boards? There are several possible causes for the symptom you mention that range from things as simple as too low voltage in the direct current supply to as expensive as a failed circuit board. If you do get another circuit board, I strongly suggest that you take the advice of Dutch and use one from Dinosaur Electronics. The circuit boards that they supply have a better warranty and they cost less than the OEM boards of most RV appliances. 

On the issue of an Atwood furnace, I don't have experience with one built in 2018, but have had much experience with them and have found them to be generally of good quality and long reliability. 

Typically when an RV furnace (NOT all maybe NOT yours??)  t stat calls for heat the blower motor will start, the sail switch makes up, the high temp limit safety switch must be properly as normal closed, and if all that's in place and working after a delay the circuit board will receive voltage, the gas valve opens and the HV ignitor tip (via HV coil/transformer usually on circuit board) starts sparking to ignite the gas. If there's no flame the flame sense safety circuit closes the gas valve.   Some will try 3 times to light before they lock out...…...

 I say all this so you will realize YOUR PROBLEM MAY BE SOMETHING OTHER THEN THE CIRCUIT BOARD but sure it may well be I cant know from here...….

In 49 years of RV ownership and as a past used dealer I often saw faulty ignitor tips (incorrect gap or hairline crack or carbon trace) was the cause of no ignition as well as LOW VOLTAGE or loose or resistive wires, connections  or corrosion or poor grounds. Insure there's good voltage to the furnace and control board and check all wiring and connections and grounds GET A MANUAL AND work through its troubleshooting tips but low voltage or poor or loose or corroded connections or bad grounds or faulty ignitor tips could be the problem. On appliances that used a flat ribbon cable that attached to the circuit boards I have seen where that connection just needs cleaned (caused low voltage to the board)  and on my own furnace recently that failed to light like yours a simple ignitor tip gap adjustment cured the problem.  

Ive never had a Dinosaur replacement board go bad in case it turns out that's what you need...... 

John T  Live boondocked in  North Padre Island Texas

Edited December 5 by oldjohnt

  In my experience with the new style Atwood furnace they do have a board problem.

 I am a Dometic/Atwood dealer.  I have stumble through a number of this style furnaces that have board problems.

 What I have seen is moisture on the board when the humidity is high. And it corrodes the board and or connections.

 I think this is because of the location of the board being located towards the intake area on the blower, next to the burn chamber blower wheel. The opposite end of the heating blower wheel is where the old style furnaces locate the igniter board. And the old board location had interior air flow over it but at a much less restricted area. Then lowering the moisture separation problem.

  With the location of the board where the factory has it, makes the moisture in the air form a vapor trail. Then it condenses on the board. 

 I have seen replacement boards on the new style furnaces fail in two months time.

 Now I have done some testing on old style Atwood furnaces and discovered the the seal on the inside of the exterior cover may not seal completely. I have two old style Atwood furnaces in our fifthwheel and they both leaked air past that seal that separates the interior from the exterior air.

 I then installed a screw to hold the center of the cover tight against the seal and the brace it seals to. Pull your cover and see if the seal fits tight or not.

  I have not tested any new style furnaces for that air leak.

  I getting close to retirement so working on the new style Atwood furnaces has ended for me. I had some discussions with Atwood on the problems that unit has so I will not work on them at all.

  Now if I was stuck with one of those I would?

1. Try a Dinosaur board.

2. Try to talk to Dinosaur about the problem.

3. Locate the board at another location.

4.  My personal thing to do is to buy a old style furnace and install it where your original on is located.

   If you find a solution please let the members on this forum know what you did.

Safe Travels,   Vern

Vern, great info thanks for posting !!!!!!!!!

DITTO on your advice to Try a Dinosaur Board, I've yet to ever have one fail yayyyyyyyyyyyy

John T

I've installed around 50-60 Dinosaur boards in various appliances over the years, both my own and other people's. I've only once returned a board for replacement, and that one had quite clearly been damaged in shipping.

  I just want to clear up this situation about the igniter board.

  The new Atwood furnace is what I think causes the board problem. Not the board itself. As I have removed the cover on the outside of the furnace and there can be moisture on the board. And how did that moisture get there.

  That is correct that I have seen water on the igniter board.   No water lines in the area.

  Now I think they may have changed the exterior cover design. To help with the situation.

 Just my thoughts,,    Vern

  On 12/7/2019 at 5:52 AM, Wrknrvr said:

Now I think they may have changed the exterior cover design. To help with the situation.

It sounds like they needed to do something! I was not aware of the problem with the current Atwood furnaces and have always preferred them over Suburban but this could change that. Thanks for making us aware of the problems, Vern.

 I believe the new model I am talking about is a AFMD series.

  They maybe some with different vent openings . This may be an attempt to correct the problem.

 If you search the net for problems on this model you can find some more info that is interesting to read..

 trying to give help for the problem,    Vern

Vern, based on your observations and experience it looks like ANY brand of control board would fail under those (moisture) conditions !!!!!!!!!!

Thanks for the technical info, it could help others.

John T

I wonder if clear coating the board would help. Masking the connection points of course...

  On 12/7/2019 at 10:42 PM, Dutch_12078 said:

I wonder if clear coating the board would help.

Good afternoon Dutch, I would say if it keeps water off the sensitive components it could sure help, HOWEVER the answer depends on there remaining sufficient heat dissipation as coating would obviously affect that.  Thermodynamics and heat transfer was NOT my cup o tea when studying electrical engineering so take this with a grain of salt lol

Best wishes, John T  Live beach camping in Port Aransas Texas

  On 12/8/2019 at 3:22 AM, oldjohnt said:

Good afternoon Dutch, I would say if it keeps water off the sensitive components it could sure help, HOWEVER the answer depends on there remaining sufficient heat dissipation as coating would obviously affect that.  Thermodynamics and heat transfer was NOT my cup o tea when studying electrical engineering so take this with a grain of salt lol

Best wishes, John T  Live beach camping in Port Aransas Texas

Heat dissipation was why I was thinking clear coat instead of potting the board, John. That could still be too much insulation, but I do note that Dometic uses potted ignitor boards on their water heaters.

  Dutch, I once had an older Onan Genset (before they became Cummins Onan) with a circuit board that went bad IT WAS FULLY EPOXY ENCASED and Onan charged something like $500 for them grrrrrrrrrrrrrr I called Dinosaur and they didn't make a replacement nor did they know of anyone who could disect and repair them. After looking and shopping for new or used I finally broke down and bought one BUT HEY IT FIXED THE PROBLEM what ya gonna do especially when on the road...………..I've owned RV's over 49 years and unless you buy say a Prevost or similar and pay a small fortune the darn things are built cheap n flimsy and no matter how old or new it seems were (or me at least) always having to repair them  grrrrrrrrrrr. Theres no free lunch but I still wouldn't trade this lifestyle for anything. A buddy went to Florida last year rented a Condo and sat in it or at the beach 2 months, never talked to anyone else all the doors are closed of course,  and got so bored he came home HEY IM NEVER BORED with buddys in the RV Parks and Antique Tractor Shows (where Im an exhibitor)  and Bluegrass Festivals all winter wooooooo hooo

Best wishes Dutch and others

John T