Atwood Furnace problems

Broke down and took it to the dealer for repair, since its still under warranty. So guess what, it works perfect for the dealer!!! I asked them to go ahead and replace the circuit board just so I won't have to take it back to them next spring but on no "it works fine" they said. I guess my motorhome will have to burn down before they will do anything.. :(

Question (You can tell if you are outside the MH when it tries to light) does it succeed in lighting or not?

Mine acted rather weird a few years back.. I had to reset the gap on the points,, It worked great after that for about a year.. This is the 2nd DSI furnace I have worked on (The other was my parent's oil fired house furnace) and on both of them the points were set farther apart than the manual stated they should be.. Re-setting the gap fixed the home unit 100% far as I know (Parents both gone now) it's still working.. .The RV's lasted a year after re-setting. Then it developed a new problem

With this new problem it would light 3 times, It actually lit, I could hear the change in tone and feel the heat.. But it would not stay lit, It shut down

Turned out to be a bad control board (More in a sec)

Other suspects are the thermocouple (Which may also be an ignition point) make sure it's clean and operating (If you need I can tell you how to test but .. Well, better if you already know)

Or the connecting wire,, Check for rusted/corrorded connections.


The mother board.

I went with a Dinosaur board replacement

OEM 250 dollars plus S&H

Dino 108 in my hand

Better built (The quality is impressive) and from what I can tell better designed as well.. I have a theory as to what killed my board and Dino Seems to share my opinion as they included a protection device on their board.

wolfe10 wrote:

Bird Freak wrote:
If you have the 8535 gen IV series you have no thermocoupler. Mine did the exact same thing with the same code you are getting and it was the board.

Yes and no. Yes, there is no separate thermocouple. But, the ignitor serves that function (sensing temperature) for the PC board.

Here is an Atwood troubleshooting manual from 2003 O(need to verify it is the same as yours):
http://bryantrv.com/docs2/docs/hflamefurn04.pdf

On page 30:

BURNER IGNITES BUT IGNITION SYSTEM “LOCKS OUT” AND TURNS BURNER OFF
Low gas pressure
--------------------------------
Set pressure to a minimum of 11 ? W.C. with all appliances running.
Replace regulator if not obtainable.*
Exhaust blocked
----------------------------------
Clean exhaust.*
Combustion air wheel loose
------------------
Reposition wheel and tighten
Electrodes out of adjustment
------------------
Adjust electrode according to furnace specifications.
Electrode defective
------------------------------
Replace electrode.
Circuit Board defective
--------------------------
Clean plug contacts. If still defective, replace. (Check on board tester
when possible).
Flame sensor wire between electrode
------
Replace wire
and circuit board defective
Air leakage at gaskets
--------------------------
Replace gasket
Defective heat exchanger
----------------------
Replace heat exchanger

Thanks for every ones advice. I will do some more checking this weekend on it. :)

Bird Freak wrote:
If you have the 8535 gen IV series you have no thermocoupler. Mine did the exact same thing with the same code you are getting and it was the board.

Yes and no. Yes, there is no separate thermocouple. But, the ignitor serves that function (sensing temperature) for the PC board.

Here is an Atwood troubleshooting manual from 2003 O(need to verify it is the same as yours):
http://bryantrv.com/docs2/docs/hflamefurn04.pdf

On page 30:

BURNER IGNITES BUT IGNITION SYSTEM “LOCKS OUT” AND TURNS BURNER OFF
Low gas pressure
--------------------------------
Set pressure to a minimum of 11 ? W.C. with all appliances running.
Replace regulator if not obtainable.*
Exhaust blocked
----------------------------------
Clean exhaust.*
Combustion air wheel loose
------------------
Reposition wheel and tighten
Electrodes out of adjustment
------------------
Adjust electrode according to furnace specifications.
Electrode defective
------------------------------
Replace electrode.
Circuit Board defective
--------------------------
Clean plug contacts. If still defective, replace. (Check on board tester
when possible).
Flame sensor wire between electrode
------
Replace wire
and circuit board defective
Air leakage at gaskets
--------------------------
Replace gasket
Defective heat exchanger
----------------------
Replace heat exchanger

If you have the 8535 gen IV series you have no thermocoupler. Mine did the exact same thing with the same code you are getting and it was the board.

OK, let's go step by step.

We KNOW that the fan is running and that the sail switch is closing because the ignitor is sparking. That also means the gas valve SHOULD be opening.

Do you smell propane when you stand outside near the furnace when someone turns it on? If not, verify that propane is on at the tank. If so, do you hear/feel the propane solenoid "clicking" open?

If it tries to light-- i.e. you have BOTH spark and propane, but goes out, there is a problem with the thermocouple. The thermocouple's job is to tell the PC board that indeed there is a flame, so keep the gas flowing. Could be something as simple as a mud daubber's nest on the thermocouple, thermocouple not properly located, problem with wire from thermocouple to PC board or PC board problem.

Since it is under warranty, suggest it goes back to dealer.

Your fan should run for a few seconds prior to ignition to evacuate the chamber of gas. then it should openb the selenoid gas supply and try and spark. One of 2 things could be happening; either your fan is not running (part of the cycle) prior to ignition, or the selenoid to open the line to ignite is not opening. Once it's on it heats a thermocouple to sense flame to keep the selenoid open until the thermostate sends the signal to close. Any one of these parts could be failing or operating out of sync. resetting it could be resetting the cycle thus allowing only one cycle. That would be a board issue. That or your lines need blown out. Heck it could even be the furnace itself is heating a connection to the point of loosening, and then when it cools it closes enough to get current. In any case, if it's a warranty item, let them figure it out.

Check the inlet/exhaust for blockage
And unplug connector on board...clean contact area

Could be low propane pressure or faulty circuit board......both can be tested.
11" WC with other propane devices ON
Board tester....most any RV Repair Shop

Old-Biscuit wrote:
Check the combustion chamber inlet and exhaust ducting for any blockage....spider webs/nests/debris.
Also could be the spark electrode is dirty/out of alignment
And unplug connector on circuit board..clean contact area with a pencil eraser

When this happens........check for a red LED on circuit board......if flashing count the flashes and then check code chart for error (should be a notation on motor for codes)

The red light flashes three times (Ignition Lockout Fault)

Check the combustion chamber inlet and exhaust ducting for any blockage....spider webs/nests/debris.
Also could be the spark electrode is dirty/out of alignment
And unplug connector on circuit board..clean contact area with a pencil eraser

When this happens........check for a red LED on circuit board......if flashing count the flashes and then check code chart for error (should be a notation on motor for codes)