How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Michael Reush Your Own Question
Michael Reush
Michael Reush, RV Technician
Category: RV
Satisfied Customers: 3249
Experience:  Serving the rv industry since 1977
10974363
Type Your RV Question Here...
Michael Reush is online now
A new question is answered every 9 seconds

atwood 8531 furnace in my 2001 motor home ...circuit board

Customer Question

I have an Atwood 8531 furnace in my 2001 motorhome. Initial problem was the furnace was not igniting. I replaced the circuit board having deduced that the gas valva wa operating but no igniter spark. Not the board so I pulled the igniter assembly and checked the gap. I adjusted it so that there was a goot spark. reassembled and now the furnace runs and ignites properly buit the flame only stays "on" until the igniter stops. At least this is my assumption based upon the timing. The furnace tries for the three times before locking out with the same result. Any suggestions? Thanks Rod C
Submitted: 5 years ago.
Category: RV
Expert:  Michael Reush replied 5 years ago.

Michael Reush :

Thank you for using Just Answer, I will quickly, and methodicly work through your repair needs.......Thank you.........Michael

Michael Reush :

Hi, the igniter stricking and going off is a function of the circuit board,,,,,,,,Now dont get nervous I see where you have replaced it.........From your question I see you have been all through this heater, And I'll help you figure out what is next

Expert:  Michael Reush replied 5 years ago.
I am here waiting for your response............Michael
Customer: replied 5 years ago.
What more information do you need?
Expert:  Michael Reush replied 5 years ago.

Hi, the igniter stricking and going off is a function of the circuit board,,,,,,,,Now dont get nervous I see where you have replaced it.........From your question I see you have been all through this heater, And I'll help you figure out what is next

Customer: replied 5 years ago.

OK, I don't understand your response. I know the striker is controlled by the circuit board ( I have replaced it) and I expect the striker (ignitor) to go off . However, when the striker goes off the burner should remain on until the thermostat reaches set temp.

 

Where do I go from here?

Expert:  Michael Reush replied 5 years ago.
You are correct.....................Heres the deal that unit uses what they call local flame sensing, and the probe that is stricking when it heats up sends a signal back thru that wire, and says I"M LIT, and it will stay on..;If the signal doesnt come ( igniter wire shorting, flame not hot enough, probe bad ),,,,,,,,,,,,,,,,,,,,,,,,And yours is either not sending the signal,,,,,,,,,,,,,or the board is bad............Now again you have just replaced the board, so we can discoung #2..........
Expert:  Michael Reush replied 5 years ago.
And here is a link to the service manual, click here I think by now you probably have one, but I want to make sure so when we discuss it, were on the 'same page' so to speak..............Michael
Customer: replied 5 years ago.

Yes, I have a manual.

 

A couple of items that I don't understand. Looking at the wiring diagram in the manual I see 2 connections shown to the top of the circuit board, one is BLW and one is PWR. On my unit there are no such connections, just the plug which connects to ground, air and V1 plus the ignitor lead.

The other item is the ignitor has only two electrodes, one is grnd the other is HV (spark). How does the systmem sense the flame in order to keep the burner going once the ignition sequence is complete?

Expert:  Michael Reush replied 5 years ago.

directly back through the ignition lead

Customer: replied 5 years ago.
Thanks, XXXXX XXXXX I didn't deflect your problem solving.
Expert:  Michael Reush replied 5 years ago.
No your ok, its a human thing comunnicating with each other.......It takes a while in a conversation to 'get' the other person.........Both of us,,,,,,,,,,,,Please accept on this page, if your satisfied, we can talk afterwords and keep working if necessary.......Michael
Michael Reush and 2 other RV Specialists are ready to help you
Customer: replied 5 years ago.

As requested I have accepted your answer. How do we continue troubleshooting outside of the formal process?

Expert:  Michael Reush replied 5 years ago.
Right here .....................Michael
Expert:  Michael Reush replied 5 years ago.
I have to ride out to Phoinex , I'll be back later on tinite........MIchael
Expert:  Michael Reush replied 5 years ago.
Just wanted to say I got back a little late, I'll talk to you tomorrow........Michael