Atwood Furnace Fast Flashing Light

[chuckster57]

It senses that there is a flame to keep the gas valve open.

[jasin1]

oftentimes you can clean a flame sensor to get it working again…sometimes indefinitely and sometimes for a couple of days..you can use really fine emory cloth…i keep a 3” piece of emory that i’ve used for cleaning copper fittings that’s almost completely worn away…you can take a piece and start sanding a old piece of steel or anything to get most of the abrasive off…you don’t want to rough up the metal on the flame sensor too much as it will attract dirt that will just make the sensor fail again…just give the sensor a couple of twists with the emory…you can even use the back of the emory

check the wire connectors on the flame sensor also and make sure they are clean and snug

check the orientation to the flame of the sensor..sometimes the sensor is not positioned into the flame…wind can affect it also


the sensor reads micro amps generated by the flame and sends the signal back to the board.

here’s an article..i’ve been cleaning flame sensors for 35 years and it works most of the time


another thing to consider is the actual size and characteristic of the flame..if it doesn’t hit the flame sensor correctly it won’t read the flame…i dirty pilot/ burner will cause the flame to burn yellowish and not hot enough…a little piece of 1/4 “ hose that you can blow thru sometimes clears the head up….also the gas pressure can affect the flame characteristics so verify your getting the right pressure.
all that’s happening now is the board doesn’t see the the correct amperage back could be one of a couple things…https://www.deppmann.com/blog/servic...flame-sensors/

[jsb5717]

Thanks, guys. I do have a new electrode so I'll get after it again this afternoon and let you know.

[jsb5717]

Well...no dice. New electrode/flame sensor but it's still igniting and turning back off. There's nothing else to replace so not sure what it could be unless it's bad propane or something in the line. Those seem like very remote possibilities to me but not sure where else to look.

[jasin1]

Originally Posted by jsb5717

Well...no dice. New electrode/flame sensor but it's still igniting and turning back off. There's nothing else to replace so not sure what it could be unless it's bad propane or something in the line. Those seem like very remote possibilities to me but not sure where else to look.

check gas pressure with a manometer at the furnace valve..could be debris against the screen at the gas valve inlet …low gas pressure when the valve opens the pressure drops so much so quickly it just shuts down ..can’t keep the burners lit…id also check for a good solid clean ground connection at the board and controls…try running a second ground from the battery area temporarily to see if it helps

a weird phenomenon also happens when water gets in a gas line…the pressure when the burner comes on pushes the water up and stifles the pressure…shuts off ..then it recedes and the process can happen again

[jsb5717]

Don't have a manometer but we've tried with 2 new propane regulators. We just put a new one in my buddy's rig and I bought one as a backup. We did discuss blowing out the propane line so maybe that's next just to check for debris or water. The cooktop seems to work just fine with good pressure but it doesn't have nearly the same requirement for gas pressure.

Thanks for the ideas. Will get back with results.

[jasin1]

you said it worked perfectly on the bench then when you reinstalled it it wouldn’t work until you found a wire issue? then it worked for a short while before acting up again? …i’m leaning towards a voltage or wiring issue but also does the flame go out right about the time that the blower kicks on ?…blower motor maybe drawing high amps and your losing power for the gas valve…12 volt furnaces aren’t my forte but just trying to read all the clues.

also are you certain you have a good blue flame surrounding the flame sensor when the pilot ignites?…dirty pilot burners are a very common problem on both thermocouple and flame sensor gas systems

[jsb5717]

I love good troubleshooting kind of thinking. I don't think that's the issue, though. The last hullaballoo turned out to be nothing more that a bad 12v supply wire. Once rewired to a sound connection it worked perfectly. But...never say never, right? Next trip over there I will also check the power supply.

Also, I can't ever see the flame when it ignites since it's all enclosed. And with the new propane valve and burner/diffuser there's no dirt or buildup anywhere to get in the way.

This time the trouble started just after having both tanks refilled but ran perfectly before. The idea of potential moisture in the line makes some sense so we will blow out the line and see. That won't be until tomorrow afternoon at this point but will definitely let you know how it shakes out.

[jasin1]

Originally Posted by jsb5717

I love good troubleshooting kind of thinking. I don't think that's the issue, though. The last hullaballoo turned out to be nothing more that a bad 12v supply wire. Once rewired to a sound connection it worked perfectly. But...never say never, right? Next trip over there I will also check the power supply.

Also, I can't ever see the flame when it ignites since it's all enclosed. And with the new propane valve and burner/diffuser there's no dirt or buildup anywhere to get in the way.

This time the trouble started just after having both tanks refilled but ran perfectly before. The idea of potential moisture in the line makes some sense so we will blow out the line and see. That won't be until tomorrow afternoon at this point but will definitely let you know how it shakes out.

sounds good …look into the gas valve inlet connection as well ..most but not all gas valves have a inlet screen to prevent debris from getting into the gas valve and causing it to stick open..could be something like a piece of teflon tape against it..and then check all the wire connectors for corrosion if you didn’t already do that…can’t remember that far back into the thread..good luck

[chuckster57]

If it’s a gas valve issue, it would be an obstruction because the flame goes out right away. At this point I would start bench testing.

[CampNBrew2]

This is all good sleuthing by everyone. Love it!

One thing that catches my eye is that you had the tanks filled. This means they were disconnected, pressure bled and air was introduced to the system.

My question is how many times did you try to light the furnace before making these conclusions? Are you sure all air was purged from the lines after you reconnected the tanks? My normal procedure after a disconnect is to turn on all stove burner gas valves until I start to smell gas then light them and make sure they're burning clean. My furnace and fridge are downstream of the stove so they get a burner check also.

Something else to ponder. Hopefully it is something this easy and you're not chasing your tail.

Good work so far

[jsb5717]

Originally Posted by CampNBrew2

This is all good sleuthing by everyone. Love it!

One thing that catches my eye is that you had the tanks filled. This means they were disconnected, pressure bled and air was introduced to the system.

My question is how many times did you try to light the furnace before making these conclusions? Are you sure all air was purged from the lines after you reconnected the tanks? My normal procedure after a disconnect is to turn on all stove burner gas valves until I start to smell gas then light them and make sure they're burning clean. My furnace and fridge are downstream of the stove so they get a burner check also.

Something else to ponder. Hopefully it is something this easy and you're not chasing your tail.

Good work so far

More good thoughts, but yes, we did think of that. Furnace is right beside cooktop. We made sure we had good, strong flames on the burners before trying the furnace. Then we'd let it try several times just in case there was air in the line.

[jsb5717]

Originally Posted by chuckster57

If it’s a gas valve issue, it would be an obstruction because the flame goes out right away. At this point I would start bench testing.

That's where I am as well. Bummer is that we are taking off today for a month so my buddy will have no furnace to start our trip. When we get to our first park for 3 nights we'll take some time to check the regulator for blockage and blow out the line. If that doesn't fix anything it'll have to wait until we get back. For a couple weeks we're all in AZ (Tucson and Phoenix) so warmer, drier weather...looking forward to that!

[jsb5717]

So last night all we did was swap out one of the newly filled bottles with a spare bottle that I have and the furnace started right up. Not sure why the newly filled bottles won’t fire the furnace but that’s where we are.

We are currently camping in central Oregon with 25 deg night time temps. I’ll check in with him in a little bit to see how it went over night.

If more develops on this issue I’ll continue to report back. I really appreciate the input and suggestions. I’m a pretty handy guy and can usually figure out most RV and home problems for mechanical, plumbing, electrical, etc. But I can also get stumped…like this time. I sometimes say:

I know a little about a lot
I know a lot about a little
I know nothing about some
And I know everything about nothing

There’s always space to learn something new and I love it when that happens. I continue to learn great tidbits just reading this forum. Thanks again for the help. I’ll let you know how it goes.

[jasin1]

Originally Posted by jsb5717

So last night all we did was swap out one of the newly filled bottles with a spare bottle that I have and the furnace started right up. Not sure why the newly filled bottles won’t fire the furnace but that’s where we are.

We are currently camping in central Oregon with 25 deg night time temps. I’ll check in with him in a little bit to see how it went over night.

If more develops on this issue I’ll continue to report back. I really appreciate the input and suggestions. I’m a pretty handy guy and can usually figure out most RV and home problems for mechanical, plumbing, electrical, etc. But I can also get stumped…like this time. I sometimes say:

I know a little about a lot
I know a lot about a little
I know nothing about some
And I know everything about nothing

There’s always space to learn something new and I love it when that happens. I continue to learn great tidbits just reading this forum. Thanks again for the help. I’ll let you know how it goes.

Could be a bad valve on the propane tank not allowing full pressure to regulator. Or it was opened too fast and locked up the regulator…just be sure you open the tank slowly

[sourdough]

Originally Posted by jsb5717

So last night all we did was swap out one of the newly filled bottles with a spare bottle that I have and the furnace started right up. Not sure why the newly filled bottles won’t fire the furnace but that’s where we are.

We are currently camping in central Oregon with 25 deg night time temps. I’ll check in with him in a little bit to see how it went over night.

If more develops on this issue I’ll continue to report back. I really appreciate the input and suggestions. I’m a pretty handy guy and can usually figure out most RV and home problems for mechanical, plumbing, electrical, etc. But I can also get stumped…like this time. I sometimes say:

I know a little about a lot
I know a lot about a little
I know nothing about some
And I know everything about nothing

There’s always space to learn something new and I love it when that happens. I continue to learn great tidbits just reading this forum. Thanks again for the help. I’ll let you know how it goes.

Jeff I have had that happen to me. Sorry I just didn't remember until you posted. I ended up with a new bottle. Mine apparently just wouldn't put out enough flow and I was too lazy to try to fix it. It did however cause me great irritation. Glad you found it.

[jsb5717]

Thanks, all. So…to continue. After consulting with a couple different propane industry pros the furnace is now working with their original bottles. Turns out my buddy has been in the habit of opening them too quickly and this time it bit him. We were told that in that scenario that if the ball valve gets jammed that it’s also possible for the valve to self correct after sitting for some time. We figured we had nothing to lose so we connected first one, then the other bottle in his 5er and both are now running the furnace. He’s learned his lesson and so have I…

Before replacing every part in the furnace (which I already had on hand as backup for any furnace issue) make sure the bottle is working correctly. Assume nothing. Sigh…live and learn.

[Kirk's Keystone Outback.]

Originally Posted by jsb5717

Thanks, all. So…to continue. After consulting with a couple different propane industry pros the furnace is now working with their original bottles. Turns out my buddy has been in the habit of opening them too quickly and this time it bit him. We were told that in that scenario that if the ball valve gets jammed that it’s also possible for the valve to self correct after sitting for some time. We figured we had nothing to lose so we connected first one, then the other bottle in his 5er and both are now running the furnace. He’s learned his lesson and so have I…

Before replacing every part in the furnace (which I already had on hand as backup for any furnace issue) make sure the bottle is working correctly. Assume nothing. Sigh…live and learn.

Thanks for sharing the end result. It's definitely a reminder for myself, at least.

[chuckster57]

And now you want to kick someone in the backside. Funny how this wasn’t brought up in any reply (including mine) as I’m sure we ALL figured he know how to turn the propane on.

[jasin1]

Originally Posted by chuckster57

And now you want to kick someone in the backside. Funny how this wasn’t brought up in any reply (including mine) as I’m sure we ALL figured he know how to turn the propane on.

(coughs)….see post #35