2017 - about ready to throw the heater in the garbage.

[Adventurebound]

I am so frustrated with this heater. Had issues since day one. Latest is no spark...again and this time it's pure magic..

- I've, replaced the sail switch, twice as I purchased a second (third) as a back up. No go. That was after doing the jumper wire instructions FWC has on their website that point to the sail switch as defective.

- Maybe it's the battery, low fan speed?, 12.7 volts, Victron shows 100%, start the truck up to add extra juice - no go.

- okay maybe trim the excess vent hose everyone is talking about...done...no go.

This is where it gets pure magical. If I remove the sail switch and manually trigger it, it fires up, well a few times it did. If I install the switch, use a peice of small wire to loop around the switch and manually trigger it, nothing!

What else am I missing?

Sorry for starting another "heater won't work" thread but I've read every single one of these over the year and still can't understand these heaters.

 

[camper rich]

What heater do you have?

 

[ri-f]

I am so frustrated with this heater. Had issues since day one. Latest is no spark...again and this time it's pure magic..

- I've, replaced the sail switch, twice as I purchased a second (third) as a back up. No go. That was after doing the jumper wire instructions FWC has on their website that point to the sail switch as defective.

- Maybe it's the battery, low fan speed?, 12.7 volts, Victron shows 100%, start the truck up to add extra juice - no go.

- okay maybe trim the excess vent hose everyone is talking about...done...no go.

This is where it gets pure magical. If I remove the sail switch and manually trigger it, it fires up, well a few times it did. If I install the switch, use a peice of small wire to loop around the switch and manually trigger it, nothing!

What else am I missing?

Sorry for starting another "heater won't work" thread but I've read every single one of these over the year and still can't understand these heaters.

It sounds like you've tried most of the tricks. Some heaters and stoves have a sensitive electrode gap that needs to be adjusted to get a consistent ignition spark, sort of like the gap on a spark plug. Your gap might be a little too narrow or too wide to spark consistently. I think I read somewhere that the gap on an Attwood/Dometic was about an 1/8 inch or possibly 1/4 inch. You might try looking at the service manual if you have one or search online for one to see what your heater model requires. Also the electrode's ceramic should be in good condition and not cracked. Just a thought. I've go a Wave 3 heater, a JetBoil stove, and an Attwood furnace, and they all have electrode gaps that need to be checked and adjusted if there is no spark. The Attwood could be more of a project, if that's what you're referring to. Not sure, you didn't mention the brand or model number. Good luck.

Rich

 

[JaSAn]

Voltage at the heater?
Voltage drop across the sail switch?

 

[kmcintyre]

Mother board? No spark but it fires up? I replaced all the inexpensive parts (jet, sail switch, etc.) until finally I replaced the board (with a Dinosaur (?) brand board) and no more issues but since yours is much newer, I can't believe it'd have problems that early but electronics can fail. I don't know how you'd test the board though w/o buying a new one unless the factory would send you one to "test".

 

[craig333]

It sounds like you've tried most of the tricks. Some heaters and stoves have a sensitive electrode gap that needs to be adjusted to get a consistent ignition spark, sort of like the gap on a spark plug. Your gap might be a little too narrow or too wide to spark consistently. I think I read somewhere that the gap on an Attwood/Dometic was about an 1/8 inch or possibly 1/4 inch. You might try looking at the service manual if you have one or search online for one to see what your heater model requires. Also the electrode's ceramic should be in good condition and not cracked. Just a thought. I've go a Wave 3 heater, a JetBoil stove, and an Attwood furnace, and they all have electrode gaps that need to be checked and adjusted if there is no spark. The Attwood could be more of a project, if that's what you're referring to. Not sure, you didn't mention the brand or model number. Good luck.

Rich

I had to adjust the spark gap on mine and its work flawlessly ever since. Its a suburban though.

 

[Adventurebound]

Thanks for the replies all. It's a 2017 model that came with the Dometic, model number AFSAD12111.

 

[ri-f]

Thanks for the replies all. It's a 2017 model that came with the Dometic, model number AFSAD12111.

https://youtu.be/AB69oqtSiwc

Look at this clip, it relates to the electrode gap I mentioned previously.

Rich

 

[CougarCouple]

Hello adventurebound

If it’s that intermittent, I would be looking for an electrical issue. Poor crimp. Bad or cold solder joint. How does it prove flame. Might be a poor ground, loose or dirty
Back to circuit board.
Do you have a meter to verify proper voltage at the board. Does voltage drop when unit starts to try light.
Good luck

 

[patrkbukly]

I am so frustrated with this heater. Had issues since day one. Latest is no spark...again and this time it's pure magic..

- I've, replaced the sail switch, twice as I purchased a second (third) as a back up. No go. That was after doing the jumper wire instructions FWC has on their website that point to the sail switch as defective.

- Maybe it's the battery, low fan speed?, 12.7 volts, Victron shows 100%, start the truck up to add extra juice - no go.

- okay maybe trim the excess vent hose everyone is talking about...done...no go.

This is where it gets pure magical. If I remove the sail switch and manually trigger it, it fires up, well a few times it did. If I install the switch, use a peice of small wire to loop around the switch and manually trigger it, nothing!

What else am I missing?

Sorry for starting another "heater won't work" thread but I've read every single one of these over the year and still can't understand these heaters

Is it not coming on at all altitudes?
Yes get a Dinasour board.
Yes pull the ignitor and verify spark and distance of the ends of the ignitor. For me living at 10,000 feet, adding another 1/8" helped/solved the unreliability.
Have you checked the reset switch?

Stan is awesome, maybe reach out to him.

 

[Stan@FourWheel]

Newest Furnace Troubleshooting Video:

https://vimeo.com/533706023

 

[Adventurebound]

Appreciate all the replies and the video...however I have come to the conclusion I have the wrong style furnace in my camper from the factory. Let me tell you why:

The sail switch on my model furnace sits vertical. All the video and trouble shooting videos I have seen sit horizontal. Why does that make a difference? The momentum of gravity and the force of the blower is not enough to push the switch up and close the contacts. This style furnace I believe is only to be mounted horizontal, thus keeping the sail switch horizontal. As you know furnaces in FWC are mounted vertical.

How did I come to this conclusion? Blower speed appears to be fine, 14.5 volts at the motor when running. I can manualy take a wire and close the sail switch circuit while running and it fires up, conversely when running If I stick an ohms meter across the sail switch the circuit never closes, thus not enough force of air to push the switch UP and close the circuit. Again 14.5 volts at the blower.

Since this didn't just start happening I'm thinking this has been the issue all along. It would be interesting to know how many others have thus style switch. Camper is a 2017 but blower motor says manufacturered in 2015.

 

[Adventurebound]

Photo

As you can see at the top of the switch is the blade that stands vertical.

 

[Casa Escarlata Robles Too]

That is very interesting.Makes sense though.
Did you buy the camper new?

At least now you have what looks like a good starting point.
Frank

 

[Adventurebound]

Original owner purchased new from the factory.

 

[CougarCouple]

Good job troubleshooting. Could the sails switch have been installed improperly?
Does the manufacture have multiple furnace for different applications?
Thanks for the posting on your progress.
Russ

 

[Adventurebound]

Yes Couger Couple I had also meant to put that in the post. I learned the hard way that they have two different style sail switches for this model furnace. I kept ordering new ones only to receive an
"Incorrect" switch. That's when I came to learn that there are two styles of sail switches for this model number depending on the serial number. AFSAD12111. One for serial numbers lower than 72498929 and one for serial numbers above that.

The white one is the one I see being replaced in all the posts online and looks like it's housed in the lower blower motor horizontally.

The black straight blade is the correct one for my serial number. It's mounted in the upper blower motor vertically.

I could be wrong on all this but man I'm just not seeing anything else it could be?

Oh and here is a link to the service manual. I've spent hours and hours chasing wires and trouble shooting this.

http://techsupport.pdxrvwholesale.com/wp-content/uploads/2018/10/Atwood-Mobile_Service-Training-Manual-2015.pdf

 

[ri-f]

Yes Couger Couple I had also meant to put that in the post. I learned the hard way that they have two different style sail switches for this model furnace. I kept ordering new ones only to receive an
"Incorrect" switch. That's when I came to learn that there are two styles of sail switches for this model number depending on the serial number. AFSAD12111. One for serial numbers lower than 72498929 and one for serial numbers above that.

The white one is the one I see being replaced in all the posts online and looks like it's housed in the lower blower motor horizontally.

The black straight blade is the correct one for my serial number. It's mounted in the upper blower motor vertically.

I could be wrong on all this but man I'm just not seeing anything else it could be?

Oh and here is a link to the service manual. I've spent hours and hours chasing wires and trouble shooting this.

http://techsupport.pdxrvwholesale.com/wp-content/uploads/2018/10/Atwood-Mobile_Service-Training-Manual-2015.pdf

Adventurebound, thank you, for posting the service manual link. That is very helpful and valuable info. You are right, it is very difficult to find the service manual for free. And great detctive work on the sail switch.

Rich

 

[Old Crow]

A few thoughts---

- The manual says the furnace can be installed either horizontally or vertically. (Page 5, Heat Outlets paragraph).

- The furnace has an LED on the control board. The codes it flashes should be on shown on a label you can see with the cover removed. You might watch that LED both when the furnace seems to be operating ok and when it's not. What does it indicate?

- This may be a long shot but there was a Service Bulletin for the limit switch on all AFS models in a certain serial number range. I see language in there about the sail switch becoming inoperative due to the limit switch wiring grounding out. Seems unlikely it would be an intermittent problem but who knows. You might read through to see what you think.

- Given what I've read thus far I think I'd try making the sail-switch paddle bigger with a piece of tape or label (something I could easily remove) to see if it makes a difference.

- Air flow is very important. I assume you've checked thoroughly for something like dog hair, a piece of plastic bag, etc impeding flow or making it more turbulent (I know it's not easy to check thoroughly). The other thought is a possible missing duct plate (the punch-outs in the case for unused duct outlets) causing airflow problems)

.

 

[Adventurebound]

A few thoughts---

- The manual says the furnace can be installed either horizontally or vertically. (Page 5, Heat Outlets paragraph). I don't disagree there. But could have Dometic made a mistake with the design? After all they did change the location and position of the sail switch in the newer serial number furnaces. Also to be clear, I am not bagging on FWC. The camper itself has been fantastic, its just all this Dometic stuff they are pretty much forced to use.

- The furnace has an LED on the control board. The codes it flashes should be on shown on a label you can see with the cover removed. You might watch that LED both when the furnace seems to be operating ok and when it's not. What does it indicate? I get the one flash 3 second pause - limit switch (sail switch fault)

- This may be a long shot but there was a Service Bulletin for the limit switch on all AFS models in a certain serial number range. I see language in there about the sail switch becoming inoperative due to the limit switch wiring grounding out. Seems unlikely it would be an intermittent problem but who knows. You might read through to see what you think. Not a long shot. Thanks for attaching that. My furnace falls in that serial number range. I will check on this. Although I don't think that would inhibit the sail switch manually operating?

- Given what I've read thus far I think I'd try making the sail-switch paddle bigger with a piece of tape or label (something I could easily remove) to see if it makes a difference. I was thinking the same thing last night...

- Air flow is very important. I assume you've checked thoroughly for something like dog hair, a piece of plastic bag, etc impeding flow or making it more turbulent (I know it's not easy to check thoroughly). The other thought is a possible missing duct plate (the punch-outs in the case for unused duct outlets) causing airflow problems) I did check this. I also blew out the motor and fan with compressed air. While I was at it I used the compressor to spin the fan at a much higher speed than I assumed the motor would turn it and the switch did not close either.

.