Atwood Heater Issue

[FishBamboo]

I'm having an issue with my Atwood forced air heater in my camper. 2015 model 8516-IV.
I turn on my heater and sometimes it works and sometimes it doesn't.
Sometimes it works then when it reaches set temperature it shuts off automatically like expected. Sometimes I shut it off, Either way 50% of the time the heater will not restart when needed. 50% it works fine. This is not a low voltage issue. Yes the propane is on. Replaced circuit board 2 weeks ago. Still the same issue. I have also bypassed the thermostat by removing it and touching the two wires together with no luck when this occurs. When it decides it wants to work touching the wires behind the thermostat together turns the heater on. So I don't think its the thermostat. Note the cool down cycle works fine. I have tried turning it on by the on/off switch and by the temperature setting lever. If it decides not to work I can leave the thermostat on in 20 to 30 degree temperature and hours later it sometimes starts working. A few nights ago it was in the 30's, I turned on the heater and then when the set temperature was reached it turn off like expected. Then the temperature inside the camper dropped and the heater would not go back on. I don't sleep with the heater on however I left it on and went to sleep. At about 04:00 it decided to work all by its self.

I need help as my girlfriend is not happy when we go without heat.

Any ideas?

Thanks in advance for your help.

 

[CougarCouple]

Good morning fishbamboo
You didn’t mention any of the gas side of the heater. Intermittent problem are difficult but not impossible to find. When the heater fails has it failed trying to light and going off on a safety? Or is it just dead in the water until it decided to start working? Check all electric plugs and all crimp connections.
Try having meter handy and when won’t work check voltage at battery then at the 12volt + and - ain’t the heater power input.

Russ

 

[Bigfoot Dave]

Had that happen a while ago. I could hear the sparker clicking on start up and sometimes it would light and sometimes not. Finally found that the ceramic around the base of the spark electrode was cracked right in the area where it was mounted in the metal mounting tab. It would short out but sounded like it was working fine. Replaced it and it has worked fine since. Hope this helps, Bigfoot Dave

 

[Stan@FourWheel]

When the furnace does not want to fire up again, are you hearing a "clicking" noise of the sparker trying to make ignition ?

Or just the furnace fan running only, with no short bursts of "clicking" ?


.

 

[FishBamboo]

Good morning fishbamboo
You didn’t mention any of the gas side of the heater. Intermittent problem are difficult but not impossible to find. When the heater fails has it failed trying to light and going off on a safety? Or is it just dead in the water until it decided to start working? Check all electric plugs and all crimp connections.
Try having meter handy and when won’t work check voltage at battery then at the 12volt + and - ain’t the heater power input.

Russ

All connections checked and tight. No clicks when turned on. Just dead in the water. Voltage checked. Have a solar charge controller read out showing me voltage and also checked with voltmeter. Whether its 13.5 or 12.3 it doesn't seem to matter.

Thanks

 

[FishBamboo]

Had that happen a while ago. I could hear the sparker clicking on start up and sometimes it would light and sometimes not. Finally found that the ceramic around the base of the spark electrode was cracked right in the area where it was mounted in the metal mounting tab. It would short out but sounded like it was working fine. Replaced it and it has worked fine since. Hope this helps, Bigfoot Dave

Bigfoot,

Spark Igniter seems to work fine.

Thanks

 

[FishBamboo]

When the furnace does not want to fire up again, are you hearing a "clicking" noise of the sparker trying to make ignition ?

Or just the furnace fan running only, with no short bursts of "clicking" ?


.

Stan,
When it decides not to work no igniter clicks, no fan nothing. Just dead in the water. Its a 50/50 chance whether I'm starting it for the 1st time on a trip or it has been running prior. Note the fan and heater work correctly when it decides to work.

All connections checked and tight. Voltage checked. Have a solar charge controller read out showing me voltage and also checked with voltmeter. Whether its 13.5 or 12.3 it doesn't seem to matter.

Thanks

 

[Old Crow]

Here's a Blower-Doesn't-Run portion of a troubleshooting checklist which I think applies to the 8516-IV...



Also-

- what thermostat are we talking about?

- what does the control-board LED show during yes-it-works vs now-it-doesn't runs? The LED is on the board so the outside cover has to be off to see it. I don't know if it will light at all but if it detects a problem it will flash or turn on with a solid color. There should be a sticker on the motor cover area showing what the flashing codes mean. They're a little cryptic but may give us a clue.

- you say you checked connections-- including the one to ground (I vaguely remember yellow wire going to a short ground bar tucked up under on right side. Does that make sense?)

- If I remember correctly the relay on my '01 8516-IV was obvious and looked like the one in the components-identification portion of the manual. And there's a test or bypass procedure for it. But I also remember reading something about the relay being moved or incorporated in the board so yours may not have an obvious one.
.

 

[CougarCouple]

Good evening
When the heater decides to not cooperate have you been able to verify voltage at the control module? If nothing is happening why, either the module does not know it needs to start or, the module can't go to step one. Try gently moving the wire going into the connection, sometimes pressing on the circut board will tell you something. Also check your ground circuit those can be problematic there is + voltage, but lack of ground or poor ground does not allow for a circuit. I know you said the module was replaced. Intermittent problems are very frustrating so sometimes going back to the basics helps.

If you keep looking you will find it. The fact it does nothing is good, it's a clue.

Russ

 

[FishBamboo]

Good evening
When the heater decides to not cooperate have you been able to verify voltage at the control module? If nothing is happening why, either the module does not know it needs to start or, the module can't go to step one. Try gently moving the wire going into the connection, sometimes pressing on the circut board will tell you something. Also check your ground circuit those can be problematic there is + voltage, but lack of ground or poor ground does not allow for a circuit. I know you said the module was replaced. Intermittent problems are very frustrating so sometimes going back to the basics helps.

If you keep looking you will find it. The fact it does nothing is good, it's a clue.

Russ

OK will do. Thanks again. Will post when I figure it out. Hopefully it will help someone else with the same issue someday.

 

[FishBamboo]

Here's a Blower-Doesn't-Run portion of a troubleshooting checklist which I think applies to the 8516-IV...

BlowerDoesntRunChecklist.jpg

Also-

- what thermostat are we talking about?

- what does the control-board LED show during yes-it-works vs now-it-doesn't runs? The LED is on the board so the outside cover has to be off to see it. I don't know if it will light at all but if it detects a problem it will flash or turn on with a solid color. There should be a sticker on the motor cover area showing what the flashing codes mean. They're a little cryptic but may give us a clue.

- you say you checked connections-- including the one to ground (I vaguely remember yellow wire going to a short ground bar tucked up under on right side. Does that make sense?)

- If I remember correctly the relay on my '01 8516-IV was obvious and looked like the one in the components-identification portion of the manual. And there's a test or bypass procedure for it. But I also remember reading something about the relay being moved or incorporated in the board so yours may not have an obvious one.
.

OK will check. Thanks for the help.