Water Heater will not stay lit with door closed

[peekay17]

Hello,

I have a Dometic WH-6GEA water heater on my Coachmen Apex Nano trailer. It does not work properly with the door closed, however, if I open the door/panel it works properly. There is no way to adjust the flame on this model to allow more oxygen into the mixture. I have attached a video of what happens. Eventually, if I let it run with the door closed, it will error out and need to be turned off and back on to start functioning again. If I leave the door open, it works fine. I've blown out the burner tube, but that doesn't seem to resolve the issue.

Here is a link to a video demonstrating the issue. Any thoughts? Any help is much appreciated!

https://share.icloud.com/photos/0bcf...VV70xYZya3ZAiQ

Thanks.

[stephndudb]

Did it work normally before? Was it stored for the winter?

[peekay17]

It has never worked properly in the 3 years since I bought it new. Brought it to the dealer and they stated it was because the tube was dirty, but that's not the case. Thanks.

[Larry-NC]

See if this helps:

https://www.youtube.com/watch?v=CTPGYuNPz6I

[peekay17]

Thank you Larry. Unfortunately, I don't believe this video speaks to the issue I am having as it does ignite and will do so routinely, just has the flame out issue with the door open. I will check the igniter wire and spacing to be sure, but I'm not sure that accounts for the oxygen issue.

[Custmachr]

Originally Posted by peekay17

Hello,

I have a Dometic WH-6GEA water heater on my Coachmen Apex Nano trailer. It does not work properly with the door closed, however, if I open the door/panel it works properly. There is no way to adjust the flame on this model to allow more oxygen into the mixture. I have attached a video of what happens. Eventually, if I let it run with the door closed, it will error out and need to be turned off and back on to start functioning again. If I leave the door open, it works fine. I've blown out the burner tube, but that doesn't seem to resolve the issue.

Here is a link to a video demonstrating the issue. Any thoughts? Any help is much appreciated!

https://share.icloud.com/photos/0bcf...VV70xYZya3ZAiQ

Thanks.

Please see pages 9-10

[peekay17]

Originally Posted by Custmachr

Please see pages 9-10

Thanks, but this is for a different water heater. This is for an Atwood and mine is a Dometic. There is no "Air shutter" on a Dometic model.

[wmtire]

Originally Posted by peekay17

Thanks, but this is for a different water heater. This is for an Atwood and mine is a Dometic. There is no "Air shutter" on a Dometic model.

FYI, Dometic is the new name for the older Atwood water heaters (company change). Although some Dometics do not have the air shutter, some Dometic do/did.

See page 5 here under preventive maintenance for Dometic water heaters:

https://www.dometic.com/externalasse...tric_64489.pdf

Yours indeed may not have an air shutter. Is there anyway you can possibly take a pic of your water heater with the cover open, and post it in this thread? Thanks

[Larry-NC]

Originally Posted by peekay17

Thank you Larry. Unfortunately, I don't believe this video speaks to the issue I am having as it does ignite and will do so routinely, just has the flame out issue with the door open. I will check the igniter wire and spacing to be sure, but I'm not sure that accounts for the oxygen issue.

If it lights, the igniter wire is okay. Sorry I can't suggest more, but I'm only familiar with Suburban water heaters.

[TitanMike]

After watching the video two thoughts come to mind:


*The flame is being "smothered" by lack of fresh air entering at the bottom of the unit and combustion gases filling the upper portion of the burner compartment. A major portion of combustion gases from a propane flame is CO2 which is heavier than air and will smother a flame as it displaces oxygen. Is the cover tight against the exhaust? If so, where does combustion air get in?

This may account for the heater working fine with the door open.


*a variation of the above, the flame may not be hitting the thermocouple that keeps the gas solenoid open. Door closed alters the amount of flame impinging on the thermocouple. Check it's position and see if it's support is possibly bent. Does it look like it would be well heated by the flame?




If this were my unit I'd be looking carefully to see where air is entering the compartment with the door closed. Logically it will come from the bottom with plenty of hot gas venting ability at the top of the door. Since door position seems to be the only factor that's where I'd focus.

As I said, just some thoughts.

[peekay17]

Originally Posted by wmtire

FYI, Dometic is the new name for the older Atwood water heaters (company change). Although some Dometics do not have the air shutter, some Dometic do/did.

See page 5 here under preventive maintenance for Dometic water heaters:

https://www.dometic.com/externalasse...tric_64489.pdf

Yours indeed may not have an air shutter. Is there anyway you can possibly take a pic of your water heater with the cover open, and post it in this thread? Thanks

Thanks for that info. Here's a link to the same water heater I have, I don't have a picture right now, apologies.

https://worldofrvparts.com/ols/produ...ectric-wh-6gea

[peekay17]

Originally Posted by TitanMike

After watching the video two thoughts come to mind:


*The flame is being "smothered" by lack of fresh air entering at the bottom of the unit and combustion gases filling the upper portion of the burner compartment. A major portion of combustion gases from a propane flame is CO2 which is heavier than air and will smother a flame as it displaces oxygen. Is the cover tight against the exhaust? If so, where does combustion air get in?

This may account for the heater working fine with the door open.


*a variation of the above, the flame may not be hitting the thermocouple that keeps the gas solenoid open. Door closed alters the amount of flame impinging on the thermocouple. Check it's position and see if it's support is possibly bent. Does it look like it would be well heated by the flame?




If this were my unit I'd be looking carefully to see where air is entering the compartment with the door closed. Logically it will come from the bottom with plenty of hot gas venting ability at the top of the door. Since door position seems to be the only factor that's where I'd focus.

As I said, just some thoughts.

Appreciate the thoughts! As far as I can tell, the door fits properly and the intake should be from the top. From what I can tell, the flame is properly hitting the thermocouple when the door is closed, but of course, that's hard to see .

Here's another thread from a winnebago forum where the person had the same issue...

https://www.winnieowners.com/forums/...en-363753.html

[GolfingDave]

I see you are in Colorado. How high?

This is out of my Suburban Water Heater Manual though. Coiuld be a factor?

HIGH ALTITUDE DERATION
Suburban water heaters are certified by nationally recognized testing laboratories for
operation without modifications at altitudes up to 4,500 feet. Operation above this
elevation may require derating by 4 percent for every 1,000 feet above sea level. For
example, at 8,000 feet, the water heater should be derated approximately 32 percent.
If the unit is not properly derated, lack of sufficient oxygen for combustion may produce
improper burner operation. Pilot outage caused by burner lift-off or sooting from a yellow
burner may occur indicating the possibility of carbon monoxide. You may also notice a
lack of efficiency in heating the water because of incomplete combustion of the burner
at these higher altitudes.
Consult with the local gas company, your dealer, an RV service agency or Suburban
Manufacturing Company for proper derating of the unit. Change-out of the orifice
(derating) should be done by the dealer or a qualified service agency.
NOTE: It is important that once the unit has returned to lower elevation (below 4,500
feet), this high altitude deration and pilot adjustments (if equipped) be reversed for
proper operation of the unit.

[Custmachr]

Originally Posted by peekay17

Thanks, but this is for a different water heater. This is for an Atwood and mine is a Dometic. There is no "Air shutter" on a Dometic model.

Atwood and Dometic are the same company but your must be a newer model. I assume that if it is not burning correctly then maybe the gas pressure is not correct.

[peekay17]

Originally Posted by GolfingDave

I see you are in Colorado. How high?

This is out of my Suburban Water Heater Manual though. Coiuld be a factor?

HIGH ALTITUDE DERATION
Suburban water heaters are certified by nationally recognized testing laboratories for
operation without modifications at altitudes up to 4,500 feet. Operation above this
elevation may require derating by 4 percent for every 1,000 feet above sea level. For
example, at 8,000 feet, the water heater should be derated approximately 32 percent.
If the unit is not properly derated, lack of sufficient oxygen for combustion may produce
improper burner operation. Pilot outage caused by burner lift-off or sooting from a yellow
burner may occur indicating the possibility of carbon monoxide. You may also notice a
lack of efficiency in heating the water because of incomplete combustion of the burner
at these higher altitudes.
Consult with the local gas company, your dealer, an RV service agency or Suburban
Manufacturing Company for proper derating of the unit. Change-out of the orifice
(derating) should be done by the dealer or a qualified service agency.
NOTE: It is important that once the unit has returned to lower elevation (below 4,500
feet), this high altitude deration and pilot adjustments (if equipped) be reversed for
proper operation of the unit.

It's a good question, one that I've thought of myself! I don't believe there is a way to derate this WH, but I've reached out to Dometic for their input as well. This issue presents either at 4,000 ft. or 9,000 ft. I see many postings about this issue on the internet, but no one seems to post a resolution .

[GolfingDave]

Originally Posted by peekay17

It's a good question, one that I've thought of myself! I don't believe there is a way to derate this WH, but I've reached out to Dometic for their input as well. This issue presents either at 4,000 ft. or 9,000 ft. I see many postings about this issue on the internet, but no one seems to post a resolution .

What I saw that was odd was the blue poof of flame when it reignites. Out of curiosity I would want to watch what happens on initial start up when the heat kicks on. Have someone turn the temp up on the thermostat while watching. See if it has a poof on initial start up. If not then that must be from residual gas.

Even if no one comes up with derating it, I would bet that the orifice is a standard size. Find out what Suburban uses for a derated orifice and maybe swap it out and watch what happens. It is going to be a smaller orifice(verify by size stamped on it) so should not cause any harm. Check the btu's of a Suburban against yours. If the same you can try it. See what number is stamped on your orifice. Do not go bigger orifice, only smaller.

Here is a link to a chart to give you and idea of the btu by orifice size. Lower number means more btu output.

https://www.johnstonesupply.com/orifice-chart

Warning: Only do what you are comfortable with.

[TitanMike]

Since he unit operates fine with door open how would any "de-rating" steps make a difference?

If the vent was covered with soot maybe so.

[GolfingDave]

Originally Posted by TitanMike

Since he unit operates fine with door open how would any "de-rating" steps make a difference?

If the vent was covered with soot maybe so.

Was just posting what Suburban is saying in their manual posted above. Even though it is a Dometic. A lot of "mays" in their reasoning.

"If the unit is not properly derated, lack of sufficient oxygen for combustion may produce
improper burner operation. Pilot outage caused by burner lift-off or sooting from a yellow
burner may occur indicating the possibility of carbon monoxide. You may also notice a
lack of efficiency in heating the water because of incomplete combustion of the burner
at these higher altitudes."

Not saying that is the problem but I have worked on enough things to know sometimes you just have to try different approaches and see what happens.

Just wanted to post it for an option or something to think about.

"how would any "de-rating" steps make a difference?"
Less air able to enter with the door closed possibly which means less oxygen. Smaller orifice might be sufficient to sustain combustion. Notice I said might.

[TitanMike]

Originally Posted by GolfingDave

Was just posting what Suburban is saying in their manual posted above. Even though it is a Dometic. A lot of "mays" in their reasoning.

"If the unit is not properly derated, lack of sufficient oxygen for combustion may produce
improper burner operation. Pilot outage caused by burner lift-off or sooting from a yellow
burner may occur indicating the possibility of carbon monoxide. You may also notice a
lack of efficiency in heating the water because of incomplete combustion of the burner
at these higher altitudes."

Not saying that is the problem but I have worked on enough things to know sometimes you just have to try different approaches and see what happens.

Just wanted to post it for an option or something to think about.

"how would any "de-rating" steps make a difference?"
Less air able to enter with the door closed possibly which means less oxygen. Smaller orifice might be sufficient to sustain combustion. Notice I said might.

Again, if at altitude the amount of oxygen is naturally less but it will be the same if door is open or closed.

Have you read the link to same heater heater issue in a Winnebago? It appears that Winnebago's fix was to remove some butyl seal material that was inhibiting air glow at bottom of heater where burner tube would draw air.

Remember, unless there is a blower units like this rely on convection with hot air rising and cold air filling in from the bottom.


FWIW, Watching the video of the dying flame looks a lot like back in my High School science lab where a candle was lit then covered with an inverted beaker. As oxygen was consumed the flame would die almost exactly the same way.

[GolfingDave]

Again, if at altitude the amount of oxygen is naturally less but it will be the same if door is open or closed. Percentage wise oxygen to nitrogen to carbon dioxide but not volume wise. A 12x12 inch door open is going to let in a lot more volume than that small opening shown in the video. I do not see any openings at the bottom or side, could be there but I do not see them. Maybe a manufacturing error? On my camper the openings for intake and exhaust are side by side. Air flow circulates counterclockwise once past the door. Caveat: I do not recall if percentages stay the same at altitude, I must have not been paying attention that day at school. But regardless flow volume has to go down.

Have you read the link to same heater heater issue in a Winnebago? It appears that Winnebago's fix was to remove some butyl seal material that was inhibiting air glow at bottom of heater where burner tube would draw air. Yes and that is an option for him to try. Same as mine, just an option out there. What works for one manufacturer may or may not work with another manufacturer's product.

Remember, unless there is a blower units like this rely on convection with hot air rising and cold air filling in from the bottom. Agree, and that is why mine has two openings with a shield to force inlet air down.