water heater anomaly

az wiz · 12-28-2021, 11:35 AM

Has anyone had an issue with the water heater? Mine runs fine on propane with the door of water heater open, when I close the water heater door it goes out.

2022 2108DS Micro Minnie

DavidM · 12-28-2021, 12:29 PM

Sounds like you may have a blocked vent somewhere. With the door closed the WH's burner doesn't get enough air and it goes out.

David

**creativepart** · 12-28-2021, 01:27 PM

Try adjusting the burner flu tube:

https://www.youtube.com/watch?v=AFkS5n1dF7U

Morich · 12-28-2021, 02:02 PM

While there it is always good to think about how the openings on the water heater and furnace may need screens to keep bugs out. It takes a small bit to screen mud daubers out and lots to find and clean them out after they stop up the air flow on things!
When airflow becomes a question, take a minute to look for something like a wasp nest built in the space where air should flow.
They seem to love those tight little spaces for building a great big old nest!

TenorBob53 · 01-02-2022, 06:27 PM

I just recently had this problem but it was with the igniter. The unit would fire up fine with the access door open but not when closed. I found that the propane igniter wire was shorting out to the door when closed. I just made sure the wire was "tucked down" away from the door when closed. It's been working fine ever since.
Good luck.
Bob
2007 Journey 36G

az wiz · 01-04-2022, 06:44 AM

Quote:

Originally Posted by TenorBob53

I just recently had this problem but it was with the igniter. The unit would fire up fine with the access door open but not when closed. I found that the propane igniter wire was shorting out to the door when closed. I just made sure the wire was "tucked down" away from the door when closed. It's been working fine ever since.
Good luck.
Bob
2007 Journey 36G

Thanks will try that, you must have a new version wh also as there is no air to fuel adjustment

Morich · 01-04-2022, 07:46 AM

I might first ask a couple questions as I see some things I don't understand?
Does this heater have screens to keep bugs out? That is one first thought when fire starts but then stops as the bugs love to get int these small spaces and build nests like in the airflow, so if no screen, I might jump straight to cleaning the airflow and putting screens on to stop the next time!
But I also see what looks like strange color on the air tube. Is it actuall blue like flame is burning in the tube rather than insdie the heater?

That woud tell me for sure there is an air restriction not letting the gas go insdie before igniting!
Is there something odd in three of the vents or just something I'm not used to seeing?

Maybe a check of this manual would be a good guide?

https://epi.dometic.com/externalasse...4379_81175.pdf

**creativepart** · 01-04-2022, 08:09 AM

Quote:

Originally Posted by az wiz

Thanks will try that, you must have a new version wh also as there is no air to fuel adjustment

Oh, you have a different brand WH than most Winnebago RVs. The most common are Atwood and Suburban. Yours is a Dometic. Sorry, Winnebago is changing things up. I assumed… and we all know how that goes.

az wiz · 01-04-2022, 03:01 PM

Quote:

Originally Posted by Morich

I might first ask a couple questions as I see some things I don't understand?
Does this heater have screens to keep bugs out? That is one first thought when fire starts but then stops as the bugs love to get int these small spaces and build nests like in the airflow, so if no screen, I might jump straight to cleaning the airflow and putting screens on to stop the next time!
But I also see what looks like strange color on the air tube. Is it actuall blue like flame is burning in the tube rather than insdie the heater?

That woud tell me for sure there is an air restriction not letting the gas go insdie before igniting!
Is there something odd in three of the vents or just something I'm not used to seeing?

Maybe a check of this manual would be a good guide?

https://epi.dometic.com/externalasse...4379_81175.pdf

Picture is on left side, left side is top (in the pic) Yes it has a screen, is brand new, have run a brush through the tube, nothing inside, tube is blue/black from factory, this is new style wh. Manual is useless, has no trouble shooting section. Have tried calling and emailed Dometic without the courtesy of a reply, nothing new for rv manufacturers! This is in a 2022 Micro Minnie.

Morich · 01-04-2022, 03:26 PM

Okay, answers several things there. Mind if Iturn the picture a bit. They don't come out right if we use a phone and turn it. No big thing!

I do not see any adjustment but several points that I don't know about.
Do I see a black knob at the left side of the burner tube that might turn to adjust air?

I normally think of the air goingin past where the fire burns and then draws the fumes up and out the exhaust but this seems to show a single exhaust with three or six divided portions below. Not at all sure what I'm seeing there, if you know how the air really flows???

But those are just points of interest and maybe not the real question, so how does this beast act? Does it seem to butn okay with the flame fully inside the larger tube. Not inside the small burner tube but at the far end?

Then when it goes out as the door is closed, does it seem to suddenly quit like a valve closes or more of a slow sputtering stop like it runs out of gas or air?

I think I see a gas solenoid at the left side and if the wiring to it gets moved so it loses power, it might be clicking shut to cut off gas? Hear any noise when it stops?

Also the wires behind the center metal piece seem close. Any chance one of them has rubbed bare to short on some metal? Does it do anything odd if you have it running and wiggle the wires one at a time to look for a loose one?

Sorry for all the questions, just shooting in the dark!

az wiz · 01-05-2022, 04:22 AM

Quote:

Originally Posted by Morich

Okay, answers several things there. Mind if Iturn the picture a bit. They don't come out right if we use a phone and turn it. No big thing!

I do not see any adjustment but several points that I don't know about.
Do I see a black knob at the left side of the burner tube that might turn to adjust air?

I normally think of the air goingin past where the fire burns and then draws the fumes up and out the exhaust but this seems to show a single exhaust with three or six divided portions below. Not at all sure what I'm seeing there, if you know how the air really flows???

But those are just points of interest and maybe not the real question, so how does this beast act? Does it seem to butn okay with the flame fully inside the larger tube. Not inside the small burner tube but at the far end?

Then when it goes out as the door is closed, does it seem to suddenly quit like a valve closes or more of a slow sputtering stop like it runs out of gas or air?

I think I see a gas solenoid at the left side and if the wiring to it gets moved so it loses power, it might be clicking shut to cut off gas? Hear any noise when it stops?

Also the wires behind the center metal piece seem close. Any chance one of them has rubbed bare to short on some metal? Does it do anything odd if you have it running and wiggle the wires one at a time to look for a loose one?

Sorry for all the questions, just shooting in the dark!

No knob, no visible adjustments of any kind. Intake (divided portions) is below exhaust, burns in large tube where supposed to, have checked wiring looks ok and tight. Runs fine with door open, close door when running, more of a slow sputtering stop like it runs out of gas or air. Has me baffled!

Morich · 01-05-2022, 09:05 AM

So this sounds like what you have found?
It lights and burns okay but then gradually dies after closing the door. That seems to rule out electrical to me as those mainly work to keep the gas solenoid open at the right time. That solenoid normally opens/closeswith a bit of a click, not gradually, so I lean away from electrical??

But there is a small point that "maybe" I would want to be sure of before going too far.
Do the other gas items like the stove seem to work normally? Not a case of low gas pressure from something like a valve.solenoid, etc only letting gas through slowly to build up and then light but the timing of it running out of gas makes you think the door is what is doing the dirty?
Fishing way out on a limb there but does the heater and stove, etc. all work fine for a longer period, so that it is not tricking you into seeing the wrong thing?

Trying to rule out things like a funky regulator at the gas tank!

**creativepart** · 01-05-2022, 09:36 AM

You might try removing the sealant around the body of the WH were the door seals around it. I don't know the reason for that sealant, but I know others have removed it to get more air in. I saw at least one person on YouTube drilled some holes in the door to let more air in, but that seems pretty dubious.

Try contacting Dometic Water Heater Support.

az wiz · 01-05-2022, 09:48 AM

Everything else (gas) works fine, stove & furnace. I found somewhere it says the wh adjusts automatically to altitude, has to be electronically controlled? Could something wrong with that?

az wiz · 01-05-2022, 09:51 AM

Quote:

Originally Posted by creativepart

You might try removing the sealant around the body of the WH were the door seals around it. I don't know the reason for that sealant, but I know others have removed it to get more air in. I saw at least one person on YouTube drilled some holes in the door to let more air in, but that seems pretty dubious.

Try contacting Dometic Water Heater Support.

As stated in my original post, have called and emailed Dometic to no avail.