New hotwater heater flaming out

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New hotwater heater flaming out

April 06, 2020, 01:38:41 pm

Had my 10 gallon replaced this winter by my RV shop. Now that I have water in it, I tried it out and upon cold startup, it keeps going out. Took it out to them and they said it doesn't have enough airflow thru the door! I don't believe it. Worked in all my other campers with the standard vent in the door as the FT has. Only cold startup, works on demand after hot
Any opinions? It's a standard 10 gallon with the heater assist. Dometic-Atwood

Re: New hotwater heater flaming out

Reply #1 – April 06, 2020, 02:52:58 pm

I agree with you, you should be able to show them their theory is false by opening the basement door and trying to ignite the water heater.

You might have to bypass the switch that shuts down the heater when the door is open or figure out a way to hold the button in on that switch.

At one time my water heater would not ignite and it was that the compartment door was not all the way closed.

Re: New hotwater heater flaming out

Reply #2 – April 06, 2020, 03:06:44 pm

Try it with the door open. Check the color of the flame. Adjust the air away from a "soft" flame with possible yellow color to part of it to a "harder" blue flame. Try starting it with both the door open and closed. Don't trust a shop to know what they are doing. Review your heater's installation/user manual online for instruction. Could the spark device have been damaged in shipping or installation?

Pierce

Re: New hotwater heater flaming out

Reply #3 – April 07, 2020, 10:06:41 am

Quote from: dans96u295ft – April 06, 2020, 01:38:41 pm

Had my 10 gallon replaced this winter by my RV shop. Now that I have water in it, I tried it out and upon cold startup, it keeps going out. Took it out to them and they said it doesn't have enough airflow thru the door! I don't believe it. Worked in all my other campers with the standard vent in the door as the FT has. Only cold startup, works on demand after hot
Any opinions? It's a standard 10 gallon with the heater assist. Dometic-Atwood

I have converted two of my water heaters, the previous RV and this one to Meker style burners. I take out the burner tube and dismantle the stuff on the end where the flame forms, make a screen out of a metal window screen patch formed over a coin or whatever fits and press in place. Re-assemble, install and test. Now the burner can be adjusted for a nice clean multipoint flame without the risk of flash back.

It has been pointed out to me that this modification does require some mechanical skills and some knowledge of propane technology. Please ask yourself if you are comfortable with your skill set, and if not, hire someone to help.

Re: New hotwater heater flaming out

Reply #4 – April 07, 2020, 01:29:42 pm

Appreciate that Toolmaker. I just want this one to work. It's new and under warranty so I don't want to modify it yet

Re: New hotwater heater flaming out

Reply #5 – April 07, 2020, 07:54:47 pm

Does it work with bay door open, if so it does not have enough air flow.

Re: New hotwater heater flaming out

Reply #6 – April 07, 2020, 09:54:20 pm

Quote from: dans96u295ft – April 07, 2020, 01:29:42 pm

Appreciate that Toolmaker. I just want this one to work. It's new and under warranty so I don't want to modify it yet

Just for the fun of it, carefully pull the burner so no one knows you've voided the warranty. Using the proper wrench, once again to leave no tell tale marks, remove the gas jet. Check for anything small and light that could be floating around in the gas stream. Do NOT use anything to "clean" the orifice. Maybe a spritz of carb or electronic cleaner. Upon assembly make sure the burner tube makes a straight line away from the gas jet so the jet of propane doesn't impinge on the sides of the tube.

Re: New hotwater heater flaming out

Reply #7 – April 08, 2020, 12:15:32 am

When I close the door the noise the flame makes changes and sounds different. This was a replacement for the original heater which was the same size and design. How would it be starving for air when the others worked with the door closed. I also replaced the entire main gas regulator at the tank this winter. The furnaces and stove work fine with the new regulator. Toolmaker I appreciate your suggestion and will give it a try. Very confusing issue. The tech that thought it's an air issue has 25 years in the business but that doesn't always mean a lot.

Re: New hotwater heater flaming out

Reply #8 – April 08, 2020, 08:51:38 am

Do you not have the "slide to adjust air" burner tube on your new water heater? Is it all the way open (max air) and still too rich?

Gas pressure not too high-- should be 11 inches water column.

Re: New hotwater heater flaming out

Reply #9 – April 08, 2020, 09:01:48 am

Quote from: dans96u295ft – April 08, 2020, 12:15:32 am

When I close the door the noise the flame makes changes and sounds different.

That's because the proper air flow depends on the door being closed.

Re: New hotwater heater flaming out

Reply #10 – April 08, 2020, 10:11:37 am

It does have the adjustable air slide on the tube. I'll call my other dealer and see if they can test water column pressure. Most techs just don't know this stuff

Re: New hotwater heater flaming out

Reply #11 – April 08, 2020, 10:16:44 am

Have you adjusted the air slide? To what effect?

If you have to drive and pay labor to check propane pressure, particularly if your regulator is old, cheaper to just replace it-- around $25.

Re: New hotwater heater flaming out

Reply #12 – April 08, 2020, 10:35:28 am

Great idea and advice from Wolfe, least expensive route is definitely replacing the regulatoron on the propane tank.

That being said a tech advised me 15 years ago to buy a manometer test kit. I found the easiest place to test is on the top of my propane cooktop in the kitchen area.

Google, manometer-propane-rv, and you should find others input on pressure testing the rv propane system. Follow all safety advice for use. They cost less than a half hour shop labor charge.

It not only tests for proper pressure regulation, by leaving it on for a suggested period of time you also are checking for a leak.

I've used it to test my regulator, and anytime I opened the propane plumbing system. It is important to test for a possible leak anytime you do this. This is so important our service department manometer tested every used rv sold for safety reasons and to prevent comebacks.

Re: New hotwater heater flaming out

Reply #13 – April 08, 2020, 10:37:41 am

Wolf, do you mean the regulator on the heater? I've already replaced the regulator at the propane tank

Re: New hotwater heater flaming out

Reply #14 – April 08, 2020, 10:39:12 am

No, I was referring to the regulator at the tank.

Again, what were the results of adjusting the air tube?

Re: New hotwater heater flaming out

Reply #15 – April 08, 2020, 10:42:13 am

I'll adjust it today and see. I know the tech moved it around when testing but I was just observing , not thinking he would give up.

Re: New hotwater heater flaming out

Reply #16 – April 08, 2020, 12:00:14 pm

If closing the door made performance worse/more "blow torch sound", then open the air slide more.

BUT, it is really hard to adjust mixture over the internet.

Re: New hotwater heater flaming out

Reply #17 – April 08, 2020, 12:11:30 pm

Doesn't help your problem but it sounds like your "shop" doesn't test when they install something.

Re: New hotwater heater flaming out

Reply #18 – April 08, 2020, 12:23:53 pm

Ok. I'm playing with the air slide and may have fixed it. News to follow at 5pm. Ha Ha

Re: New hotwater heater flaming out

Reply #19 – April 08, 2020, 05:13:26 pm

I have had a similar problem with my 10 gallon Atwood water heater. When cool outside (40 or 50F) and water heater has not been turned on for a few days, when ignition occurs, there is a pop sound and the flame goes out. This occurs because the flame front has gone back up the burner tube to the jet and blown itself out. When it is warm outside or heater is left on all day this does not happen. My fix is to open the cargo door (my water heater does not have a door shutoff switch) and ignite with a torch.

Thanks to Old Toolmaker for the tip on the Meker burner, I may do that conversion to the water heater because it may fix the blow out I am having. Could the refrigerator burner be converted to a Meker burner also to make it burn hotter. The folks at RVcooling unit told me that refrigerators stay colder when on 120 VAC, because heating elements provide more heat than the propane flame does.

The eleven inches of water column that Brett mentioned is the same as 6.3 ounces per square inch. The ounce gauge I installed shows 7.3 because I replace the pressure regulator at the tank, which was leaking, with an adjustable one so that I could increase the pressure to get more pressure for the refrigerator so it stays cooler on 100F days. The furnaces and stovetop seem to work just fine with this increased pressure.

Does anyone know if 7.3 oz/square inch will cause problems? I will turn the pressure back down to 6.5 and see if the heater blow out stops happening.

To clean a brass orifice, I remove it and drop it in a shot glass of vinegar overnight, then rinse with water and blow dry.

Re: New hotwater heater flaming out

Reply #20 – April 08, 2020, 06:38:17 pm

Search for Fisher ounce gauge,can be had for $25.

Re: New hotwater heater flaming out

Reply #21 – April 09, 2020, 03:15:46 pm

I lowered the propane output from the regulator to 6.3 oz/sq inch and observed the following:

The water heater ignited correctly when cold, but the blow back flame out was happening intermittently so wont know if the cold startup flameout will happen again for several months. Joan and I returned from California a month earlier then planned due to COVID-19 so are in quarantine for another week, planned group campouts have been cancelled until June, and all BC Provincial Campgounds are closed until July.

The stove top burner flames are slightly smaller with less yellow (did not increase air with 7.3 oz/sq inch).

The refrigerator, which also occasionally had blowout on ignition, ignited correctly but with a slightly smaller flame.

The recommendation to increase the regulator output by one oz/sq inch came from RVcoolingUnit.com. It seems that it was not good advice.

Re: New hotwater heater flaming out

Reply #22 – April 09, 2020, 03:17:41 pm

Good to know. Were learning for sure!!!!

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