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MojaveJoe · 01-17-2010, 05:50 PM

That is.....it won't stay lit with the outside access door closed. It burns for about 1-2 min then goes out. The red light on the control switch comes on, it waits for about 30 seconds then lights again. This cycle goes on and on. The flame sounds like it's burning erratically, as if almost going out every few seconds, until it finally does.

Weird part is, if I open the outside door it will stay lit for a long time, even with wind blowing directly on the burner. It's almost as if it's running out of air with the door closed.

I have cleaned the burner tube, the orifice, and inside the combustion chamber. Even took a wire brush to the 2 wires at the end of the burner tube (igniter?) Same problem after I did all that.

All advice or experiences welcome.

P.S. Model: SW6 DE

Roadking · 01-17-2010, 09:47 PM

I had a very similar problem with my Attwood WH. It would burn erratic, or would burn only 30 seconds or so and go out causing the controller to re-lite. It worked fine when the outside door was open, or propped open just an inch or so. I read somewhere the two doors sealed so good they actually did restrict the fresh air flow. I drilled about a dozen half inch holes in the inner WH door and covered these with a screened vent. The now WH burns steady and stays lit.

MojaveJoe · 01-18-2010, 08:19 AM

Thanks Roadking.
Exactly where did you drill the holes? Ive been considering that fix, but not sure best place to create a new vent hole. My WH door is outside, w/ no secondary door.

lashmarry · 01-31-2010, 09:10 AM

MojaveJoe I have a SW10DE I was looking at my water heater, and if I were to drill holes in my out side door I would drill a few small holes in the lower left hand corner stright across form the burner tube air intake / orifice is at.
at what altitude are you operating your unit, it may need to be derated. what color is your flame. make sure that all the connections are tight and not leaking ( mix some dish washing soap and water. spray it on your inlet lines and look for bubbles. check your orifice. It sounds like your gas - air mixture is not correct, or that the combustion gases are reintering the system. make sure all path ways are clear with no obstructions, vent screen, burner box. let us know what you find.

Bradley-Berg · 02-10-2010, 11:49 PM

Quote:

Originally Posted by mojavejoe

that is.....it won't stay lit with the outside access door closed. It burns for about 1-2 min then goes out. The red light on the control switch comes on, it waits for about 30 seconds then lights again. This cycle goes on and on. The flame sounds like it's burning erratically, as if almost going out every few seconds, until it finally does.

Weird part is, if i open the outside door it will stay lit for a long time, even with wind blowing directly on the burner. It's almost as if it's running out of air with the door closed.

I have cleaned the burner tube, the orifice, and inside the combustion chamber. Even took a wire brush to the 2 wires at the end of the burner tube (igniter?) same problem after i did all that.

All advice or experiences welcome.

P.s. Model: Sw6 de

hello,
more than likely, it is your burner tube that is out of adjustment. If, it would not stay lit for more than a minute regardless of the door then it would be the board, or the flame sensing unit.

Directly facing you on the burner tube is the top of a 1/4 screw, right in the middle of those oblong slots running horizontally. If, you losen that screw that burner tube will slide in either direction 1/4 to 1/2inch... That is the "air/fuel mixture adjustment. It needs to be running when you adjust it. Obviously the tube will be hot so just tap it with the 1/4" nut driver you used to loosen the screw with. It sounds like it needs to go to the right (tube) which will make the oblong slots longer and allow more air in. I would bet thats it.

Ideally, you want a blue(r) flame with a small yellow tip at the end of the burner tube. But of coares do what ever "color" you can get to make it stay running.
I hope that was of some use to you.

Brad
portland, ore
on-site rv repair

skyhi1 · 02-19-2010, 11:37 AM

try replacing your igniter i worked for a rv dealer and we had a lot of problems with the hw. they look fine but there is usually a hairline crack. the customers didnt believe me until i would swap out the igniters in front of them and they had no more problem. if adjusting the tube doesnt work this probably will

Roadking · 02-23-2010, 10:59 AM

MohaveJO -- did you resolve the problem yet?

Skyhi1 suggested replacing the igniter. The igniter indeed could be a problem as the igniter also functions as the flame detector. If the igniter fails to detect the flame then the control board removes power from the propane control valve, thus stoping the propane flow. When this happens you should be able to hear the propane valve actually "click" closed. Igniter detection failure sually happens just seconds (3-5) after ignition. You need to verify the valve is closing, vice the flame extinguishing from lack of oxygen.

As Bradley-Berg suggested, try adjusting the oxygen mixture as stated in his post. You should be able to adjust the flame from minimal yellow (not good as excessive CO) to a strong flame that sounds like a blast furnance (to much). Once adjusted close your access doors and if the sound of the burner changes after about 30 to 45 seconds then the burner is being starved for oxygen meaning the oxygen flow is being restricted.

I drilled about a dozen 1/4 inch holes in region located slighly below the burner in a general pattern covering a circle about 3 inches in diameter. These were drilled in the metal water heater cover which is then covered via the compartment hatch door. Since drilling the holes the heater flame has not failed at any elevation from sealevel to over 10,000 feet. When staying for extended periods at different elevations (sealevel to rocky mountains) I have made minor adjustments to the oxygen mixture as described in Bradley-Berg's post. I only did this to elimate the annoying "blast-furnance" sound.

MojaveJoe · 02-23-2010, 12:16 PM

Great info guys...thanks.

I have no adjustment for the flame oxygen on my burner tube. Just fixed openings near the orifice.

I have a good jet like sound and a blue flame only slightly yellow tipped.

Over the last month I ran the WH with the door cracked open only 1/4" at top.
Never had any problem with it re-igniting.

Makes no sense that it worked new with door closed but now doesn't.
I will probably add some extra air inlets in the door near the orifice and see what happens. For right now I'll keep using the cracked open door method.

If I find any other info I will try and remember to post it.

P.S. I cleaned the inside of the burner tube by shoving a piece of steel wool thru several times. Is there a better way to clean the spider webs etc from inside that tube? Then again, if that were the problem, having the door wide open wouldn't help, I guess.