Oven Burner Repair?

[SteveR]

We've had a Jenn-Air range/broiler/oven for about 15 years. The oven burner started making disconcerting popping and "whoomp" noises, mainly when it reaches temperature and shuts off. I changed the igniter with no change. I thought it might be the gas valve, but had a repairman come out to check. He diagnosed a hole in the burner tube caused by it's proximity to the hot igniter. We are unable to find a replacement as it has been discontinued. If I can repair it, it will make it easier to buy more tools and live steam parts, which would be way better than a new stove!

Here's a picture of the burner:

And a close up:

I have a couple of ideas that start with grinding it flat and cleaning it up:
1) Weld and drill some similar sized holes
2) Stainless hose clamp - with or without holes?
3) Tantalum wire over tantalum foil (Melt point is >5000F and is available from MMC) - holes?

Easier or better solutions welcome!
Thanks,
SteveR

[Harold_V]

It looks to me like you could sleeve the burner. Using a piece of stainless (304 or 316 would work), machine a thin-walled sleeve that will cover the damaged area. If it can be placed without destroying the tube, a press fit would do nicely. If it can't, then a touch of silver solder should keep the sleeve in place. You'll lose a tiny portion of the burner, but I suspect that won't make much difference in performance.

How does the igniter work? Is an arc created between the igniter and the burner at the damaged location? If so, the sleeve will be much harder to destroy than the original tube. Consider that if you decide to fix the burner this way. The thicker the sleeve, the longer it will last.

H

[Bill Shields]

Weld it up and forget the holes

[SteveR]

Hi Harold,
Sorry - In order to show the hole in the first picture, the tube is rotated about its long axis such that the mounting flange at the top is viewed end-on. If the tube is rotated 90 degrees around the long axis, you would see that it is wider than the tube diameter. Similar problem at the bottom of the picture, where they smashed the tube into the shape of a venturi to draw air in with the gas.

The igniter is a shaped ceramic resistor that glows almost white hot and it sits maybe 1/4" from this burner tube - here's a picture:

Bill,
That was my first comment to the repair guys when they said it was unobtainium. However, since it's the most invasive of the 4 options, I think I'll hold off for now.

The plan is to start with a thin SS hose clamp.

Thanks,
SteveR

[Harold_V]

Interesting. The hose clamp is likely to work just fine. I suspect that the problem you had previously was too much gas escaping from the large hole that has eroded. The hose clamp will restrict the opening and still provide an orifice of sorts. I'd enjoy hearing how this shakes out. I like solving puzzles like this.

H

[SteveR]

All good. I used a piece of 15mil shim stock to cover the hole and the hose clamp to hold it in place.
Harold - you're probably correct about the holes in the clamp, but I didn't want to turn it into a research project. Probably something about a critical maximum orifice size....

Here's the hole after a bit of cleanup:

Here's the fix:

Here's a picture of the overall part. They start with a piece of tubing and then smash one end into a venturi and smash the other end closed for mounting. Not sure how they make all the holes, but they look punched.

Adapt and innovate!
Thanks,
SteveR

[Harold_V]

Looks good! Does it work as hoped?

H

[BigDumbDinosaur]

Here's a picture of the overall part.

Any photos of the house after you lit the oven and the stove blew up?

Just kidding!

[SteveR]

Mixed results so far. The burner functions and the flame looks good, but occasionally will still not go out properly. I may take the shim stock out and just use the hose clamp. House still in one piece - so I've got that going for me, which is nice

SteveR

[Harold_V]

Mixed results so far. The burner functions and the flame looks good, but occasionally will still not go out properly.

Hmmm. How so? What does it do? Seems to me that if the fuel supply is stopped, it has little option but to go out.

I may take the shim stock out and just use the hose clamp.

If you do, how about an update?

H

[Bill Shields]

Not going out properly?..or burning inside of the burner itself?


Could be that at low flows the gas out the larger irregular hole could be entraining air into the pipe elsewhere creating a combustible mixture inside the burner that then ignites and causes the woofing sound.

I have personally had furnace burners (commercial and home made) that did not turn down well and would allow air into the burner while still hot and gaseous..causing what you describe.

Ever look at a furnace burner? They tend to be necked down toward the non feed end to maintain constant minimum velocity of gas flow to keep what you are describing from happening...burning inside the burner

I would consider using a dab of furnace cement to fill in the big hole...and cover it with the screw clamp.

[SteveR]

Sorry for the delay - Collecting data. Seems to be significantly better, but didn't have time to get into it today. The plan is to open things up again and get a better visual on where the flame goes during startup and shutdown.

Just so happens that I recently bought some furnace cement (MMC #9372K85) for a little heat treat furnace I'm trying to build. Will take Bill's advice and pack some in under the clamp to really make a nice seal.

More in a couple days.

SteveR