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dbiberdorf

American Water Heaters model FG6140S403NOV

18 posts in this topic

I've got an American Water Heaters heater model FG6140S403NOV. Natural gas. The pilot won't stay lit. AWH sent me a replacement pilot assembly (including thermocouple) under warranty. Still no go.

Now they want to send me the gas control valve/thermostat, with me paying the freight ($20), and living with cold water only until TUESDAY! (OK with me, but the womenfolk in my house will be in open revolt by then.)

So...how likely is it that this control valve has failed? (It's a Robert Shaw Unitrol, btw.) Anything else I can check?

Please help me get rid of the cold, grumpy people from my house.

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Need appliance parts? Call 877-803-7957 now!

It's most likely the thermopile flame sensing bulb has failed. That's the little bulb that immersed in the pilot flame. Its job is to prove the pilot is present before it the gas valve open. I think the chances solving your problem with the gas valve they're sending you is near 100%.

On a side note, I think that's exceedingly cool of them to deal with you directly and send you the parts. I'm gonna keep that in mind when I go to replace my gas water heater!

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[user=1]Samurai Appliance Repair Man[/user] wrote:

It's most likely the thermopile flame sensing bulb has failed. That's the little bulb that immersed in the pilot flame.

By thermopile, are you talking about the thermocouple? I know that it is immersed in the flame, causing the gas to the pilot to cut off if the flame goes out. They sent a new thermocouple with the manifold/pilot assembly.

Guess I'll pay my $20 and wait for the gas valve assembly to arrive.

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The thermopile is a the bulb in the flame. Usually, they're factory connected to the gas valve. Could you post a picture of your gas controls and indicate what's been replaced and what they're proposing to send you?

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Good user's manual!

Ah, I know this kind-- they only come out with prayer and fasting. The thermocouple screws into the body of the gas valve. Assuming you have a good pilot flame geometry-- defined as the thermocouple bulb being engulfed in the upper third of the flame cone-- then that new gas valve awwta git it fer ya, budrow.

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The thermocouple is right where it should be.

This'll be my first gas valve transplant.... Anything I should know ahead of time, apart from things like "No Marlboros when working with gas," and "Make sure the life insurance is paid up"?

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It's mostly common sense. But I have some illustrated, annotated help here for your viewing pleasure. Click on each photo to read the accompanying annotations.

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Will I need a new flexible gas line (to go between the supply and cutoff valve and the thermostat/gas valve assembly they send me)?

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Not unless your existing one is damaged. And not unless the geometry has changed... and I don't see why it should unless you're moving the whole water heater.

Otherwise, the flex line disconnects/reconnects to the new valve.

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Not damaged, and I'm changing as little as possible. :)

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HOLD YOUR HORSES!!!!!!!!!!

I believe you can throw all the parts at this that you want and it's not going to fix your problem.  You don't need any parts you need a good cleaning!!!!!!!!

About 2 or 3 years ago I started running into all these new "flammable Vapor Proof water heaters" and problem was always pilot keeps going out.  You can light the pilot and it will pretty much stay burning until you turn the burner on.

If you watch the main burner flame it won't be burning correctly, it will get real lazy and mushy when it burns out it's oxygen and then the flame falls down onto the thermal safety that is in line with the thermal couple and the safety thermal will open or the pilot itself will just go out because of insufficient oxygen supply.

I did some research before finishing this post and found your system is a little different then all the one's I've worked on but same principle and I found a service manual that should guide you to the area that needs cleaned if the problem is as I suspect it to be.

Here's the service manual link: http://www.americanwaterheater.com/support/manuals/flameguard.pdf

See page 20-23

Here's a couple more links about your water heater:

http://www.americanwaterheater.com/products/productDetails.aspx?ID=1006

http://www.americanwaterheater.com/products/pdf/lpfg12.pdf

Here's a good technical bulletin regarding this sytle of FVIR compliant water heater and also an option fiter to install if it's in a dirty/dusty lint filled environment.

http://www.americanwaterheater.com/support/bulletins/TA_5001.pdf

http://www.americanwaterheater.com/support/manuals/FG-Filter.pdf

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Thanks, BAR. I'll double-check that the flame arrestor plate is complete clean, inside and out. If it works, I'll still end up with a new gas valve (having ordered it already, with them being very clear that orders were final), but at the low low cost of shipping for $20.

Will report back.

By the way, Samurai, you might consider presenting users with a login option when they try to reply but without being logged in. It's always a bear to find the login link at the main applianceguru.com page, then come back to what I wanted to do. 

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New pilot assembly, including thermocouple, installed.

New gas valve/thermostat, installed.

I've brushed and vacuumed the flame arrestor grate (where fresh air comes in) as much as I can.

Now I've loosened/tightened everything so many times that I can't get the pilot tube to seal very well (wiggles a bit, letting teensy amounts of gas out).

And, after all this, the #$^ pilot will not stay lit.

Any other ideas? Or must I admit defeat. I can schedule my harakiri for this afternoon.

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[user=267]dbiberdorf[/user] wrote:

Now I've loosened/tightened everything so many times that I can't get the pilot tube to seal very well (wiggles a bit, letting teensy amounts of gas out).

There's gotta be something obvious amiss here cuz the problem can't originate from anywhere else.

That part about the gas leaking, that don't sound so good!  Is it leaking from the connection at the gas valve?  The copper or aluminum tubing may gotten distorted and can't make a secure connection anymore.  May a picture would would the problem. 

Bulb position in the flame is critical-- make sure it's in the upper third of the flame and that the flame mostly pure blue, a yellow pilot flame will not open the valve.

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Realize this info is probably too late to help you but it may benefit someone else in the future. Have a LP fired Maytag manufactured by State with similar problem. Replaced pilot assembly and unit burns for approx 5 min. and then shuts down burner and pilot. Thermocouple has an auto reset thermal limiter inline near pilot. Company says there is a problem with this particular style of heater. Has a ceramic disc filter in center below burner. Dust accumulates on filter and cuts off air flow to chamber. Air flow keeps thermal limiter below shut down temp and allows unit to operate properly. Decreased airflow allows thermal limiter to heat above cutoff temp and shuts unit down. Limiter resets within a couple of minutes and pilot can be relit. Burner comes back on and runs for another 4 or 5 min. before shutting down again. States solution: Fashion a brush(their exact words 'cause it's a bitch  to get to) to reach ceramic disc filter and remove dust build up.

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Knit one, Pearl three !!

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