# Used Rheem 50gal water heater - Pilot won't light...Any ideas?



## Grampa Bud (Apr 6, 2009)

That used to be Rheems standard direct vent 50 gallon model before power vents came along. Even new that piezo-electric ignitor was shaky (Probably made in China). Don't rely on it or you may have an even brighter flash some time.
Depending on how long you had the gas line open while you were repiping the heater you could have a large bubble of air trapped in the main gas line somewhere. If you saw a small flash when you tried it the first time (lighting the pilot) some of that bubble is getting bled off. Get yourself a butane fired "stick" lighter; about $1, with a 6-7 inch long tip on it and continue to try lighting it just as the directions say, but without using the piezo lighter. If the pilot won't remain lit after after you have flame for a minute or so replace the thermocouple. Make sure you look at the face of the gas valve also because some of them had a "pilot light" position and anywhere else on the dial let to much pressure through to light and sustain the pilot. DO NOT TAKE THE GAS VALVE OFF OR APART.


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## AllanJ (Nov 24, 2007)

Holding down the pilot-gas button but not pressing the piezo button will also bleed off the air pocket although how long to hold it down is guesswork.

To be safe, do this:

Use bellows to blow out the underside of the water heater. Hold down the pilot-gas button, wait three seconds, press the piezo button once, and see if the pilot light came on. If not, keep holding the pilot-gas button for two to three minutes. Let go and go away for five minutes to let gas dissipate just in case the air pocket was small and lots of gas came out. Repeat.

If the pilot won't light while you have the pilot-gas button held down, the thermocouple is probably not the cause.

After the pilot light comes on, hold the pilot button for another 60 seconds. Then, if the pilot light goes off when you let go, the thermocouple is suspect.


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## xmjm924x (Mar 7, 2011)

Thanks for all of your helpful replies people! With some good feedback and a helpful suggestion from a member of a different DIY forum, I was finally able to identify the problem and ultimately succeed in getting the pilot lit. After purging the gas line a few times with no success, I decided to completely disconnect the gas-supply line from both ends and blow it out repeatedly with about 120 psi from a compressor. It was that last attempt at finding a solution that without-a-doubt took care of the problem. The pilot is now lit and I am finally able to enjoy a hot shower for the first time in two hellish weeks (lol). Thanks again for all your help guys!...You really helped make a difference in my situation!:thumbup:

-Mike


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## how (Feb 26, 2011)

I'm glad you've fixed it but your method makes little sense to me . Just what do you think you cleared from your main gas line that would of helped?


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## frnkhtc47 (Apr 26, 2011)

using compressed air probably blew out rust from inside of the gas line.


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## Grampa Bud (Apr 6, 2009)

If it was really rust- That had to be one Hell of a pile of it to stop that little whiff.


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## veesubotee (Nov 22, 2008)

Considering my (non-pro) experience with water heaters over the years, when lighting the pilot, the thermocouple doesn't affect the flow of gas to the pilot flame: hence the need to 'hold down' the button to allow gas to flow through it, and turn the valve switch to 'pilot'.

Once the pilot is established, releasing the button and turning the switch to 'on' (or whatever), will allow the thermocouple to 'control' the gas valve.

V


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## Grampa Bud (Apr 6, 2009)

Actually the thermocouple DOES affect the flow of gas to the pilot flame. The thermocouple replaces your thumb or finger pushing down on the button for the gas valve. By pushing down on the gas valve button you are opening a small poppet valve within the main gas valve body that will allow a predetermined amount of gas (small but adjustable) through to the pilot assembly. Once the pilot has been lit the thermocouple heats up rapidly (about 45 seconds) and the contents of the thermocouple capillary tube puts enough pressure on the button end of the tube inside the main gas valve to keep the pilot poppet valve open just enough to maintain the pilot flame. After the pilot flame has been established the thermostat for the water heater (also adjustable) takes over and by your setting - LOW - MEDIUM - HIGH - will open the main gas valve poppet for the main burner for as long as needed. If the gas pressure to the heater drops for some reason or the thermocouple goes bad, the pilot will extinguish and both poppets in the main valve body will close. The main gas WILL NOT WORK without the pilot and thermocouple functioning properly.


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## sublimesed (May 10, 2011)

I know I shouldn't piggy back the OP's thread, but I have a similar issue however my Rheem Fury 42v50-40F (manufactured in 2004) was working yesterday and stopped last night. It has been working the past 2 years I have lived here. 

I have gotten the pilot light to relight twice but when I move it to the ON setting it just goes out.

Any tips would be appreciated. Thanks in advance.

EDIT: after reading these posts more thoroughly I am going to assume that would suggest it is the thermocouple. Please let me know if my assumption is wrong


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## how (Feb 26, 2011)

If you can get the pilot to light and stay on in the pilot position with your fingers off the valve, and it goes off *immediately* when you turn the gas valve control to "on", then the gas valve itself is suspect.


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## sublimesed (May 10, 2011)

how said:


> If you can get the pilot to light and stay on in the pilot position with your fingers off the valve, and it goes off *immediately* when you turn the gas valve control to "on", then the gas valve itself is suspect.


Do you have a site, other than eHow, you recommend to follow for replacing this? 

I really dislike that site generally take that site's advice with a grain of salt.


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## how (Feb 26, 2011)

Hey Sublimesed
Is there a freebee site of advise that you shouldn't take with a grain of salt?
Changing your own gas valve has some variables to it that make me nervous recomending it as a do it yourself project. 

You should also post a couple of pic's first of the gas valve from a couple of angles just to make sure there isn't any odd pilot controls that I've missed. There are a hundred plus different gas valves out there.


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## sublimesed (May 10, 2011)

how said:


> Hey Sublimesed
> Is there a freebee site of advise that you shouldn't take with a grain of salt?
> Changing your own gas valve has some variables to it that make me nervous recomending it as a do it yourself project.
> 
> You should also post a couple of pic's first of the gas valve from a couple of angles just to make sure there isn't any odd pilot controls that I've missed. There are a hundred plus different gas valves out there.


Well said...

Thanks! I will do that as soon as possible.


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## sublimesed (May 10, 2011)

I have them attached for you..let me know if you need anymore pictures. It is hard to take pictures because there is a table with a lot of stuff on it in the way, but if need be I can move it.

Nevermind the lent..it is in a laundry room


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## Grampa Bud (Apr 6, 2009)

You should check that the pilot flame is bathing the end of the thermocouple in flame first. If the flame is beside the end of the thermocouple probe there is a chance the pilot flame is a gnats heartbeat from going out anyway. The probe has to be buried in the flame or there is not enough pressure to hold the valves open. While you are down there shine a strong flashlight into the firebox and see how much rust debris is in the firebox and in particular covering the top of the main gas burner. It looks loke a 4-5" plate with holes around the edge in the middle of the firebox. The most you should ever see in there is about a teaspoonfull. Use the snorkel tool on your vacuum to reach in there and clean it all out if you need too. If you do these two things and it still turns off as soon as you raise the temp on the dial go to your hardware store and get a replacement thermocouple and put it in. It's real simple. Only after you have tried these three things should you even consider the gas valve. As a rule the valves on Rheem 40 and 50 gallon heaters hardly ever go bad. In fifteen years and 200+ heaters I only had to change 2 valves and one of those was because the factory had put a propane valve on a natural gas heater.

OOOPS!! I just saw your pics. You have a sealed combustion chamber and Rheem will void the warranty if anyone goes in and attempts to repair anything inside it. We were told by Rheem that this type of firebox has to be REPLACED if anything goes bad and only by their authorized repair centers. Check to see if the air door under the heater has tripped shut or if it is blocked by debris and/or dust or lint. You can sustain a pilot with the air door closed, but the main burner will cause a shut down like this if it can't get any air. Sorry.


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## sublimesed (May 10, 2011)

Grampa Bud said:


> You should check that the pilot flame is bathing the end of the thermocouple in flame first. If the flame is beside the end of the thermocouple probe there is a chance the pilot flame is a gnats heartbeat from going out anyway. The probe has to be buried in the flame or there is not enough pressure to hold the valves open. While you are down there shine a strong flashlight into the firebox and see how much rust debris is in the firebox and in particular covering the top of the main gas burner. It looks loke a 4-5" plate with holes around the edge in the middle of the firebox. The most you should ever see in there is about a teaspoonfull. Use the snorkel tool on your vacuum to reach in there and clean it all out if you need too. If you do these two things and it still turns off as soon as you raise the temp on the dial go to your hardware store and get a replacement thermocouple and put it in. It's real simple. Only after you have tried these three things should you even consider the gas valve. As a rule the valves on Rheem 40 and 50 gallon heaters hardly ever go bad. In fifteen years and 200+ heaters I only had to change 2 valves and one of those was because the factory had put a propane valve on a natural gas heater.
> 
> OOOPS!! I just saw your pics. You have a sealed combustion chamber and Rheem will void the warranty if anyone goes in and attempts to repair anything inside it. We were told by Rheem that this type of firebox has to be REPLACED if anything goes bad and only by their authorized repair centers. Check to see if the air door under the heater has tripped shut or if it is blocked by debris and/or dust or lint. You can sustain a pilot with the air door closed, but the main burner will cause a shut down like this if it can't get any air. Sorry.


Well there is no warranty to be voided so I guess I can check the air door, any other advice since there is not a warranty to void?


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## sublimesed (May 10, 2011)

Furthermore what exactly do you mean by Air Door?

EDIT: I think you may be referring to this? http://onsmartpages.com/weilhammerplumbingco/nss-folder/pictures/DSC09018.jpg

I am not seeing that in my model's manual: http://globalimageserver.com/fetchDocument.aspx?id=01091171-3bac-4cb9-a0a8-a11aac3bd668


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## jbjones (Apr 7, 2011)

I take it the water heater has a 6 year warranty. GE ? Call the 800 number listed by the model sticker on the top. The tech people are good at trouble shooting the problem. But they might not help you if your out of warranty. It doesn't hurt to try. There is a glass piece under the burner in the combustion chamber(I forget what it's called). It is designed the break if the air mixture somehow gets screwed up. If that breaks, you won't get it going no matter what you do. You have to open the combustion chamber to check it. If you do that, you are supposed to replace the gasket. They sent me a kit with both in it. But I was still under warranty.


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## sublimesed (May 10, 2011)

jbjones said:


> I take it the water heater has a 6 year warranty. GE ? Call the 800 number listed by the model sticker on the top. The tech people are good at trouble shooting the problem. But they might not help you if your out of warranty. It doesn't hurt to try. There is a glass piece under the burner in the combustion chamber(I forget what it's called). It is designed the break if the air mixture somehow gets screwed up. If that breaks, you won't get it going no matter what you do. You have to open the combustion chamber to check it. If you do that, you are supposed to replace the gasket. They sent me a kit with both in it. But I was still under warranty.


It is actually not under warranty, I called them today. And it is a Rheem Water Heater. The manual is saying that the combustion shutoff system has tripped..does that help any?


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## sublimesed (May 10, 2011)

More Detailed image of the internal system can be found here: http://globalimageserver.com/fetchDocument.aspx?id=2e771cc5-8ccf-40ac-8d6f-6d3316afca2a


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## jbjones (Apr 7, 2011)

So they wouldn't help? I believe the shutoff switch is the same thing I was talking about. I had similar problems with my GE heater(made by Rheem) that looks exactly like the pictures you posted. I would assume it is the same. The glass holds the switch down. When it pops, the switch comes up and prevents the gas valve from letting gas in. I don't know if you can buy the glass. They sent me one cuz I was still under warranty. I installed it myself with the help of a licensed plumber on the phone cuz he was too busy to come. That fixed the problem, but it happened again a year later. They said since it happened already they just replaced the entire unit. You might have to replace yours. If you want to know for sure, you can remove the combustion chamber door and look on the bottom for little pieces of glass.


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## jbjones (Apr 7, 2011)

If that glass deal is still in tact, you can try replacing the pilot assembly. You can find them online. The thermocouple comes with it. They are somewhere around $40. You can't buy the thermalcouple separate.


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## how (Feb 26, 2011)

If your pilot can be lit and will stay on with the gas control in the pilot position And will stay on with your hands off the controls but goes out the instant you turn the control from "pilot" to "on", you need to have the gas valve changed.
The dummy question is to make sure you are not mixing up the "on " position for the "off" postion.

If your pilot can be lit and will stay on with the gas control in the pilot position but goes out as soon as you let your hands off the controls then it could be the thermocouple, thermocouple position, pilot orifice, inline limit switch( i didn't see one in your pic's) or the gas valve. 

Note # unclamping the gas valve from a hot water tank is very hard on the glass lining of the tank and can often lead to a leaking tank. Compare the labour & gas valve costs on fixing a 6yr + tank against the price of a new tank.


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## Grampa Bud (Apr 6, 2009)

Sublimesed: the combustion shut off system IS the air door I spoke of. It's that round metal disc they show in the bottom of the picture. We were never allowed to mess with a heater where the air door was tripped so I don't know how or if it is actually tied to the gas valve. The manual indicates some form of tie, but they don't show any.Try lifting or opening the door with a 1/4 or 3/8 drill bit on one side and reliting the heater. If the main comes on after lighting the pilot you have your answer and you can talk to Rheem about how to repair the "Combustion Shut Off System".


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