Wednesday, March 12, 2014

Pilot Light Will Not Stay Lit When Water Is Hot



The pilot light goes out when the burner has heated the water. In the morning, I can light the pilot by pushing the button down and striking the electric igniter. But, once the burner turns off, the pilot can be lit by pushing the button down but it goes out the second the button is released. The pilot looks the same when the water is cold and will stay lit and when the water is hot and it won't stay lit.

What is your make and model hot water heater.
I have $1.00 that says its a AO smith.
If so I can help. Even if its not a AO smith I can still help, but I need the make and model.
Mike NJ

Its a Ruud Pacemaker series 50 gallon residential gas water heater.

What year is the HWH? It may be under warranty and you may just need to pay labor.
These have several saftey devices if its newer.
1. May be t couple. Might be loose at gas valve or sporadic failure.
2. The gas valve may be defective and fails ony on temp rise. The gas valve also has a part to play with the pilot. Is the water abnormally HOT????
3. Combustion Shutoff Device Tripped.( possible resets itself) There is another feature that is a one time use item, but you would not be able to relight. #3 is a door that closes to not allow air in the combustion chamber.
These HWH are not homeowner friendly. With this new technology installing in a dusty enviroment, like by a dryer often causes issues such as this.
I suggest you call Rudd and get a tech to look at it. I could tell you take the burner apart but I advise against it. These are sealed chambers and need to be assembled correctly for saftey reasons.
Mike NJ

I have an ao smith GVR 50 water heater, 5 years old, pilot will not stay lit. Cleaned intake screen, still won't stay lit.
What is next?

Next step is usually to replace the thermocouple. If your pilot is bathing the thermocouple in flame, and the pilot goes out when you release the start button or turn the dial from pilot to normal run, the thermocouple probably needs replacing.

I have an ao smith GVR 50 water heater, 5 years old, pilot will not stay lit. Cleaned intake screen, still won't stay lit.
What is next?
What is the series # of the unit?
These have FVIR technology. The t couplers are part of a whole burner assembly.
If you can give me the serial # I can check for you.
I was a AO Smith rep.
Mike NJ

I had an issue where the pilot would not turn on under any condition. I replaced the thermocouple assembly and gas valve (thermostat) so now the pilot will light and stay on until I move the selector from pilot to on, but once the water in the tank is hot the burner and pilot extinguish completely. The following day I had to do the same thing. Is there a setting or gap on the thermocouple or anything I missed?

What is the make and model heater? What is the serial #.
Mike NJ

I believe it is a AO-GCV50 (Promax 50 gallon residential). The gas valve part number was 182791-006 is now 9000249005. I replaced it and the thermocouple assembly. I appreciate your help! I am not home at the moment, but I can take a lunch to get the serial number if you need it.

what year is it do you think? This way I know what FVIR technology it has.
Mike NJ

The year of the model is 2005

Just verify series 100 correct?
It has a corderite disk and it need cleaning if so but I want to make sure.
Is the unit by a dryer or furnace?
Mike NJ

Yes, it is the 100 series. I replaced the gas valve with the 200 series per the vendor because the 100 had too many problems. The unit is in my garage in an elevated area specifically built for the water heater. I have no other appliances or fuels stored near it. I have enough clearance to walk to and from it and the garage is ventilated (although no breeze comes through). I am not familiar with the corderite disk. Is this the same as the ceramic flame arrestor that is part of the FVIR? If so, it would make sense for me to remove the thermocouple assembly again and find a way to clean the area out. Are there specific cleaing instruction for this unit? The gas valve thermostat came with a very wide filter that I have no idea or even where to install. I looked inside the chamber to see if it had one so I'd get a clue, but I didn't see anything like it. I am confident enough to do the work, but I just need some instruction. Thanks again!

On the bottom of the water heater there is a black lint screen. remove this and get a bright flashlight. Look in the slots and look up on the under side. There is the disk. Air comes in and goes through there for the burner. Does it look like a layer of lint is there?
Let me know and I will instruct you further.
By the way its not the t couple. There is a high temp thermistor that is in line with the t couple. If you changed the t couple with a stote bought one then you put yourself at risk. When these units starve for air it affects the draft and CO poisoning can occur. Basically you can be dead.
These devices reset when the heater cools down below 180C-210C. But it trips for a reason.
I advise to to shut the unit down if you have done this. You have by-passed a saftey feature.
Let me know.
Mike NJ

I purchased the entire t couple assembly at an authorized AO Smith dealer (Ferguson Enterprise), not a hardware store. It is the PSW12204 pilot assembly if that means anything to you. I just checked the black air intake lint screen which was surprisingly clean, but I removed a little surface dust.
I will inspect and clean the radiation shield and flame arrestor in the near future. I'm missing the flexible brush that was supposed to come with the unit, but I will vacuum inside if I can. I believe I have a FVIR type C3 by the way.

Let me know I will be here for another hour or so.
What does it say on the tag on the orange wire from the igniter?
Mike NJ

The one I removed says 180#9675;C 183828-180 760-312. New one says 200#9675;C 183824-200 760-312

New one says 200#9675;C
OK good. Thats the ungraded pilot assembly AO smith new there was a issue so they raised the temp on the thermistor.
If you have your old assembly, its that little round fuse thing in line with the t couple.
OK if you looked in the air vent and up, you probably seen a thin or thick layer of dust? You need to vacuum that. How do you do that you ask?
What I do is get 2 ft of 1/2 copper. Put a ellbow on the end. Get your shop vac and insert the copper end in the vac hose and duct tape it good. What you made is a vac tool. Turn on the vac, and make sure you got good suction from the ellbow. Stick it in the air vent, get the ellbow facing up and vacuum that disk real good. Its about 10 round and you should feel the edge as you vacuum.
Let me know.
Here is some good stuff for ya. They say use a brush but I find a vacuum works better.
http://www.hotwater.com/lit/fvirtechbulletin.pdf
Mike NJ

I was able to get in there a little with a vac, but not nearly as well as I wanted. It appeared to be fairly clean as I found a long delicate brush to gently go over it with, but I want to do a better job with the vacuum. I reassembled everything I think better than before then relit the pilot and it stayed on with no problem. As I adjusted the temperature to warmer temps (between B C) the burner finally kicked on. I am going to have to wait to see if this did the trick for now. I will check in with you tomorrow or the following day. I am definitely going to build myself one of your vacuum tools. Did you ever try using PVC? I'm asking because it's more readily available on this side of the planet. Mike, you are a great help and amazingly creative! I'll talk to you in a few days kind sir.

I am definitely going to build myself one of your vacuum tools. Did you ever try using PVC?
I usually use 3/4 copper but you need to cut the ellbow so it will fit when you turn it up to vacuum the under side of the disk.
You will see what I mean when you do it.
I was going to make a tool and patent it, but AO smith stopped making this series. Its a 200/201 series now with different technology.
What happens is that disk gets clogged and the burner starves for air. The unit does not draft and the flame starts burner down towards the air. It gets close to the thermister that trips at 200C. This shuts the gas off. When it cools down you will be able to re-lite the unit but it will keep happening until you fix the air issue.
AO smith use to have the only resettable thermister. They have a button on the front by the burner window now.
The other companys had a fusible link in the t couple. Once they tripped you would need a whole new pilot assembly every time. These where home store models.
AO smith is ahead of everyone and most adapt the technology from them.
Mike NJ

You should still patent it.. I'd still buy one.
I understand your articulate explanation and appreciate your patience and willingness to teach. Interesting history behind the technology.
Today I took the hottest shower in quite a long, long time. I think the issue is resolved because I can turn the thermostat down and I can hear the roaring flame stop and then start up again when I turn it up again. It wasn't doing that before. I would have to relight it. I am still going to clean it in a week or so. I'll see if I can find 3/4 copper tubing this weekend. I can't tell you enough how much I appreciate your help! Thank you.

Your welcome. Glad I can help.
Mike NJ

I have AO Smith Promax 40(gallon) 100(series) and I ran into the same problem with the pilot light being blown out when the unit turns on itself to heat the water. I hear a loud poof noise and then the pilot light is out, as if being blown out forcefully.
It all happened when a guest is trying to use my upstairs bathroom tonight and there is no hot water upstairs (I don't know how long it has been that way since we rarely go upstairs ourselves). I went to check on the water heater unit in my garage that feeds upstairs and saw the pilot light is not lit. I followed the instructions on the water heater and lit the pilot, it came on fine and started to heat the water. I left it like that and waited half an hour, there is hot water upstairs! Went back to the water heater to replace the cover on the bottom, and saw the pilot light is out again. I re-lit the pilot following the instructions, I guess since the water is still hot so I did not hear the sudden rush of gas and the pilot light stayed on. I waited there for about 5-10 minutes to see if the water heater will start heating itself once the water cools down a little. And when it did you can hear the loud hoosh of gas or fire going up inside the unit like its about the do some major 'heating', but the pilot light goes out quickly like being blown out (with a poof sound) and everything goes quiet. I waited a few minutes and re-lit the pilot a third time. Its been an hour now and the pilot light is still lit...
I wonder if this is going to happen again? I am definitely interested to check tomorrow morning to see if the pilot is still lit. If it is out again, should I shut off gas to the unit and call for service?
Is this a defective part issue? Malfunctioning? Or needs to be cleaned?
Your input is greatly appreciated!

Your pilot lights and your burner flames up so it seems like it may be the same type of issue of just having to clean the unit. I'm not an expert so I'll see what a second opinion or expert would say.

I wonder if this is going to happen again? I am definitely interested to check tomorrow morning to see if the pilot is still lit. If it is out again, should I shut off gas to the unit and call for service?
Is this a defective part issue? Malfunctioning? Or needs to be cleaned?
Read my posts below. #13 and up. Also the link I posted. The disk is clogged and the unit is starving for air. It trips a thermister when the burner is on, because the flame rolls down looking for air and overheats the thermister.
Make a tool and vacuum the underside of the disk as I described.
If you call a professional they most likely will want to sell you a new heater. Most plumbers (service techs) dont know about the new technology and have no clue on troubleshoot or repair them. Most are parts changers and they get paid by the revenue they produce. So to come in your home and vacuum your heater is not what a typical tech will offer. It makes no money. This is why I am not in the trade any longer. Cant rip people off in the tuff economy.
Mike NJ

Hi Mike,
Thanks for all of your good info.
I have an aosmith promax xclv 30 100. pilot wont stay lit, tried cleaning arrestor holes to no avail, have had plumber in twice, he's apparently not online saavy and i feel like i've done so much research on this problem over the 3 weeks i've not had hot water that i know more about the thing than he does.,., ANYway, i'm looking to see if its ok to just remove the glass window from the sealed chamber to allow more air flow. is the sealed chamber a safety measure keeping flame in/combustion air out in case of outside vapors? i keep nothing vaporous/flamable around the unit.
I know the stupid thing works, i can get it to stay lit intermittently and its only 6 yrs old,,,, i have an older model, w/o the fvir sys, in another home and it still works fine,,,,,, i feel like i just want to open the sealed chamber so it will work like the older models... is this thinking correct? I am not a plumber but am frustrated to have to replace the whole unit when i see it working from time to time

Hi.
Thats a 10 yr water heater. You should not have to fix anything regarding parts or tank. You only need to pay labor.
1. If the pilot does not stay lit you need a pilot assembly. Its covered under warranty, and you pay labor. Should be around $99.
2. If the pilot light goes out sporatically, but you are able to light it, it a clogged disk most likely. Read my posts below.
tried cleaning arrestor holes to no avail,
Did you read my links below??? Arrestor holes? Its a ceramic disk. If you take the black lint screen off from the bottom of the heater, then lay your head real low on the floor and look up in the lint screen opening. See a layer of dust? That needs to be vacuumed. You need to make a tool to get in there.
AO smith should change the pilot assembly anyway since they went from a 180celcius thermistor to a 200c. And the guy that comes out should know all this.
Look at the tag on the orange wire. Whats it say? 180c, 190c, 200c?
But if you call AO smith, they will give you the correct plumber to call in your area that repairs them under warranty, and should know clean the disk. You cant just use a plumber off the street.
Open this link and click on the top where it says heater info. Put in your info then call AO smith.
This is for ao smith, state, etc... ( any ao smith product )
https://warranty.hotwater.com/default.aspx
ANYway, i'm looking to see if its ok to just remove the glass window from the sealed chamber to allow more air flow. is the sealed chamber a safety measure keeping flame in/combustion air out in case of outside vapors? i keep nothing vaporous/flamable around the unit.
I know the stupid thing works, i can get it to stay lit intermittently and its only 6 yrs old,,,,
No, no, no. Do not by-pass any saftey device.
I was a rep for AO smith.
Mike NJ

Um i'm sorry that seemingly based on my post youre assuming I havnt read up or performed any of what you suggested.
I mentioned in my post that I cleaned the ceramic flame arrestor holes.
Cleaned it according to the vid sent to me by aosmith:
Standard Gas Control Water Heaters - Filter Cleaning With this included in their response to me:
" If after cleaning the flame arrestor does not correct the issue, the next step would be testing parts, and checking the installation as far a gas pressure, venting, and making sure the water heater is getting the proper combustion air. Thank you, Brandi Technical Support Department "
My unit is not raised so I cant get low enough to see up into the bottom vent holes to see the disc itself, as you suggested.
I have mentioned aosmiths information to my plumber, who I have used and many of my contractor friends have used for decades. (not to say he may not know anything about aosmiths or the ins and outs of the new fvir systems). He has performed their tests and has found everything to be as it should, except for the combustion air obviously...
He will not change out parts, if he sees it as unnecessary, based on testing them as functioning, so I dont have to pay for repairs that arent going to fix the problem, as many have done in most of the forums i"ve read thru.
Been in touch w/aosmith warranty also - Their reply: " If there is no proof of purchase is available, (which I dont have), than the warranty will go by the manufacture date of the water heater which is April 2004, and the water heater came with a six year limited warranty on tank and pars which would of expired April 2010 Thank you, Brandi Technical Support Department "
I"ve been through alot already w/aosmith, which is why I feel like I have to look into things further myself since I havnt gotten anywhere so far and seemingly many others are having the same issue.
I have read all your posts. Over the past weeks I have read many other sites and forums on the subject as well.
One forum I came across had a plumber drill a hole in the arrestor, which seemed to fix this issue. Another forum had someone drill a hole right thru the metal plate near the window, which also solved this problem.
Since you present with some credentials, I wrote to ask your opinion on the opening of the sealed chamber.
I understand it is a safety mechanism, but if it is for vapor block and I dont have that concern....
Again, I just feel like this is a relatively new unit, which again I can get to work intermittently, so I"m trying to avoid having to spend to replace the whole thing,,,
thanks for your time

My unit is not raised so I cant get low enough to see up into the bottom vent holes to see the disc itself, as you suggested.
You need to put you head against the floor basically. You need to see the disk, and it can be seen. Just saying.
Anyway here is a good way to tell if its startving for air.
With the water heater lit, turn the gas valve all the way up so the burner comes on. Look at the flame through the window. It should have a crisp strong flame, that sits above the burner slightly.
If its not like that but wavy, and rolling around its a air issue. Not strong and blue but yellow and rolling down under the burner.
I mentioned in my post that I cleaned the ceramic flame arrestor holes.
Cleaned it according to the vid sent to me by aosmith:
I have found the toilet brush does not work very well. This is from experience. What AO smith should have done ( which I was going to market) is a vacuum attachment made for this purpose. This is what engineers came up with...Uggg.
Also, sometime if the disk is clean, the burner could have debris sitting on top of the burner. This falls down from the flue, and may cause the same symptoms.
Was the burner removed?
Point blank the thermistor is overheating and causing your issue, and or replace the pilot assembly. The thermistor is part of the pilot assembly.
XCV units have always been 10 yr tank models. I believe the parts warranty may have changed from 6 to 10 but I thought is was 2005 sometime.
If you can post your s/n I can see what I can do.
As a professional I cannot recommend any alterations you have stated in your post.
Just a note: One of these water heaters cause a fire, and the house burnt to the ground. The investigation revealed that the disk was drilled out with 5 holes around the perimeter. Its was found to be the homeowner using starter fluid doing a engine repair, plus he drilled the holes in the unit from advice he got on a web site.
His homeowners insurance did not honor his claim. He had no permit either, and the water heater was installed on the floor in the garage, and not 18" high as it should be.
Just a thought.
Mike NJ

Hi lawrosa,
It appears that your extremely technical with the AO Smith units. I can use some of your professional expertise.
I just recently downgraded my home from a 3500 sqft to a 2200 sqft home. I have been in my new home for three months now. The reason why I mention is that my gas bill is almost three times higher then my previous much larger home.
We do not use the oven much as we used to and one thing got me concerned is my water heater.
It is a hit and miss with getting hot water. there are times that I will get up in the morning to take a shower and the water only warm and with the water knob to the shower set to the hottest.
So I decided to set the water heater setting from A to C. After changing it to C I began to get some hot water but it was still a hit and miss. There is times that I would have to run the water at the hotest setting to for about 7 min to even begin getting warm water.
It is a newer home built in 2006. So I decided to call my local gas company PG&E and they sent a technician out to do a safety check. He confirmed that there is no gas leaks and the pilot is on. He told me the reason to my high gas bill is probably because I have set the water heater to its highest setting "C".
I explained to him that I changed that recently and explained why. He said it sounds like that I may have water pressure issues but I don"t because the water flow looks fine in faucets and showers.
I began to research this issue on my own and noticed multiple forums mentioning problems with the AO Smiths water heaters but your posts seem to be the most informational and professional.
I was hoping you may be able to shed some light on my problem?
I have the model GVR 50 100 with a build date of 1/13/2006
any advice will be greatly appreciated!

Asocii,
Do you get hot water out of other faucets and not just the shower? It may be the shower valve itself. They have balancing spools today and they do go faulty.
Also on a not common occurance the dip tubes in the heater itself crack and cause cold water to mix with the hot at the top of the heater. This is instead of the cold water going directly to the bottom of the heater and pushing all the hot water in the tank up and out.
Next you could have a faulty intellivent gas valve, and its not regulating the temp properly.
You need to does some testing to try to determine the exact symptoms.
Also any type of re circ line on your system? Could be bad check valve if you do. Or espeacially if you have thermostatic shower valves are a common cause.
Mike NJ

Thanks for replying Mike...
It is the same symptoms on all faucets... eventually you get hot water out of it after running for quite a while... My concern is not much about how long it takes to eventually get some hot water but if I may be having problems with the heater itself.
I would need to get my brother here to check the things your talking about since his is the handyman in the family. Any procedures that you recommend to test for these cracks that you mentioned? also any other steps you recommend?
Thank you very much for your great input!!!

You know the heater may be borderline under warranty. Its past the 6 yr warranty date if you go by the manufactures date but it goes by when the final CO was issued for the home.
You may need to hurry on this one.
You can get a service guy out and only pay labor costs. Or you can call AO smith and have the parts you need sent for free and install yourself.
I will post back later with additional info on what might be the issue.
Please post exactly what symptoms you have.
I am beginning to think on a long shot if you have a slab home you may have a slab leak on the hot line. This will deplete the HW and cause the burner to fire often to maintain temp.
A good test is to turn off all running water in the home and make sure toilets dont leak. Then look at the water meter to see if its spinning.
If its spinning and you are sure all the water is off then you have a larger issue to deal with.
Mike NJ

Thanks for the reply... If "slab house" means a concrete floor, then yes it is a slab house. Also, the symptom is typically, after running hot water for about 10 minutes you no longer have hot water and just luke-warm borderline cold.
Thanks again!

Check your meter as I descibe.
Let me know if you have meter movement.
If not sounds like a dip tube issue.
Your would be like this and not part of the nipple.
Here is one where its built into the nipple.
Mike NJ

Hello,
State Ind. 40 gal. tank - Nat. gas
Mod # PR640NBRT971
Ser # D99106061
Is it just a matter of replacing the T-coupler as it says elsewhere as a solution to this problem?(do I need to remove & bring w/ me to source replacement?)
Can I use generic replacement or must I get a specific manufacturer replacement?
Thanks for the help!
Gotta go, gotta throw!

I believe 1999 water heater takes standard replacement. 18" I believe.
Mike NJ

lawrosa
I have 6.5 year old AOS Promax GCV 50 100 that is acting up.
I have vacummed the underside of the disk as your earlier posts recommend. However, my sight glass has a thick residue that makes visibilty of the pilot impossible and the full burner fire difficult to observe. Debris build up is evident on the top of the burner. Some blue flames point up and some point down. I believe the disk is blocked by debris. The white gasket for the window and the burner panel is also discolored.
In your experience is this a burner cleaning event or burner replacement event that I need to pursue?

I
n your experience is this a burner cleaning event or burner replacement event that I need to pursue?
Clean the burner and check the flue for debris or obstruction. If you have the disk and cleaned from the underside its always good to remove the burner and clean from the inside also.
Mike NJ
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Tags: pilot, light, stay, water, water heater, pilot light, pilot assembly, sealed chamber, lint screen, appreciate your, being blown