Flame Guard and Flame Lock Gas Water Heaters are made by American Water Heater Company and sold under the names American Proline, Whirlpool, Envirotemp, Mor-Flo, Powerflex, Premier Plus, US Craftmaster and possibly others. The Flame Guard and Flame Lock are names for FVIR (Flammable Vapor Ignition Resistant) Technology designed and manufactured by American Water Heaters. FVIR is a required safety design on gas water heaters that includes a sealed combustion chamber with a flame arresting barrier on the combustion air inlet and a device that detects a taller burner or pilot flame and shuts off the gas supply to the burner. If flammable vapors enter through the flame arresting barrier they may burn as excess fuel in the burner area but the flame cannot flash back through the flame arrestor to the source of the vapors preventing fire and explosion. Older styles of water heaters without the FVIR Technology could be an ignition source for flammable vapors, possibly causing and explosion and fire if a flammable liquid was spilled nearby.
Clogged Flame Arrestor on the Bottom of the Water Heater
Burner Enhancement Kit
There are a lot of possible problems with water heaters many of them quite generic which will not be covered in this trouble shooting guide. The focus will be on problems specific to the Flame Guard and Flame Lock design water heaters.
Early models of the Flame Guard and Flame Lock Water Heaters had a specially designed thermocouple that included a one time use thermal fuse that was designed to trip when a taller than normal flame occurred. These thermocouples were unusual in that they had a thermal fuse in addition to the usual flame detection function and they had a left handed thread to prevent the substitution of a regular thermocouple. The availability of these unique thermocouples was limited to a limited supply at Lowes and through American Water Heaters. The poor supply of replacement thermocouples with a fee for shipping and handling from American Water Heaters resulted in a Class Action Suit and Settlement where owners were supplied with a “Enhanced Burner Assembly” which included a new combustion chamber door, pilot/thermocouple assembly, burner assembly, and a thermocouple adapter. The models included in this suit have a round sight glass in the burner door and have serial numbers beginning with “FG” and “FL” and were manufactured between 2000 and 2006. Water heaters manufactured after 2006 have the “Enhanced Burner Assembly” already installed and have a serial number starting with a “B” The Class Action Settlement Period ended June 28, 2008.
Thermocouple Adapter
The “Enhanced Burner Assembly” fixed the problem with the one time use thermocouple by using a resettable thermocouple which screwed into a thermocouple adapter. The thermocouple adapter screws into the left hand threads where the original thermally fused thermocouple screwed into the gas valve. Instead there is a reset button in the door of the burner assembly and 2 wires which connect to the thermocouple adapter.
FVIR Reset Button
The basic problem in most cases is a lack of combustion air caused by the screen of the air inlet on the bottom of the water heater. Frequent cleaning of this screen is required to avoid trouble. When the burner becomes starved for air the flame gets taller just like it would in an FVIR event and causes the sensor to trip. Some of the kits along the way also included a prefilter that wraps around the base of the water heater. If you have one of these keep it clean as well. Many people have luck making up a piece of pipe with an elbow on it to attach on the end of a vacuum cleaner hose to vacuum clean the screen under the water heater.
If cleaning the flame arrestor screen under the unit does not cure the problem there may be other problems relating to draft, insufficient combustion air, negative air pressure in the building or another problem in the unit that is best left to a licensed plumber.
If you have any questions or need additional help please leave a comment and I will reply.
I have just determined that I have a bad thermocouple on my 2003 Flame Lock water heater. I see that there is (was?) a conversion kit resulting from a class action, but the settlement period ended in 2008.
What are my options? Can I still obtain the left-hand thread thermocouple, or do I buy the conversion kit? I haven’t checked with Lowes yet as I just found the problem a half-hour ago.
Thanks for your help.
Lee
Hi Lee,
Sorry to hear you are having problems.
One of the options is to call American Water Heaters at their 1-800-999-9515 help line and wait for the burner kit to arrive.
Lowes does not have the thermocouple.
You may be able to find a plumber that has one but that is very unlikely.
Good Luck,
Redwood
GSW Series 6 Model – Model #G640S34FV-04 (Natural gas water heater, 40 US Gal. size)
- pilot ignites, but will not stay lit. How do I troubleshoot this?
Hi Shirley and Adam,
You will have to get the Instruction manual and trouble shooting guide from the manufacturers website and follow the steps. Sorry I can’t print the complete steps word for word here.
I got new enhancement kit by calling american water heater and after installing new pilot light did not stay. I called american water heater again and they sent me new gas valve/themostat. Lets see how long pilot stays up now. I believe that they are aware of the problems and sends kit overnight w/o any charge.
I tried to use reset button but when I pushes it, I did not fill that it was pushed in at all. how long we need to keep pushing it to be reset ?
Hi Sudesh,
Instruction manuals are available on the American Water Heaters website.
I believe that with the change out of the gas valve you pretty much have a BFG the instructions PDF has the lighting instructions on page 17.
The FG instructions may also have info for you on page 17
One of the key problems that probably triggered your problem is the air inlet screen under the unit clogging with dust and lint which caused a lack of combustion air into the burner. This typically results in a taller flame which tripped the thermal fuse in the original thermocouple which was replaced in the burner enhancement kit installation. Have you cleaned the air inlet? Without cleaning the air inlet your problems will continue and the air inlet will have to be regularly cleaned to prevent problems. Look for a tech bulletin covering cleaning the flame arrestor as well.
Yes, you are correct that they know there is a problem.
I hope this information helps you get your hot water again.
Thank you for posting your comments,
Redwood
Hi,
I believe Sudesh Patidar has already asked this question before, but I didn’t exactly see the answer that I was looking for. The question is how do you use the FVIR Reset Button? When I push the little white button in, it doesn’t feel like it’s being pushed in. I don’t want to put too much pressure on it as I am afraid that I might break it. I think someone said you have to push and hold it for 30 seconds or something to that effect. Could you shed some light on this? Thank you for your help!
Hi Jay,
The thermal switch should reset by pressing the button.
The FlameGuard BFG installation manual is available on the American Water Heaters website and will cover the instructions and troubleshooting for the water heaters that have the burner enhancement kit installed.
You can also call 1-800-999-9515 for help.
I hope this helps,
Redwood
For those that are having problems with the pilot light staying lit, I have arrived at a solution that may be worth investigation at your house. In studying the design of this water heater I focused on the pilot light and not the air inlet, my air inlet was clean not restricting airflow and was not a player in my pilot light fiasco. I went to my local Lowe’s and got 2 “C” retrofit kits for my water heater, no charge, and installed them. Each one would fix the problem and fire up to heat the water but was not a long term fix.
I did notice each time the main burner would go out it would cause the pilot light to move around a little and almost go out. I thought I was okay for each kit I put in (2) only to discover an hour later or whenever I checked later in the evening, the pilot light would be out!!!!! I decided to divide and conquer this @#$@%^% and win!!! I know the thermocouple acts as safety sensor to ensure the pilot light is present before the valve releases gas to the main burner to heat the water. The way it does this is by being placed next to the pilot light flame and being heated up enough to send 12+ mV back into the thermocouples adapter and into the gas valve. The presence of this voltage (must be at least 12 mV as the book says) tells the valve that its okay to send gas to the burner, the absence of this voltage tells the valve to stop all gas flow even to the pilot light because it assumes the pilot light is out. This is the reason why you have to hold the button down so long to light the pilot light; it has to heat up enough to send the 12mV.
I connected my multi-meter to the thermocouple to check it. I used alligator clips to put one lead on the copper line of the thermocouple and one lead on the outside silver connector (where the wire connects) to the thermocouple adapter connector. I pushed down the pilot light button and lit the pilot. The meter showed the output inching up the scale and just reaching 11.9 – 12, 12.1 mV. So I figured it was borderline and I needed a new kit. The last (3rd) kit I got from Lowe’s I checked the thermocouple in the store with my multi-meter and a fireplace lighter. When I put the flame on the TC it shot up past 12mV in 4-5 seconds, topping out at 21mV! However, when I put it in my water heater and lit the pilot it just inched up!!!! I also noticed as the pilot light flame moved around the voltage would sometimes drop below 12mV!!!! Eureka! The thermocouple was not close enough to the flame to stay hot enough to make a constant 12 mV!!! What added to this hypothesis was when the burner would go out and make the pilot almost go out, this was enough to make the thermocouple cool off and drop below 12mV and shut down gas flow! I took out the kit and bent the bracket that holds the pilot light tube and the thermocouple so they were closer together, now the pilot light only takes about 5-7 seconds to stay lit and it puts out about 21mV. When the flame dances around a little and the thermocouple cools a little it never drops below 16-17mV, not even close to the 12mV threshold!! If the pilot light still goes out for some reason, the thermocouple will still cool off and tell the valve to shut down so the safety factor is still there.
That’s the long version… Short version, bend the bracket so the thermocouple and pilot light are closer to each other!! Good luck!!
High J.
You are correct that the positioning of the thermocouple in the pilot flam is critical.
However too close can also be bad and trigger an FVIR shut down.
These are pretty tough units to work on.
Redwood
My Craftmaste heater is FG1H5040T3NOV – probably indicates manufacture around 2003. Went from functioning perfectly to complete failure to heat and inability to light pilot. Very glad to find your site as it seems “on point” and I feel I’m on the road to a solution. My hypothesis is that years of inattention, (my bad), resulted in a blockage of the air inlet screen. This caused a “tall flame event” and resulted in an opening of the one-time fuse in the special thermocouple. I gather the class action has ended but calling them, I have the number, may result in an upgraded kit coming to me – are they fussy about sending to the homeowner? I’ve looked at the manual, http://www.uscraftmaster.com/manuals/BFGmanual.pdf, and believe I will have no problem.
My only other hypothesis would be a completely clogged pilot tube and orifice but I consider this unlikely. Is there another possible explanation other than bad thermocouple, (understand this completely shuts the pilot and manifold tubes), or clogged pilot tube?
I found a wholsealer who purports to sell a very inexpensive thermocouple for the Flameguard units but doesn’t make much sense if mine is original and incorporates the special, one-time breaker.
Thanks in advance for any wisdom you can offer….
Hi Steve,
I believe they still send the kit out without any problems by what I have heard.
I believe they are not fussy at all about sending the kit to the homeowner in fact I’m shocked that they have such a liberal attitude about letting just anybody work on a gas appliance. I surprised they haven’t landed in court on that one yet!
If the flame arrestor was very dirty I’d say that is definitely the problem and the burner enhancement kit will take care of it.
Some have had gas valve problems as well.
Thanks for commenting,
Redwood
Looking at the parts close up, I see nothing that looks like the “one-time” fuse referenced in the manual and your webpage. Is it integral to the thermocouple assembly or is it in the valve control assembly?
I posted pictures to my website here. I have a device connected to my water heater that I don’t see on the representations of a typical water heater setup. Would appreciate if you could “name it”.
http://www.alexcomp.com/waterheater/waterheater.html
Hi Steve,
The initial “FG” version before the burner enhancement kit is installed has a double duty thermocouple that in addition to the pilot flame detection has a “one-time thermal fuse” built into the thermocouple. Once tripped the thermocouple had to be replaced and they were not readily available, which presented problems mainly the class action. American Water Heaters used a left handed thread to prevent installing a non fused conventional thermocouple.
Once the burner enhancement kit is installed in essence your “FG” becomes a “BFG” with the thermocouple still providing the tripping signal in the event of an “FVIR Event” or, clogged flame arrestor, but, the burner enhancement kit and the “BFG” models have a reset button which hopefully does the trick. Sometimes it doesn’t and moves on to other problems like the gas valve.
I hope this helps,
Redwood.
Houston. We have ignition! Lowes keeps the kit in stock. All you need is to supply model and serial number. The what is it part I referenced is a hot water recirculator pump – quick hot water to the tap. Thanks for the help.
Hi Steve,
Good to hear you have hot water again so quickly and easily.
I missed the “what is it part” in your last post yes that is a recirculation line and pump.
It is a good thing to have. Hopefully, your hot water lines are insulated instead of acting like a radiator heating your home.
Are there any controls on the recirculation system like a timer? Some newer recirculation systems are using occupancy sensors these days.
Thanks for posting,
Redwood
Thanks for your website, man. My water heater went out last night. I found your website at work today. Never worked on a water heater, but seemed simple enough. The thing is three years old so I was crossing my fingers hoping that it was a “B” model. It was. I had picked up a new thermocouple on way home for 7 bucks. Figured if I was going to work on it, I would replace it. I took the thing apart, cleaned the screen and burner, replaced the thermocouple, reassembled and fired it up. Nice blue flames and no sensor trip. Took about an hour. Saved a few hundred bucks. I will check the flame periodically from now on.
Hi Randy,
Glad to hear you got it working and the article helped you out.
I’ll keep my fingers crossed for you and hope it keeps on working.
Redwood
I ran across a related but different situation with one of these units.
I does have the thermocouple adaptor. I replaced the thermocouple. The unit would light and work for while. but after about an hour
the burner would just shut off even though it had not reached set point. And the pilot could not be re lit. I even tried an external
thermocouple heated from an external source and the pilot would not stay lit. On at least a couple of occasions, after sitting cold for
24 hours, the pilot would light normally. I am convinced that problem is the thermostat (gas valve). Is it possible that there is and
intermittent connection inside the valve? I am pretty sure this is the case. I checked the thermocouple adaptor with a meter and
it had continuity. I think this unit is about 5 or 6 years old.
I am not impressed with this unit!!
Yes I did check the combustion air screen. Yes it worked fine for five years!!
Hi Loyd,
I agree it probably is the gas valve that has gone bad.
They had a number of problems with the gas valve as well.
I would call American Water Heaters at their 1-800-999-9515 help line and see about getting parts.
Redwood