Water Heater

Ultradog MN

Well-known Member
Location
Twin Cities
Water heater quit sometime Sat or Sunday.
Unit is about 4 years old.
Pilot light wont stay lit.
I replaced the thermocouple yesterday - Honeywell brand.
No Go.
Are thermocouples sometimes bad right out of the box?
Have replaced maybe 10 thermocouples in my life.
Pretty simple task. Never had a problem with one before.
This WH is the newfangled type with sealed combustion chamber and pizo lighter on it.
What are the 2 wires going into the combustion chamber for and could they be the problem?
What can I do before I have to call the repairman?
Thanks!

100_1866.jpg
 
Anything can be bad right out of the box, but I'd guess that the odds are against that being the case. On the other hand, if you can't get the information you need to get your WH going otherwise, another thermocouple is cheap, and you'll feel less bad about trying another one than you will about paying a repair person to find out that the problem is a bad original thermocouple and a bad replacement. Besides, if the 2nd replacement thermocouple fixes it, you get your money back from the 1st one. If it doesn't, you might not mind having one or two on hand if you've had to replace 10 in your life.

Good luck.

Stan
 
Does the pilot stay lit until the burner comes on?

If so, the spill over link may have melted, if it has one.

There will be a spring loaded closed damper in the bottom of the fire box. The spill link is a glass tube in the center bottom of the fire box that holds the damper open. If the flue doesn't draw properly or back drafts the fire, it overheats the link, it breaks and closes the damper, smothering the fire, and the pilot goes out.

I think you can buy the link, probably from a supplier that sells the heater.

Again, this all depends on the model, if it is so equipped.
 
I havn't repaired the type heater you have but logic would say the control must have a way of storing energy for the ignighter. That enegry could only be generated by the flame in similar fashion to thermocouples. If the ignighter repeatly attempts and fails to light the burner,stored energy would soon be exhausted. I would hold a gas match or torch on the thermocouple to see if burner would light. Hopefuly the flame will recharge the control and all is well. If burner lights and heats water but fails to reignight next cycle,the rechargable enegry source might be defective. The two wires leading to combustion chamber are likly part of the charging ciruit. What are they connected to and has it fell away from flame? I sure would like to see a scamatic of one those heaters,interesting arrangement.
 
Those 2 black and white wires are a safety switch. Think it was for overtemp if I remember right. I had to bypass (short across) mine a year or two ago. Has been fine since.
 
(quoted from post at 06:52:20 10/20/14) Water heater quit sometime Sat or Sunday.
Unit is about 4 years old.
Pilot light wont stay lit.
I replaced the thermocouple yesterday - Honeywell brand.
No Go.
Are thermocouples sometimes bad right out of the box?
Have replaced maybe 10 thermocouples in my life.
Pretty simple task. Never had a problem with one before.
This WH is the newfangled type with sealed combustion chamber and pizo lighter on it.
What are the 2 wires going into the combustion chamber for and could they be the problem?
What can I do before I have to call the repairman?
Thanks!
<img src="http://i61.photobucket.com/albums/h56/Ultradog/miscellaneous/100_1866.jpg">

Maybe the tip of the thermocouple is not all the way in the flame. I have a heater like you and mine had the same problem, i replaced 3 of them thermo's before i figured out why they would not work.
 
Will the pilot go out as soon as you release the knob, or does it quit at random times? If it quits after it's been lit for a while, it might not be the thermocouple. I had a heater in a rental that kept going out; the pilot was very weak. I bought a set of #60-#80 drills and a pin vise, then slightly opened the orifice on the pilot. Problem solved.

Is the unidentified device maybe a flame sensor to shut off gas if the main burner doesn't light?
 
I'm glad I confessed up front that I was guessing. After seeing DH's picture showing rest of control in place of the floor,I realized the ignighter is manual instead of automatic.
 
Well,
Between yesterday and today I've got about 2 1/2 hours laying on my side on the concrete floor fiddling with the bloody thing.
Pilot wont even light when I hold the button down now. It did yesterday but would go out as soon as I released the button.
I think I'm done with it.
Time to call in the big boys.

Thanks to all!
 
If it has im spark igniter it is one of those flammable gas safety water heaters. They have a glass vial inside that bursts or breaks if the combustion chamber gets too hot. When that breaks it shuts off the air supp,ly to the combustion area. You can take a bolt about an inch long and put it where the glass vial used to be. Not recommended by the safety police but is in essence no different than an older style water heater. There are some you tube videos on doing it. The first one you come across like that is a head scratcer. Basically you push down on a lever way in the back of the combustion chamber. Once you figure out how to hold that air damper open, you will say oh ya, now I get it. A new water heater will have the same safety crap on it so you might as well figure it out now. Good luck.
 
I'm no expert and I don't know what those two wires do but my water heater had the same problem a few years ago. I took a penny out of my pocket and laid it across those two wires so they were looped together and it worked. I forgot about it and it ran that way for over a year. A guy I work with was having the same problem and I told him about it and he said that it worked for him also. I think he changed that piece out when he found that to be the problem. Deluxe
 
I hate all these new water heaters. In my service of them over the last 10 years have found several problems. The biggest issue people seem to have it the pilot will stay lit and allow the burner to cycle until it heats up and when the burner shuts off it snuffs the pilot out with it. When this happens, it is not getting enough fresh air for combustion and although most everyone will tell you not to do this, I had a factory rep both with AO Smith and Reliance tell me when this happens to take the 2 or 4 screws holding the inter sealed cover on out and remove that cover and throw it away. That is what I do 99 percent of the time.
Other thing mentioned is the thermocouple may not be in far enough to sense the flame and that will cause the pilot to go out as soon as you let up on button.
Other thing is bypass the sensor with two wires going to it as if it is bad it will act the same as if the thermocouple is bad or not pushed in far enough.
last but not least, some or a lot of the thermocouples have a little diode built in thermocouple, you do not need one of those expensive thermocouples, as a regular 10-12 dollar thermocouple will work as it always have.
I think this about covers it and as long as you are not storing any flammables ie. oil base paint, lawn mower gas cans etc. you do not need all that sealed up where it can not breath and burn clean. Both reps would not give me there name because they said they would be fired for giving me that info, but the first heater I was having trouble with was 6 months old after they came out with the sealed combustion. and 40 miles from the office and can not tell you how many factory people and things they suggested I try before I got ahold of the one who advised to throw that inter cover away and your troubles will go away. He was so right!!. Hope some of this helps.
 

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