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gas water heater thermocouple

New home owner 6 months ago i had plummer come in because the water heater would stay lit, the day i moved! Was working during the inspection.


After a cold week, we came back and i tried to get some hot water, and it wasn't working. I went to check my gas water heater and saw i had no flame. Now watching the plummer before, he replaced the thermocoupler and I know he had a hard time getting it to work because i could hear him working that torch to light it.


Now i tried to light it when it is 20 degrees outside and who knows how long it has been out. I turn it to vacation mode, turn the valve to pilot, press the red button, light it was long match, hold it for 60 seconds, let go of the red button and it goes out. I did this for about 15 minutes. Did the thermocouple go bad again? Is it something else? Was the plummer using the torch to get the thermocoupler heated up so it stays one? Is it suppose to get red in order to stay lit? I have a nice blue flame but it won't hold. I tapped it a little since i read that it could have some residue on it. Wondering if I should scrape it with a brush.


So should i replace it?

Look into whatselse could be the issue?

Take it out and frush it off, clean it off?

Do i need to get it real hot to stay on, like use a torch like the plummer did.

Looks like an easy job and a cheap one from all the videos i have watched. Just hate to find out it is somethingelse.


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Posted 2013-02-11T16:42:36+0000  by Auxiliary Auxiliary

the plan is to get rid of it and get an on demand hot water heateron my current water heater had a 6 year warranty on it and is 10 years old now. 


So I made a service call and it was resolve in 2 minutes by heating up thermocouple with the torch. i understand how the thermocouple works and he said that it was getting bit enough for it to stay on. it was very cold here so the little flame wasn't doing the justice. Maybe if I worked it more it would of stayed on. I think I said the pilot light pipe is pinched though it has a nice size flame come out. Maybe if I had that replaced I could of done it, but HD disnt have that part In stock. The call cost me $50. 

Best Answer

Posted 2013-02-17T19:55:21+0000  by Auxiliary

Hi Auxiliary,


After the thermocouple the most common cause of pilot light failure is carbon on the pilot burner. As time goes by carbon deposits build up on the pilot burn tip.


These deposits reduce the gas flow through the burner and thus the pilot does not receive enough gas to stay lit and is easily blown out.


The plumbers torch may have burned away some of the carbon when he worked on the pilot.


By the way using a torch to light a pilot is Not Recommended!  It’s a good way to blow up your home, and shorten your life.


The answer is to use a stiff bristle brush and remove the carbon deposits from the pilot burner. Try it with the burner installed. A firm bristle tooth brush works well.


If this is not effective you may have to remove the pilot burner and clean it.


Once you have cleaned the pilot burner, try relighting the pilot. This often solves the problem.


Don’t forget to return the control from vacation back to the normal setting.



Posted 2013-02-11T18:08:43+0000  by Mike_HD_OC

i used a nylon Brush and cleaned it , though didn't seemed that it was dirty to me. Tried lightning it again and the pilot light went out. 


Thermocoulpe I don't mind taking it out but pilot I'm not comfortable with that part. 

Was thinking of using a voltage meter to see if the thermocouple is working. I have  one , but I don't know how to use the dial. 

Posted 2013-02-12T04:02:51+0000  by Auxiliary

let me ask you this.  When you look at your pilot assembly is there only the pilot flame hood and a thermocouple sticking up or is there a third think sticking out that is about 3/8" diameter.  If there is that third thing that is called the powerpile or mV generator and i would replace it.  If there is only the 2 pieces i would replace the thermocouple yourself and clean the contact point on the gas valve as well.  If neither of those two things work you are looking at a new gas valve.

Posted 2013-02-12T16:30:18+0000  by joshcameron


Hi Auxiliary,


Sounds like the gas control valve may be the problem. How old is the water heater? It may be time to just replace it.


Gas control valves usually last the life of the water heater. If it's failing then other problems are not far behind. 


New water heaters are much more efficient than those sold 10-15 years ago.


You might try a new gas control valve; however I think now is the time to bite the bullet and replace the water heater.



Posted 2013-02-14T18:07:36+0000  by Mike_HD_OC
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