# three thermocouples in a year



## klempner (Mar 4, 2011)

Water heater, maybe 15 years old. pilot out, replaced thermocouple. all good, except maybe half a year later, same thing. relights, but goes out as soon as i release override. replaced thermocouple again, stays lit. very short lifespan for a thermocouple, but should be good now. 6 months later, same thing. thermocouple again fixes the problem. if it was the control valve, curious why the thermocouple would solve the problem. but why would a thermocouple go bad that quickly? and then again, roughly same interval again? does a new thermocouple somehow temporarily "trick" a defective/dying control valve? did i get a batch of bad thermocouples?

yes, tip fully inserted into housing. exactly where it's supposed to be. yes, nut tight at control valve.

no, i didn't charge for the last two trips out.

????


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## Plumbergeek (Aug 16, 2010)

Pilot flame too high causing premature failure? Gas valve needs adjustment?


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## OpenSights (Mar 23, 2015)

10-12 years, after that we replace. No reason for our customers to throw good money at a bad problem. 

I still see '50's heaters working just fine, but the manufacturers don't make money if their products last forever so they make them with a short lifespan. Add the federal government to the mix and our cost jumps $200. Prices are going rise again soon. My supply house just added 140 heaters to every location in anticipation. I don't think that added stock will help us when the price jumps.


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## Plumbergeek (Aug 16, 2010)

I agree, if heater is that old it needs replacing.


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## klempner (Mar 4, 2011)

i agree, water heater too old to replace control valve, but it's hard to condemn it over just a thermocouple. and it's hard to think it could be anything other than the thermocouple, since it immediately solves the problem for another six months. it really sounds like thermocouple is defective, except that i've never seen thermocouples be defective like that. the customer isnt throwing any money at it at the moment, as I'm eating the trips and the thermocouples. the first thermocouple went 14 years. now, one year later, it's suddenly on its fourth. if it were electronic, i would be very suspicious of the control valve. before i change the thermocouple each time, I try relighting it and it immediately goes out. then, i put a new thermocouple, and immediately, all good. maybe there is something in the control valve that resets when the thermocouple is removed and reconnected, but it sure seems like the new thermocouple is what is making all the difference. I'm going to temporarily sideline all my thermocouples on hand, and switch brands and see what happens.


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## Tommy plumber (Feb 19, 2010)

Probably not the gas. Probably not the gas control valve. Probably not faulty installation (since after you replaced the thermocouple the W/H operated for months). That leaves only the thermocouple itself, in my opinion.

Perhaps it was a cheaper brand, or made overseas from inferior metals.

In my opinion, don't eat any more warranty repairs on this W/H. Tell your customer if it fails again, it is time to replace the unit.


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## 5onthefloor (Sep 13, 2017)

Yes it seems like it might be time to replace. They should at least see you gave it your best and did not try to just shove a new install down their throats. Plus they'll be glad to have the latest tech if you do replace...









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## klempner (Mar 4, 2011)

Honeywell brand thermocouple. made in mexico, it says.


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## 5onthefloor (Sep 13, 2017)

Keep us posted!

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## Sipp (Jul 14, 2016)

Most likely it's a weak magnet in the gas control valve. A brand new thermocouple produces enough voltage hold the magnet in place. As the t-couple ages, the voltage drops off a little. Suddenly you have pilot outages. 

Easy test to do on the older mechanical valves, won't work on the Honeywell electronic valves.
-With a new t-couple installed, light the pilot and let it burn for about 10 minutes to get a good heat soak into the t-couple. After 10 minutes, turn the "On-Off-Pilot" knob to "Off". Yes, the pilot flame will go out. Time how many seconds it takes for you to hear the pilot valve snap shut. A good valve with a new t-couple will take longer then 45 seconds. A bad valve will close in under 45 seconds.


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## tanklessheater (Sep 25, 2017)

as much as we want them not to be replace, replacement should be consider.. 15 years must be enough. .


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