# Water heater pilot problem Bradford White



## pellikkan (Aug 7, 2014)

Looking forward to an invigorating cold shower in the morning. NOT.


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## Nealtw (Jun 22, 2017)




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## pellikkan (Aug 7, 2014)

Hey, thanks very much for the video, I got a lot out of it.
But I wonder what would happen if the thermocouple device
was bad. i.e., would it emit zero, or maybe 1 or 2 mV?

If mine is bad, then it must produce a little bit at least in order
to run the status light that comes on. Could it be that there
is enough output to run the blinker but not enough to keep
the gas path open to the pilot? I don't know the mechanism
that keeps the gas path to pilot open. A relay or something?
Does anyone know how that part works??

I guess I'll go down there and take that assembly out to take
a look. Maybe like the video guy says , it could be just dirty contacts.


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## Nealtw (Jun 22, 2017)

Where I am the gas company will come out and check this kind of stuff. When they open their tool box the selection of thermocouples is the first thing you see.
I think they are cheap enough to say change it first just because. but your argument is a good one and puts some doubt in that being the problem.


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## pellikkan (Aug 7, 2014)

Well, I took out that burner assembly. I tested the thermocouple
with a candle flame and it read max over 150 mV. It seems kind of 
high compared with the video, esp with just a candle flame, vs blowtorch.

However, shouldn't maybe a test be done for milliamps as well??
After all, one can measure voltage on a dead 9V battery and it will still
measure 9.0 volts, but when a small load is added the voltage will dive
to zero because of no current. I tried reading amps on the most sensitive
meter setting but nothing would read, although I'm not sure if a milliamp
level voltage would create enough current to register. I also measured the
resistance of the Tcouple which read about only 3 ohms. 3 ohms is sort of a
heavy load, so maybe even a good thermocouple might be not able to
generate a measurable current. The resistance of the circuit board read
about 20 ohms, which is a bit of a load as well.

In other words, I'm still not convinced it is a good Tcouple because of the analogy
to a bad battery. That is, it seems to pose the question that if there is a good voltage reading on a Tcouple, is that an assurance that it is good?? Although I concede that a reading of zero volts would surely mean it is bad though.

Sorry, it is past my bedtime and I hope I'm not rambling more than a bit.


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## Nealtw (Jun 22, 2017)

Yeah, now you are above my pay grade. Hopefully some one with more knowledge will lend a hand


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## Colbyt (Jan 27, 2014)

If the thermocouple looks good I would suspect lint in the pilot orfice. Most are bell shaped. When removed and held in front of a strong light at your focus point the very tiny hole should appear as a round dot. 

This video is changing , not cleaning but it shows how to get to it.





They say you can't clean these and want to sell you a new one for about $10 or 6000 dollars a pound. I have found that a single bristle from a wire brush fits the NG hole nicely and will clean well.

If you house piping does not have a drip leg at the WH this would be a good time to add one as they help catch dust bunnies.

Sometimes it is ossification from the water and sulpher in the gas lines and you do have to replace it.


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## pellikkan (Aug 7, 2014)

Thanks everyone for the excellent help.

I got it going again finally. I bit the bullet and
coughed up a couple of hundred bucks for a 
so called 'kit', that included thermocouple, the
control valve and computer, and the lines going
from control valve for the pilot and burner. Didn't
include the burner plate thingy though.

The help desk at bradford white said it was probably
the control valve was the problem. Furthermore, the
desk guy at the plumbing supply said most folks often end
up coming back for the control valve after trying everything
else. So I just went with that. Works good so far and
I didn't blow up the block either.

Thanks again!, 
this is excellent forum BTW, thanks.


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## danpik (Sep 11, 2011)

These don't have thermocouples, they are power-pile generators. should be outputing ~750 Mv when hot.


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