I have a Rheem water heater, NG fuel, flue vented, has been reliable for 3 years.

Just experienced the 2nd flameout in about a week. When I relit the pilot last time, everything seemed normal. Now that it went out again, I'm wondering what I should do next?

Edit More Info:

I searched YouTube and learned how to probe the thermopile wire harness. I was able to measure 670 mV on my water heater, however I noticed that I had to click the sparker every minute or so as the thermopile heated up.

For an extra check, I reconnected the thermopile, turned off the lights in the room, and from the sight glass I can see the pilot stays lit only if I keep the control button completely pressed. The LED indication is normal, but if I take my finger off the button for even an instant, the pilot goes out.

So far I haven't been able to get a successful relight.


2 Answers 2


Over years of usage Thermocouple get dirty.

It does not deliver the signal of "Flame present" and the system shuts down.

Sometimes just cleaning it does the trick.

If not, replace it and yes it is a DIY job.

However there are other sensors that must work and could be the reason for system shutdown. Best would be to check the manual.

  • I was able to verify the thermopile is working. Commented Mar 13 at 14:58
  • @RobertChapin great work on TC, on to the next sensor, like the overheat protection
    – Traveler
    Commented Mar 13 at 17:49

Defective Honeywell gas valve.

Either pull the entire burner assembly and find a replacement, or get a new appliance.

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