Water Heater Pilot Turns Off After Water Heats Up?

Question

I have already replaced the thermocouple...

Answer 1

Most commonly I have found that to be the result of a weak, dirty, pilot. When the main shuts off there is a strong draft and it blows out the pilot.



This is more of a problem recently because for energy efficiency they are using smaller, weaker pilot that are more sensitive to this. Some brands even had a recall and they sent out a new pilot that had a bigger hood to protect against blowing out. But sometimes cleaning the pilot orifice will solve it though.



I take a piece of braided wire stripped back some and use it like a miniature wire brush to clean it. The hole in the orifice is smaller than a pin hole.



The second, less common problem is that sometimes the main burner gets warped and the main flame encompasses the pilot. So while burning the pilot is out but the main flame is keeping the thermocouple warm then when the main goes out the pilot is out. That is usually solved by checking to see if the main burner is level and correcting it if is it not.



Good Luck.



And PS, if you watch it burning and are fooling with it, on and off, don't put your face directly in front of it, look from the side and back some because if it misfires you don't want to lose your eyebrows. I have seen more than one tech who had their eyebrows "trimmed" and have come close to it myself.

Answer 2

Sounds like the gas thermostat/control valve is going bad and needs to be replaced. If the new thermocouple didn't help, then that's about the only thing left that you can replace. There's no internal repairs to be done to them. If you do decide to replace it, be sure to check for which way the burner supply line nut turns as it connects into the bottom. Some are right handed, some are left handed. It's not fun to get a new control and then find out it won't work because the burner nut is the wrong thread. And, for John M, gas water heaters, unless they're powervented, don't even use electricity, let alone 220 Volts.

Answer 3

When you first light the pilot, don't turn the control to 'ON'. Check the pilot flame. If it stays lit, continue. If not, the control valve needs replacing. If the thermocouple is properly adjusted (in the flame of the pilot light), and the flame is very small, use a small metallic object (table knife handle will do) to GENTLY tap on the gas line from the control valve to the pilot light. Tap close to the control valve, GENTLY. Dirt in the pilot orifice causes the low flame, and 99% of the time this GENTLY tapping will clean it out. If you are watching the pilot while tapping, the flame will turn yellow, and grow a little each time you tap GENTLY. When the pilot flame is too small, the main flame can blow the pilot out when it shuts off.

Answer 4

call your local gas company and ask them if you have service call out ins. with your supplier.



it sounds like the thermocouple is not holding and the bi mat. metal is weak or bent. you can do a electrical check if you understand electricity, but it is 220 vac, and 30 amps or higher, so I would advise it if your not sure.

Answer 5

sounds like it is clogged. you can get it cleaned or replaced or just junk the hole thing. (if you have the money and it's more than 10 years old go with #3. tank-less are very nice.)

Answer 6

sounds like a faulty safety sensor

Answer 7

That is normal, a pilot light must always be lit.