Gas Water Heater Question

My sister’s gas water heater has a pilot light that keeps going out and can’t be re-lit unless I wait a half hour of so. I believe the thermocouple may be faulty.

The water heater was installed in 2004 so it has the newer safety features built in including a spark igniter for the pilot light and there is no direct access to the burner compartment. There is a cover with a small window for viewing the pilot flame which is permanently attached with what appears to be rivets.

Any Dopers know how the thermocouple would be replaced on this type of water heater? Or if there are any other causes I should be looking for or if this type of water heater is repairable?

A new water heater is $350.00 plus tax.

I’ve not replaced the thermocouple in one of these. It is easy with an old style WH, though.

My heater has the same type of safety features. When the pilot light went out and wouldn’t stay lit I called a plumber to fix it. He just took the cover off and replaced the thermocouple and put the cover back on. Since then I have replaced it myself when it went out. On mine there are four screws that hold the cover on. I just have to make sure the fuzzy gasket isn’t damaged and make sure the thermocouple and wires stay in the grooves in the gasket when I put the cover back on. The plumber charged about $90 to replace it. It cost me about $7.00 to replace it myself.

They look to be about the same.

That is the most bizarre “safety” device I could ever hallucinate.

Ha-Ha - you need this flame and we’ll let you see it, but you can’t touch it! Is that really what is going on?

If so - find the tube (or wires) coming from the chamber and find the fittings connecting it to the heater. Unscrew fittings .Remove. Replace.
Obviously, turn off gas before…

Does it have the old Honeywell gas valve with the red knob on top to turn, hold, push, light, wait, turn fully? If so and it were my heater, those rivets would be gone!

Check the area around the heater - is something causing an intermittent draft which is knocking out the pilot?

I would have never guessed that some idiot would find a way to have BOTH an auto ignition system AND a pilot light in the same device. Incredible The disadvantages of both with the convenience of neither.

In mine, the auto ignites only the pilot light. You pump a knob until the pilot lights. I would imagine that it involves making money. :slight_smile:

What brand is it?

It might not be the thermocouple. In any event, in the newer WH manufacturers don’t really have a provision for replacing the thermocouple. The whole burner assembly gets swapped out.

Sometimes it’s clogged up combustion air holes, which will be on the side or bottom. Take out the burner assembly and clean out the combustion air perforations.

The burner assembly comes out pretty easily; one bolt on the gas valve, and the threaded thermocouple. The thermocouple might be a left hand thread. Be aware of that.

At 4 years old, this unit is likely still under warranty.

Part of the $90 you pay plumbers is for what they know. Their training took years and costed lots of money, and has an economic value. In addition, that plumbing business has lots of other legitimate costs beyond a $7 thermocouple. $90 looks to me to be cheap.

ETA Misread.

If it’s 2004 is probably out of warranty

I’m not the OP, but I have a similar water heater. It’s not an auto ignition system. You light the pilot by pushing the button on a sparker instead of holding a match to it. It’s similar to the way a lot of gas grills work.

Either y,our tank has a pilot light or it doesn’t.
I f yes, you have some sort of ignition, wait, engage cycle on the main gas valve controlling a small flame.
1° the thermocouple detects the heat of the flame, and give a hands up to the valve if warm though a small electrical current.

  • check the pilot light itself, a clean blue flame is best, check that the thermocouple is caressed by it
  • replace the themocouple, tighten firmly but gently the connection to the gas valve, do not kink the tube. Make sure that both the pilot light and thermocouple fixtures are in place and in good condition, if the thermocouple is not in the right position, it won’t function.
  • a 60 to 90 second delay is normal for some gas valves between re-tries, more is a bad sign. Either the thermocouple is shorting out, or the valve is shot

Start anyway with the themocouple, it’s cheap enough. If your valve is faulty, think about changing the whole rig, preferably for a new generation one without a pilot light (not the cheapest ones with battery powered ignition)

That’s actually a standing pilot unit, which has a spark plug-like means of lighting the pilot.

Automatic ignition systems are entirely different machines. Auto ignition systems have no pilot light, and essentially only create a pilot at the point the thermostats calls for heat. It’s an energy saving thing.

Instead of quoting everyone I’ll just answer your questions.

usedtobe: It has a conventional gas control with the “push and hold” manual pilot valve. Spark igniter is like what is used on gas grills.

raindog: Brand: Hotpoint, manufactured by Rheem (This is a Home Depot special.)
I’ll consider your advice in this post since when I looked at it yesterday the burner unit looks like it is replaced as an assembly.

I installed this water heater myself so replacing the entire unit is no big deal.

That’s weird.

The newer units in which the thermocouple is essentially fused (although with a little effort can be removed) to the burner assembly usually have a piezo spark lighter.

Many times it’s the combustion air. I’d check that and make sure there isn’t dust/ cobwebs etc.

I’ve lived places where a certified plumber had to attach his tag to a water heater at the curb or you were subject to inspection and fine. Only certified folks allowed to do it.

I used to do a lot of my own work until I discovered how expensive a mistake could be. I misdiagnosed a furnace problem as a bad burner when the problem was a plugged (by squirrels) chimney. When my kids got sick sleeping in the rooms near the chimney, I finally realized the problem and had to get a chimney sweep out on a below zero day to clean out the blockage. His $200 fee was worth every penny and then some.

I have this water heater working now. I removed the burner assembly (which is attached to the heater using tamperproof Torx screws-I have the correct tools to remove those), cleaned the main burner and pilot light, replaced the thermocouple (it may not have been the problem but changed it anyway), vacuumed the air intake vents and re installed the burner assembly. The gasket was still in good shape.


Cool. Thanks for the update.

I was afraid it sounded like you would need to replace the entire burner assembly.

Glad it wasn’t that screwed-up.

Enjoy lots of long hot showers!