Hot water heater temp variation

[TomFOhio]

If you fire it up and the burner burns good then most likely its the control valve. Yours isn't anything special. You got the
thermocouple, pilot tube and burner tube. You could take it out and take it to a supply house and get something equivalent.
That bulb that goes into the tank is probably not sensing the water correctly. Maybe while you have it out you can make sure
its cleaned out inside the tank. Good Luck...

 

[Ron6519]

No there’s not. The thermostat is located inside the gas control. The control is considered the thermostat.

It’s not serviceable.

There was a guy killed here a few years ago tinkering with his water heater control after it continually malfunctioned. It was an AO Smith brand. Not sure what brand control was on it. Anyone that interested can read about it.

Proceed at your own risk.

This one is a White Rodgers model 37C73U 642. Available for around $100. Sort of screws in like a light bulb. Seems it gets an insulating slurry of calcium carbonate on it that insulates the probe. Could just need a cleaning. I remember when I replaced the anodes it was coated with this sediment.
I don't find most plumbing to be too complicated. This would fit into that category.
On Long Island a few years ago, a plumber was working on a propane leak in a basement. House blew up, killing him, the real estate agent and an 18-month-old.
Seems knowing what you're doing has a wide translation.

 

[Twowaxhack]

This one is a White Rodgers model 37C73U 642. Available for around $100. Sort of screws in like a light bulb. Seems it gets an insulating slurry of calcium carbonate on it that insulates the probe. Could just need a cleaning. I remember when I replaced the anodes it was coated with this sediment.
I don't find most plumbing to be too complicated. This would fit into that category.
On Long Island a few years ago, a plumber was working on a propane leak in a basement. House blew up, killing him, the real estate agent and an 18-month-old.
Seems knowing what you're doing has a wide translation.

Its your house, as far as I’m concerned you’re more than welcome to do what you want.

I’m certainly not trying to stop you.

At least now you know the proper names to call the parts. That’s a start.

Good luck to you, have fun with it.

 

[Ron6519]

If you fire it up and the burner burns good then most likely its the control valve. Yours isn't anything special. You got the
thermocouple, pilot tube and burner tube. You could take it out and take it to a supply house and get something equivalent.
That bulb that goes into the tank is probably not sensing the water correctly. Maybe while you have it out you can make sure
its cleaned out inside the tank. Good Luck...

Thanks, for the info. The White Rodgers model 37C3U 642 is still available around here. Replacing the anode a few years ago I saw a milky white slurry coating the rod. Probably that's what's coating the probe.
Other than that, the water heater works fine, so I'll drain the tank and take a look. Good time to evaluate the tanks condition with the scope.
I've heard recently that it might be time to replace the unit.

 

[Ron6519]

Its your house, as far as I’m concerned you’re more than welcome to do what you want.

I’m certainly not trying to stop you.

At least now you know the proper names to call the parts. That’s a start.

Good luck to you, have fun with it.

Every profession has its own terminology and language. Sometime learning the terms is half the battle.
Thanks for the help.

 

[Twowaxhack]

The water heater gas controls typically had a plastic covering over the probe that extends into the tank. This prevents a build up of minerals.

When you get yours out of the tank, post some pics of it.

 

[MrInfoPhilly]

i think the O.P. is highly underestimating the danger of repairing a gas control on a water heater., If you install it yourself., why not just replace it? you obviously don't value your time., the tank appears to be developing leaks...

 

[MrInfoPhilly]

Water heater Explosion

 

[Ron6519]

i think the O.P. is highly underestimating the danger of repairing a gas control on a water heater., If you install it yourself., why not just replace it? you obviously don't value your time., the tank appears to be developing leaks...

I'm retired. I have all the time in the world.
The tank has no leaks. I don't know how you've perceived the "developing" aspect.
I've repaired both the boiler and the water heater in the past. Thermo couplers in the water heater and vent dampers in the boiler. Installed gas ovens and gas cooktops. So far nothing has leaked, much less blown up. If need be, I'll install a new water heater, maybe a tankless one.
But I did enjoy the video. I think that's the way Cape Canaveral was conceived, sans the flooring.