gas water heater and sidearm advice

[dodgetech]

hi i have a central boiler 6048 and sidearm for dhw when it got really cold out last week i turned the temp on the boiler up to 192 now i noticed the gas water heater pilot is out and i cant relight.
i'm thinking that the higher temps locked out the gas valve. does anybody know if there is a different style or adjustable gas valve i can get. there isn;t any type of reset on the valve,so i assume it is shot,but i dont want to keep buying these valves to keep it running. we hooked the mixing valve up backwards so until i switch that around the gas backup helps. thanks

 

[Eric Johnson]

My guess is that the high temps simply tripped the breaker on the hot water heater. Find the thermostat and push the reset button in--hard--with a screwdriver. If a gas WH is like an electric WH (I've owned both, but forget how the gas model worked), there's a temp-sensitive breaker that will cut the power to the burner when the water temp exceeds the preset.

I doubt that anything is shot--just in "safe" mode.

 

[webie]

Guys I did this once and ran mine up too about 190 . I ended up replaceing the burner control , It seems these have a one time fail safe that in case you have arunaway water heater it pops something inside the control to shut off the gas . I tried changeing 2 different thermo couplers and couldnt get the pilot to stay lit and after I talked to AO smith the water heater maker and told them what happened they told me this .
Sorry

 

[webie]

On the top of my control there is even a tag that says this control has an automatic gas shut off for high water temperature and is one time use and is non resetable .

 

[in hot water]

ECO (energy cutout), is built into the valve. 190 °F is pretty darn hot for any glass lined tank, most manufacturers recommend 180 °F max. on glass lined storage, indirect and solar tanks.

You also have, or should have a 210 °F T&P valve in the tank. If it pops be sure it is piped to a floor drain or you could have some serious water damage.

If the ECO at the bottom of the tank hit 190 °F the top where the relief is located could be much hotter, dangerously close to that 210 °F That relief valve is also a one time on temperature release.

That is why it is important that the probe of the relief valve be in the top 6" of the tank, top or side. Never move it out on a tee without an extended probe.

Might be a good idea to check the function of that relief valve, they do stick from time to time. An overheated tank without an operating pressure relief valve can make for a BIG boom. A new T&P is probably under 20 bucks, very cheap insurance.

Look into piping a bypass or some sort of high temperature protection mechanism.

hr

 

[Eric Johnson]

Thanks for your safety tips and advice, hotrod. It's something DIY enthusiasts tend to forget/ignore from time to time, and it's always good to get a reality check from a pro with experience. Heck, at first I thought those pics were from Haiti.

 

[Gooserider]

At least on our gas DHW heater, there is no breaker - or any other electrical hookup - just the gas valve with it's thermocouple sensor for the pilot light... Far as I know it doesn't have any sort of thermal cutout, or if it does, it is self resetting... We had a defective valve when the heater was first installed, it would stick on until the T&P blew, and apparently the steam from that was enough to put out the burner, and the tank would then cool back down. I would find the pilot was out, and that I'd had a flood, but was always able to relight the pilot... Took me a while to figure out what was happening, at first I thought it was a weak T&P, and replaced it with new, then I caught the thing in the middle of the cycle... Our usual plumber was on vacation, so I called the heater Co. and they sent a guy out from one of their local service companies - who swapped out the valve with a new one, and left me with a gas LEAK :grrr: in the line from the valve to the main burner... Had to call him in for a second trip to properly tighten the connections....

Gooserider

 

[in hot water]

The ECO is built into most, if not all gas aquastats for water heaters. If you remove the aquastat from the tank it is a metal disc with a few wires on the back, a fuse that blows on temperature, really. The thermocouple generates the current that holds the pilot button down, the ECO interupts that circuit on overheat.

Not sure how accurate they are calibrated and if the tank is heated with an external hx the ECO is near the bottom and may not see the hottest temperature. Just depends on how the HX is piped and pumped to the tank.The T&P is an additional temperature overlimit device, so you have the aquastat the ECO and the "T" side of the T&P for overheat protection.

Yet I have seen all of them fail and the tank foes towards the moon. Watts has some good video of this on their website also.

Stay safe is the point when you blend water, pressure, heat, electricity, fire, by products of combustion, etc they is the need to be advised on safeties and their operation.

Same with combustion air requirements, CO is a silent killer.

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