Mystery pipe?

City water can be shut off, making the tank a closed system. Then simply heating cold water can generate enough pressure to pop the relief valve. I found that out by experience after closing the meter valve to make a repair. jsw

The relief valve on our HWS cracks every sunny day (solar system), old gas system used to as well.

Check out the Mythbusters video on what a HWS explosion can do - quite impressive & destructive even if it is enhanced by the Jamie's.

new hot water tanks come with a temp pressure valve pre installed, the outlet should go to the floor to prevent a scald hazard if someone happens to be walking by when it operates

Yes, that tank and water explosion was a sight to behold. IIRC they removed the TP valve, and deliberately blew it up. Took much longer than they expected.

Christopher A. Young Learn more about Jesus

Check out the Mythbusters video on what a HWS explosion can do - quite impressive & destructive even if it is enhanced by the Jamie's.

Why do you have a HW heater? Does your WH not make CW hot enough?

If you heat hot water, doesn't it boil? So a hot water heater would be a boiler? ^_^

TDD

Why would one heat hot water?

To get steam you big silly thing. ^_^

TDD

That would depend on how hot you heat the hot water.

In the average house you probably have an 80 - 90 degree range before your HWH becomes a boiler, although we need probably need to factor pressure (and the PRV) into the equation.

To keep it hot?

I remember Myth Busters removing the T&P valve and plugging to hole in an electric water heater and building a little test house, filling the heater, turning on the power and watching the thing take off like a rocket blowing up the little house. ^_^

TDD

A friend's boyhood home had a water heater explosion early one Sunday morning. It lifted all the floor boards from the joists, most of the joists from the foundation, and the floorboards from the upstairs floor as well as blowing out all the windows and lifting the roof. Apparently it took several weeks to get the old farm-house livable after. Neighbours a few farms away felt the shock as well as hearing the boom.

My guess is that it is the prolly regulator..

new hot water tanks come with a temp pressure valve pre installed, the outlet should go to the floor to prevent a scald hazard if someone happens to be walking by when it operates ===================================================

OK, since my HWH is a Kenmore, it of course has this valve built in to the heater itself.

Is what Jim was talking about how they did it in the old days? If so, then I can just remove that piping?

Now I know what those long tubes are for! I guess I should put one on.... :)

That would be "proly".....

What is a prolly regulator????

The old days? I replaced my water heater a year ago. jsw

Some new fangled safety devices are a good thing?

Christopher A. Young Learn more about Jesus

A friend's boyhood home had a water heater explosion early one Sunday morning. It lifted all the floor boards from the joists, most of the joists from the foundation, and the floorboards from the upstairs floor as well as blowing out all the windows and lifting the roof. Apparently it took several weeks to get the old farm-house livable after. Neighbours a few farms away felt the shock as well as hearing the boom.

What did you pay? I think I'm on borrowed time... :(

So you have a relief thingy on the LINE, and not on the heater itself?