Mystery pipe?

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

Some jurisdictions require the pressure relief to be piped outdoors. Sounds like this is what the OP is looking at.

Chip C Toronto

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.

Nope...PRV is on the side of the tank not on the CW supply line...

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. ^_^

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.

A pressure relief valve can be anywhere as long as it can "see" tank pressure and never be isolated. We have an indirect heater and the valve sits right on top.

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".....

If it is pressure only, yes. If temp and pressure, it needs to be in the top (portion) of the rank