A motorized ball valve to shutoff water to my house

[jteneyck]

I bet your insurance company would entertain a discount on your homeowners insurance for having installed this. I think I read once that damage from flooding due to bursting pipes/hoses dwarfed their other claims.

I'm pretty sure you are right that water damage dwarfs all others when it comes to insurance claims.  Several people I know have had burst pipes in the winter, a washing machine hose blow, an ice maker line pop off, a dishwasher drain hose rupture, tub overflow, and I think others. 

I'll have to ask my insurance company if there are any discounts for doing this.  I'll bet if there is it's only for a passive system, one that doesn't rely on a human remembering to turn it on/off. 

John

[geek2me]

It's a temperature and pressure relief valve. It doesn't know what is on the loaded side. If any substance exerts a pressure greater than 125 psi, it opens. Air, water or fairy dust, if the pressure exceeds 125 psi, it opens.

Sorry, but that is not correct.  The common T&P valves are designed for water, and you can confirm this by reading the data sheet.  They will not function properly with air pressure, that requires a different type of valve, the physics of air pressure are quite different.

[geek2me]

Both documents you provided stated that an explosion required the failure of two safety controls, not a loss in supply water.

If you are curious, might want to read them again, since they clearly show the loss of supply water as a proximate cause.

[jteneyck]

If you are curious, might want to read them again, since they clearly show the loss of supply water as a proximate cause.

I read them again, and don't see anything to support your statement.  

But anyway, you are wrong about T/P relief valves.  They open both on over pressure and over temperature.   Read this Link  

John

[blackhat]

The pressure relief function is a simple spring loaded disc. When the force on the bottom of the disc exceeds the force exerted by the spring, the disc lifts and pressure is vented until the spring force pushes it closed again. If you want to talk about flow rates or time pressure curves or design capacities that is a different conversation. If maintained, the T&P valve supplied with a water heater is capable of preventing a catastrophic explosion of the pressure vessel. Period.

[woodhead]

If you are curious, might want to read them again, since they clearly show the loss of supply water as a proximate cause.

...and both had the relief portion of the safety valve blocked or omitted!



Al

[EdL]

Check valves were installed here when we got water meters......2-3 months later, they removed every last one, to many problems & complaints.

When they stopped to remove mine, I handed it to them. I removed it less than a week after installation.




Ed

[geek2me]

I read them again, and don't see anything to support your statement.  

But anyway, you are wrong about T/P relief valves.  They open both on over pressure and over temperature.   Read this Link  

John

Well, you are certainly entitled to your opinions, I'm just sharing the facts so people can make informed choices.

Not sure what you misunderstood about my post, as your link shows the facts I shared regarding T/P valves are correct ("Protects water heaters from excessive water temperatures and pressure").  Again, the key point is they are designed for water pressure and temperature and won't work correctly with air or steam.

[geek2me]

If maintained, the T&P valve supplied with a water heater is capable of preventing a catastrophic explosion of the pressure vessel.

No disagreement - the point that you got wrong is the claim that the valve will work correctly with anything other than water.

Simple experiment to prove the point.  Fill two balloons, one with water and one with air, to the same size.  Both have the same pressure, which is shown by them being the same size.  Poke both balloons with a pin - the water-filled balloon will collapse, the air-filled balloon will explode.

Air is also a good thermal insulator, which is why the temperature part of the valve will not work correctly with air, for example.

[blackhat]

I got nothing wrong.  Show me a catastrophic failure of a water heater with a properly functioning T&P valve.  Your parlor trick balloon example is invalid unless your balloon is steel and the release is close to the material failure point. If you repeat that example with less pressure, the result is 2 leaks and no explosions.