Cal

I've seen several of them ,, and this is EXACTLY what happens !

Yet i'm having a lot of problems with expansion tanks ,, they are seeming to fail more regularly .

What about these relief valves you are talking about Pro T ??

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"The unforgivable crime is soft hitting. Do not hit at all if it can be avoided; but never hit softly."

TheMaster

Heres a relief valve that adjustable.......its not the same one protect uses but read the application standards and how the valves works. I still maintain that the relief valves protect uses are not reliable in controlling thermal exspansion reliably. It could be too slow to act or get clogged. be sure to read the entire page of this link....
http://straval.com/catlist-relief-va...hreaded-rvi-20
Here I copied it:
Applications

This safety relief valve can be used for relieving pressures and maintaining upstream line pressures to a specific set pressure. Pressure relief valve can also be used for bypassing fluids or gases. Only strained or filtered liquids are recommended. When liquids contain debris or other solid matter which might cause the valve seat not to close properly with this type of pressure relief valve, a low-pressure strainer with a fine wire mesh should be installed before the inlet of the valve. Simplex basket strainers or low-pressure filters can be purchased from Stra-Val. This is a diaphragm low-pressure valve which is used where accurate set pressures must be maintained. The large diaphragm area compared to a piston pressure relief valve produces much more accurate pressure control with very low hysteresis between opening and closing pressures. See available orifice sizes and flow Cv below.
For higher relief pressures see models RVC05, RVT05




Options

See pricing Table to select available options


Principle of Operation

This is a diaphragm and spring type relief valve where the spring constantly opposes the pressure acting against the diaphragm which seals off the inlet port from the outlet port at the valve seat. The desired relief or bypass pressure is achieved by compressing the spring until the spring force is adequate to balance the pressure force acting against the diaphragm. When the inlet pressure exceeds the set pressure, the diaphragm will open to relieve and bypass the excess pressure.The valve will operate in a vertical orientation as illustrated, horizontal, or any other orientation.
Although the ports are inline, this is not a "through flow" model where flow continuously passes through the valve. If this valve were to be installed in a flow line, it would shut off flow to the line completely and open only when the set pressure is exceeded. This valve is typically mounted to a device to be protected such as a tank or other pressure containing device. If a flow stream needs to be protected from overpressure, then the valve is mounted on the side of a Tee, or at the end of a line branch where it will pass excess flow only when the valve opens. The outlet port of the valve is usually piped to a drain or discharged directly to atmosphere only if the liquid or gas is safe to be discharged without injuring personnel or damaging equipment nearby . For a true "through flow" model, see our model RVT05 which is a piston type that has three ports.

Ron

I have never seen them here, heck every single resident I go to I never ever see an expansion tank, in commercial yes. I guess it's an Oregon thing, no one puts them in and there is no problems around here.

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Stephen Hawking: If the government is covering up knowledge of Aliens, they are doing a better job of it then they do at anything else.

TheMaster

You guys may not have closed systems. If the systems closed you will have problems. A system cant be closed unless all leaks are repaired,so if they have a dripping faucet its not closed. Somtimes the customer will not have any issues until you repair all the leaks.....then boom the pressure goes up when the water heater kicks on.

Ron

We have closed systems here just as you all do, lots of PRV's valve in the grounds. On new homes as well they are there.

__________________
Stephen Hawking: If the government is covering up knowledge of Aliens, they are doing a better job of it then they do at anything else.

TheMaster

Here a test Ron. Make sure you have no leaks in your house or drips. Run about 20%-30 percent of your hot water out of the tank and make sure it energizes or fires off. Attach a gauge to the drain valve....now turn your stop valve off on the cold side of the water heater. Watch the gauge......if the system is closed the gauge will rise slowly and then almost or completely stop for a few minutes....then boom it go way up. Try it out.

Cal

We had all talked before about the 3/4" ball valve with a pressure relief port . I think it's a Watts .

Anyone use these ??

__________________
"The unforgivable crime is soft hitting. Do not hit at all if it can be avoided; but never hit softly."

Cal

Never mind ,,, found em ! Watts BRV

__________________
"The unforgivable crime is soft hitting. Do not hit at all if it can be avoided; but never hit softly."

TheMaster

A few plumbers here that do new houses will not use those...they said they were getting callbacks for the valves continually running. The watts ballvalve with exp port. Maybe they got a bad batch and maybe changes have been made to them I dunno. I have a few in stock but haven't used them yet for the reason I stated above. I'd rather have a tank fail 2 years after I install it than a valve 2 months after I install it.

Redwood

I dunno if its the expansion tanks I'm using or, the way I set them up but I don't see many failures.

Amtrol Therm~X~Trol tanks are lined to prevent corrosion of the steel tank and the bladder pre~charge should be set to match the pressure of the system. Proper precharge eliminates excessive bladder movement which can contribute to an early failure,

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