What replacement pressure relief valve does this take?

Can I replace it by shutting power, draining tank, replacing valve and turning power back on?

They are all pretty generic, usually 3/4 IP THREAD. Turn off the gas or electric and the water to the heater, open a faucet located above the heater, connect a garden hose to the bottom tank valve open the valve and drain the heater water level below the TPV. Remove the old TPV and replace. HOWEVER, have you tested you house pressure regulator to make sure it is not the issue?

I think he is referring to a pressure tank on a well system. If that's the case, then you have described how to do it. This is a pic of one.

pressure relief valve water well - Bing Images (http://www.bing.com/images/search?q=pressure+relief+valve+water+well&view=detail&id=15408BADDDD95994C27F865DBC8080C031EC3A40&first=1)

This is a terrific article on them. Still, it's not rocket science. Remove old valve, install new one.

Water Tank Pressure Relief Valve - how to find, buy, & install safety valves on water tanks and on well water systems (http://inspectapedia.com/water/WPControlsa.htm)

Just curious. What makes you think you need a new one?

Thank You, old pressure valve is leaking. .

You may think you have a.O. Smith but what you have is a Gould. Bladder tanks don't have "pressure relief valves" are you referring to the snifter valve on top of the tank? If so you can simply shut the pump down, open up a cold water tap to relieve the pressure and replace the stem in the valve. This tank comes from the factory precharged at 38 PSI. If your cut in point is above 40 PSI charge the tank at 2 PSI UNDER the cut in point on the control box. Good luck, Tom

Definitely an AO Smith V60 with a pressure relief valve as shown in a previous response.
Thanks

Definitely an AO Smith V60 with a pressure relief valve as shown in a previous response.
Thanks
Here's the specs on a V-60 bladder tank
A.O. Smith 20 Gallon Pressure Tank
Get a better tank for less money with the same space requirements, easy retrofitting for Amtrol tanks with the toughest coating in the industry!


Protective Air Valve Cap with Seal: Seals after installation; Tamper-proof
Ultra-UV Powder Exterior: Excellent for outdoor use! Rated to automotive standards; High gloss exterior finish
Pure Butyl Rubber Diaphragm: Strong and flexible for smooth operation and long life
Positive-Lock Diaphragm Seal: Seals diaphragm directly to shell; Insures permanent separation of air and water
Virgin Polypropylene Liner: Proven protection against corrosion; No water to metal contact
100% 304 Stainless Steel Water Connection: Stainless stell acceptance collar and stainless steel elbow; Assures no dissimilar metals ionization
Corrosion Resistant Base: High-impact corrosion resistant material; Strong and stable for long life; Base rotates for easy alignment to pipe connections; Slotted and notched for air flow; reduces condensation build up at the base of the tankhttp://store.kgpowersystems.com/v60-goulds-pressure-tank-water-stand-type-19-9-gallons.aspx

Show me a "pressure relief valve"
Can't do it? That's because bladder tanks don't have any. Why would you wish to "relieve pressure" in a tank that's designed to hold pressure,
Brain had the right idea in post #2, A pressure relief valve ( called a T&P valve) will be found on water heaters. And Goulds does .indeed manufactures the V- 60 tank Here's a link to check out. Tanks look the same? That's because they are.Rgards, http://store.kgpowersystems.com/v60-goulds-pressure-tank-water-stand-type-19-9-gallons.aspx
Reading up on water tank pressure valves they are a add on. They don't come with the tank. They are installed to prevent the bladder tank from exploding, ( when's the last time you heard of that happening?" due to the pump failing to shut off. If the tank manufactures had thought a pressure relief valve were necessary they would have built them in. Water heater factories did. I think they're a scam just like Rid-X and Septic Savior. Regards. Tom

Mark, the only thing I can add is this. If you look at the picture I linked above and see that your system has a PRV similar to the one in the pic, and that is what is leaking, then simply replace it. However, if it is the air valve towards the top of the pressure tank itself that is leaking water, then your tank's bladder is ruptured and the tank should be replaced. However, I think it is a PRV you are referring to.

One more item. Just be sure it is not leaking water because the system pressure has not crept up towards 75#. Many PRV's are preset for that pressure and that could be why you see it leaking. You have probably already ruled that out. Just thought I'd mention it.

It was the PRV, I repl;aced it along eith pressure switch and all is fine. Easy, thanks for your help.

Definitely an AO Smith V60 with a pressure relief valve as shown in a previous response.That was a earlier post

Today, 06:59 AM
T was the PRV, I repl;aced it along eith pressure switch and all is fine
Gee! Somehow I feel snookered. All this back and forth about a Pressure relief valve only to find out the OP wasn't familiar with plumbing terms.
Any how I did learn the a pressure relief valve for bladder did exist even 6though they were unnecessary and a extra expense you don't need.
And Mark, Glad you got your problem solved. Good luck, Tom