New Water heater and exspansion tank leaking out of PRV. HELP

Over the summer my hot water heater started leaking water out of the Temperature/Pressure Relief Valve (PRV). About 10 days ago, I changed out the water heater and installed a new energy efficient gas water heater (whirlpool model number ND50T122-403). Installed it fairly easily with just some minor retrofitting for the venting as this unit was a few inches higher that the original. Come to find out the actual culprit of the leaking was the expansion tank (2 gallon). The bladder had failed. I bought a new 2 gallon expansion tank from Lowes (Utilitech model LET-2). I also installed new fittings coming out of the wall as the gate valve was old and slightly leaking. I replaced it with a ball valve. I thought I had the problem figured out. I was still leaking water out of the PRV (over 5 gallons a day!) I bought a pressure gauge and checked my home water pressure which was right around 100 psi! I went to the street and adjusted it down to 50 PSI. I matched the PSI on the expansion tank to match. I'll be damned if it is still leaking! water temperature inside the house is 122 degrees. (seems perfectly normal). There must be some simple procedure that I am not following. I am going crazy.

Hot water temp: 122
Street water pressure: 50PSI
Expansion Tank pressure: 50PSI

http://pdf.lowes.com/installationguides/091194008415_install.pdf (expansion tank)
http://pdf.lowes.com/installationguides/035505146700_install.pdf (water
heater)

Thought I had it fixed again. Went 16 hours yesterday without a drop of water coming out of the PRV. The water heater came on a few times yesterday to heat water and nothing came out! Went to sleep and woke up to a full bucket (5 gallons) of water or more (overflowing) out of the PRV. That seems like a large amount of water being relieved out of the PRV. what am I missing???

Thanks for your help.

Water heaters on the fritz are not necessarily something a DIY'er should mess with. Too much risk of injury and/or death. You need to have a licensed professional check it out. I suspect the T&P should be replaced.

BTW: water heaters do not have PRV's. That abbreviation is for pressure reducing valve. The valve you are referring to is a temperature and pressure relief valve. T&P is how it is usually referred to.

Yes I am referring to the T/P Valve coming out of the water heater. T/P Valve is brand new and came on the the brand new water heater....

rovobay said:

Yes I am referring to the T/P Valve coming out of the water heater. T/P Valve is brand new and came on the the brand new water heater....

Click to expand...

Any mechanical device can be faulty right out of the box but is more likely something is spiking the pressure or temp. You need to have it checked for you and your family's safety.

well it is not the t/p valve. I caught the water heater in action, dripping. I checked the water pressure on the hot water spigot and it read 150psi and the expansion tank also read about 150PSI. I relieved the pressure and the water pressure went down to 50psi as well as the expansion tank. it took about 2 gallons to relieve the pressure back down to 50psi (on a 50 gallon tank) that seems like a lot of expansion!!!

I read somewhere that there is only about a cup of water worth of expansion for every 10 gallons. 50 gallons would be 5 cups worth of expansion volume.

what could my problem be? missing dip line? heat trap nipples? the water heater came with 2 heat trap gaskets like these. http://waterheatertimer.org/images/IMG_2162-heat-trap-washer-1.jpg which i removed prior to installation, but I don't think this could cause all this pressure buildup.

I wonder if a 5 gallon expansion tank would be a better bet.

You really need to give it up before somebody dies. Call a local professional while you still can.

Watch this to see what a bomb you are dealing with.

[ame]http://www.youtube.com/watch?v=5pVQryuKMj8&sns=em[/ame]

it was the pressure reducing valve. case solved after a few controlled tests were preformed.