Water heater continuously running and water pouring out relief valve drain line

[Chris Milot]

Hello everyone,

Hoping to get some help on this. I installed a new water heater about 3 months ago and everything has been working fine. Today when I went in the garage I heard the water heater running or refilling which I didn't think anything of. Went to the store and came back and it was still running so I looked in our side yard and water was running out of the pressure relief valve drain line. I turned the water off to the water heater.

I know it's a safety device to prevent the hot water tank to build up too much pressure but this thing is brand new (Bradford/White) from a plumbing supply store. Any ideas what I can do to fix this? Is this a faulty pressure relief valve? Something else going on?

Thanks for any help on this!

 

[Phog]

It could be a couple different things. First if your incoming pressure went up (regulator on the city water service line) then the T&P will see that increased pressure and open up. Second if the T&P opened for some other more common reason (like if you have a bad thermal expansion tank) sometimes the valve gets stuck and doesn't close back up all the way.

 

[Sponsor]

 

[Terry]

I would pick up a pressure gauge from the irrigation isle at a hardware store can check it at a hose bib to see what your pressure is.

If it's over 80 PSI, then a PRV ( pressure reducing valve ) needs work or installation.

The T&P on the water heater is good for up to 150 PSI, so for that to be releasing water, you either have a bad one, or your pressure is way too high.
If you have an electric water heater and the thermostat has failed, and the temperature is running too high that can increase pressure too.

Check the pressure first though. Even a good relief valve isn't going to hold tight if the pressure is too high. You do need them to relieve pressure for safety reasons. Like the water heater blowing a hole through your roof.

 

[Chris Milot]

Thank you all for the help! I hooked up the pressure gauge to the drain spigot and it is reading around 92 psi. This is with the water on and I can see water draining at the side of the house through the T&P drain line. Is 92 too high or is the T&P only supposed to open above 150? Does this indicate a bad T&P? On a 3 month old WH?

 

[Fitter30]

Thank you all for the help! I hooked up the pressure gauge to the drain spigot and it is reading around 92 psi. This is with the water on and I can see water draining at the side of the house through the T&P drain line. Is 92 too high or is the T&P only supposed to open above 150? Does this indicate a bad T&P? On a 3 month old WH?

T&P either opens at 150# or 210*f. Need a pressure reducing valve whole house and a expansion tank for the water heater.

 

[Terry]

You can't check pressure if there is a constant leak. Turn the water heater off, and check at a hose bib after you have stopped the leak.
And 92 PSI with the water running it high. Let's find out what you really have.

 

[Reach4]

Thank you all for the help! I hooked up the pressure gauge to the drain spigot and it is reading around 92 psi. This is with the water on and I can see water draining at the side of the house through the T&P drain line. Is 92 too high or is the T&P only supposed to open above 150? Does this indicate a bad T&P? On a 3 month old WH?

Read the water pressure inside. The outside faucet may be connected before the PRV. Measure at a laundry tap, or the drain valve on the WH.

Still, bad T+P, even if inside water reads 92. Ask for warranty replacement. Does the installer warranty this? I don't know.

On the other hand, buying a T&P valve yourself may be under $20 today, and asking for them to send you one takes time.

 

[Chris Milot]

Ok I turned off the shut off valve to the hot water heater so it's no longer leaking out the T&P drain. I checked pressure at a hose spigot that ties into the cold water line for our kitchen (Right outside our kitchen). Pressure was about 92 there as well. The washer spigot would be very hard to get to right now especially with my currently broken fibula.

When turning off the water to the WH the WH drain valve reads zero. When turning the water on to the WH that's when it read 92 albeit with water coming out the T&P drain line (not a full on blast like a hose spigot would put out but a steady stream that could probably fill up a 5 gallon bucket in 10 - 15 minutes.

I installed this water heater myself. With these checks are you guys confident it is the T&P valve? I'd like to get hot water back up today for the wife and baby.

 

[Terry]

A good T&P will work at 92 easily.

 

[Reach4]

With these checks are you guys confident it is the T&P valve? I'd like to get hot water back up today for the wife and baby.

Yes. Sure.

Test your T+P valve now and then. It must open when you lift the lever, and it must close when you release the lever.

Secondary is that your PRV should be adjusted down, and if it does not work, maybe rebuild or replace. Yet most things, including toilet fill valves, don't misoperate until the pressure is higher. Also, water hammer is more likely when the pressure is even higher.

 

[Chris Milot]

Thank you all! Will head to Lowes or HD to pick one up. It's located on the top of the WH tank. Do I need to drain any water first or should I be good? Any brand you recommend that will hopefully last more than 3 months?!

Thanks again!

 

[Terry]

I would remove the one you have and take to the supply house to match it up for dimensions.
Located at the top of the water heater with the water off you could open the drain at the bottom and drain off just a little into a bucket or hose.
Brand doesn't matter on the T&P.

 

[Reach4]

I bought Watts, I think, but others will work too.

Shut the valve to the WH. open some hot faucets. Some will drain anyway due to your leaky T+P. Then drain maybe a bucket from the drain valve. Do use good ptfe tape.

Loosen the old valve first. If you cannot, you will be buying a wrench, or other tool, while you are out shopping.

Mine had been in place for a long time. I had to restore the galvanized pipe for extra torque, in addition to my big wrench.

I bought a taller one for easier wrench access. The new plastic drain I bought leaked badly, so I had to abandon that, and use the old galvanized pipe. This drains to the basement floor, which is what you do in freezing places.

 

[Phog]

I know this probably goes without saying, but needs to be said anyway: turn the water heater electric power/gas valve OFF before you work on it, and make sure the tank is completely filled up with ALL the air purged out before you turn it back on. Good luck.

 

[Chris Milot]

Thank you all for the help! I truly appreciate all the advice I have gotten on this forum! Replaced the relief valve and it is now working like it should.