Is this relief valve needed or required?

[Gagecalman]

This was installed at my friend’s house years ago when the plumber added the plumbing for the washing machines. It just started to drip.
If I open the faucet on the sink it stops dripping but starts as soon as I shut it off so I don't think the pressure is increasing that fast.
He was told it's required. I didn't know so I thought I'd ask the pros.
The house is on public water and has an expansion tank on the water heater.
If it's not required can I install a threaded plug into the bottom?
Thanks for the help!

 

[Reach4]

I would think so. It would be more compact to unscrew the relief valve, and put a plug into the thread that the relief valve is currently screwed into.

If you can unscrew that knurled cap, you may be able turn a screw to raise the relief pressure.

 

[Sponsor]

 

[Sylvan]

I would think so. It would be more compact to unscrew the relief valve, and put a plug into the thread that the relief valve is currently screwed into.

If you can unscrew that knurled cap, you may be able turn a screw to raise the relief pressure.

Not a great idea as model plumbing codes frown upon a "dead end" on the potable water system as it can cause contamination due to stagnant water

Remove the copper tubing as close to it connects BUT I would take a pressure reading prior to removing any safety devices

 

[Gagecalman]

So no reason to have it?

 

[John Gayewski]

So no reason to have it?

What is this attached to? If it's dropping it needs replaced not deleted. You need to trace it and see where the piping connects.

 

[Reach4]

What is the PSI of your water while this is dribbling?

Is the dripping continuous or intermittent?

 

[Jeff H Young]

it might be a relief valve set at a lower pressure setting than T and p on water heater (assuming its not plugged) water heater might be in spot that wouldnt be agreeable to discharge from t and p. so they add another one at a lower setting and protect from water damage just a guess. generaly what I see in picture is un needed but gotta be a reason its there

 

[Gagecalman]

It is just tee'd off of the cold water pipe that runs down to the washers and ends at the utility sink.
There is a T&P valve with a drip tube on WH.
He told me the plumber said it was required. It's been there about 14 years and just started dripping.

 

[Jeff H Young]

gagecalman,
If water drips from T&P where ever it terminates and that's fine with you. than go ahead and plug it off, or re rout the T&P to a suitable location.
I don't think you need a relief valve there .but it might be a good idea. hope you understand why it might be desirable

 

[John Gayewski]

I think someone was using this as a hammer arrestor?

 

[Reach4]

I think this could have been put in before the thermal expansion tank.

I still think OP should check the water PSI while dipping.

That pressure relief valve could be a common 75 psi used with home wells, and that would be expected to dribble, even if there is a functioning thermal expansion tank. On most of those valves, you can unscrew the knurled cap, and adjust the pressure within limits.