T&P valve still drips after replacement on boiler

Empire_2

20 psi,....Huhhhh. are you sure that is accurate? I cant tell you how many times I have found either a little off and way off the actual pressure. If you need service call some one or you can drain boiler and see if the gauge zeros out. Could also be a leaking through PRV.

Mike T.

Jonni

T&P valve still dripping after replacement on boiler

All

I have a Peerless wbv4 and noticed my T&P was dripping constantly.

I replaced T&P and water is still dripping.

Any ideas other than it being a 'bad' new T&P??

Boiler is @ 20lbs PSI

Thanks

John McArthur_2

Have you checked the expansion tank? If the bladder loses air side pressure the relief will discharge every time the boiler heats up. Sorry if you already know this.

scrook_2

T&P?

Should be just a pressure relief on a boiler, vs. Temp & Press on a water heater -- in any case I'd suspect the gauge reads low but could be a lot of crud in the boiler water and you got a piece embedded into the new relief valve? What happens if you drop the pressure to 15 psi? How high's the top radiation from the boiler?

Jonni

Good thought Mac

I will change out the expansion tank. One question I have is when I drain the boiler down to 0 and change out the tank do I have to worry about the cold water supply 'shocking' the sections and potentially cracking one.

Basically what is the rule of thumb when draining the boiler down and pressurizing it back up?

Thanks

Tinman1

Read "pressure relief valve blows off" from a previous post.

Jerry_15

Pressure on the tank needs to be the same as the operating pressure of the system. Common screw up: Ex tank replaced with domestic ex tank pre-charged to 60 psi. How do you know? Dom tank has 3/4 thread, hydronic tank has 1/2". How do you fix it? Let air out of the tank and check it with a tire gauge until it's at 15 psi.
If it's the right tank and there's no pressure or water comes out, replace it. Turn the water feed off first.