pressure relief valve

I been having trouble with my pressure relief valve driping on my efm stoker. The first thing i did was go and get anew one. A 30 PSI WATTS RELIEF valve,the same that i installed 5 years ago when i installed the stoker. It worked fine for a week then started dripping again. My next move was to change my seetings on the aquastat. I first had 170 low 190 high to crank my radiators alittle hotter. Ithen went to the recommened setting of 160 180 with no change in dripping. I checked the temp at the relief valve with a infrared thermal non contact thermometer,it was 142 .At my outlet to on top to the feed it was 147 after just shuting down. any help would be appreciated. This is ahot water system. Thanks Rick

Put a bucket under the vent pipe and pop the valve a few times to see if it reseats. Sometimes they will, sometimes they won't. The temperature has nothing to do with it's operation. What pressure is your system at?

What does your pressure gauge say?
Could be your expansion tank, or your boiler feed.

If your pressure is up around 30 psi and your water is hot. You can try to bleed a little pressure off. Not to much just enough to get it down under 25 or so.
How many stories is your house? The higher the radiators above the boiler the higher the pressure.

It could also be a pinhole leak in the domestic water coil.

I vote for pressure tank issue. But the pinhole in the hot water coil is a possibility. Try to figure out if it leaks a little now & then (expansion tank with not enough room) or the same amount all the time (pin hole). If it's a pinhole, seems it would get much worse real fast.

it seems to leak now an then,maybe a quart over 24 hrs. I have 2 things i.m going to try one is put acompersion fitting ball valve onthe feed to the hot water coil. The other is to drain off some water and see if the expansion tank is filling and venting.When it rains it pours, i,m in the middle of remodeling my kitchen and have to bypass the radiator to put the new floor in and still have heat. A friend on mine suggested 3/4 compression fitting ball valve with pex pipe to bypass the radiator instead of copper. Has anyone ever used the pex on a hot water system befor,and is thereanything I should know? Thanks Rick

Pex is a good choice. I'd use 'shark bite' fittings, then you can mate the 3/4 copper directly to the pex piping. Allow for expansion in the pex, hook it up, bleed it, enjoy. Don't forget to get the removal tool for the 'shark bite' fittings, so that you can take them apart when you need to. THEY CAN BE REUSED MANY TIMES, or remain as permanent. The fittings aren't cheap, but you can hook hem up in seconds and get back to the kitchen remodel. I'd get that ball valve on the tankless coil and look over the expansion tank issue. Is it a newer pressurized (xtrol) one or the older solid tank, less rubber ballast type? Most big box stores have the fittings, and all supply houses, too. Some hardware stores are catching on too. Instant results, no soldering, no leaks,......no brainer!

Pex is only good to 180 degrees I believe . Not sure if the fittings will hold if it gets much hotter than that .

It sounds like the expansion tank is too small, or bad.

Compression fittings are not allowed on boilers. I guess technically the hot water coil is not part of the boiler, but I wouldn't use one unless it was for a test only. No matter what, make darn sure you do not defeat the pressure relief valve.

I know that there are alot of misconceptions about draining the ceiling expansion tank, even among service personnel. A few think that opening the drain valve will drain them, but it doesn't. They can become air bound. To completely empty the tank, you might have to stick a small piece of tubing up through the drain valve and up to the the top of the tank to break the vacuum.

Some ceiling tanks never cause a problem and some are troublesome. If they are filled with water and not drained properly, you'll have the problems you are. (Along with a pinhole leak in the coil or bad PRV)

One way to separate the two is the leaking coil will cause the pressure to stay high, where the expansion tank will cause the system pressure to increase along with the temperature.

Stoker man I leaning toward the exp tank,it seems to leak more at night whren it gets colder and cranks more. could you please explain in alittle more detail how you drain the exp tank. I have filltrol withextrol tank with a diaphragm its pre charged to 12psi. it is mounted overhead. down the bottom is avalve that looks like atire valve with apin that pushes in. If i can,t get this working,is their a better tank to use than this. Thanks Rick

I thought a relief valve only opens when the pressure gets over 30 psi. I wouldn't think one would drip but open once the pressure builds up. That said I really am just thinking out loud and don't know for sure. I can tell you that I had a problem with two relief valves leaking. They were only a month old. They would not reseat-tried everything. I bought another brand and have not had any problems. I just took a peek and it says Watts on the side.

Rick, Now that we know you have an Extrol tank, it could be that the bladder has leaked and water got behind it. It that's the case, it's shot. From here on, it's detective work. If the valve is pointing down, does water come out if you press it? An Extrol tank is a good tank. Mine is over 30 years old.

Stoker man I pressed the valve 2 times just for a split second and only got air. RICK

If you were able to close the water inlet to the boiler and reduce its pressure to zero, what is the pressure in the expansion tank? Then open up the water inlet again. Can you turn off the water to the coil at the same time and relieve the line pressure. Leave the coil water turned off, but the boiler water inlet re-opened. If the pressure stays normal and the expansion tank is charged, then the only thing reasonably left if the water make-up valve (water inlet).