Pressure relief valve won't stop dumping water


Old 12-13-13, 12:47 PM
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Pressure relief valve won't stop dumping water

So a few days ago I checked on the boiler and it was pinned at 0psi but the system was still heating fine. But I feared burning out the pump so I went ahead and filled the system with a little more water until it hit 12psi. I didn't add a TON of water or anything. The boiler was not running at the time.

After running it spewed up a good amount of water (figured I overfilled a little). However it's kept spewing out water over the past couple of days! Right now the system is off and at 19psi but the 30psi relief valve is still dripping water at a constant rate. The valve is rather new (got it a little over a year ago). I'm guessing the valve is bad already since it's leaking at 19psi which it shouldn't. I also just had a new expansion tank put in but have no idea how that works really lol.
Just frustrating because obviously the 0 psi it was at was not good, so I filled it and now I have problems. Should I have left it? ugh lol
Any advice would be great thanks.
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Old 12-13-13, 12:54 PM
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It could be that your gauge is off. See the thread at the top of this forum on how to verify your boilers pressure gauge.

Last edited by NJT; 12-13-13 at 03:39 PM. Reason: you guys need to learn how to copy and paste links!
Old 12-13-13, 03:23 PM
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Yes I just made another gauge (lost the other one) yesterday to check my pressures. Cost about $10 to make. Just need a hose bib to 3/4 pipe thread adapter, a plug with a hole on top for gauge and a gauge. Screw them all together and screw into hose bib and check. Granted my $4 gauge was a few PSI off from my boiler gauge, but it lets you know you are in the ballpark. Verify the gauge and check bad. Yes the valve can be bad or have some crap under the seat, but there has to be a reason for the pressure loss and initial blow off.
Old 12-13-13, 03:33 PM
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I would trust the relief valve before the gauge.
It's possible the gauge went bad and instead of going from 0-12 you went from 19-30.
Maybe there never really was a pressure drop, just a bad gauge.
Old 12-13-13, 03:45 PM
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All the guys are right... the pressure gauges that are supplied with boilers are the cheapest pieces of dookie they can get. They are almost ALWAYS bad.

In the interest of SAFETY, as Spott has said, NEVER ASSUME that the relief valve is the culprit. ALWAYS err on the side of caution!

If there's ever any question whether the relief or the gauge is bad, TRUST HISTORY... ALWAYS suspect the gauge is bad. History was invented for a reason! So that we don't continue to make the same mistakes... over and over and over ...

Read this one also:

The step-by-step instructions in that thread explain how to properly check and charge the air on an expansion tank, and this should be done at LEAST every two years, preferably ANNUALLY.
Old 12-13-13, 04:23 PM
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system should be 12psi cold auto feed then when I runs right after it satisfies the stat tops 20psi the relief is doing it's job pressure reading is can't over fill a hot water baseboard system just over pressurize it..drain the expansion tank on next cycle off water has no place to expand if it is full

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