The pressure gauge connected to my well water tank is dripping very slowly. Maybe few drops per day. I am guessing this based on the accumulated water in the container underneath. It seems that liquid is overflowing from top of the pressure gauge. At the top, there is a hole, function of which is not clear to me. Could someone tell me why there is hole at the top? And why water is coming from the top. It could be total coincidence but I observed this first time when outside temperature became very cold below -5˚F last week, and it’s dripping since. Is this something I can change myself or should I call a plumber? And how soon I should fix it. Thank you.
Plumbing – How to fix water leak coming from pressure gauge/valve on water tank
leakplumbingwater tank
Related Solutions
At 140 psi, either that valve is shot, or you need to install/check your expansion tank. To know for sure, after running some water for a second, stop any running water and check your pressure again. If the high pressure only occurs after the hot water tank has been heating back up, then what you really need an expansion tank.
To replace this valve, after turning off the water, unscrew the union fitting on the bottom of the PRV (at least I'm hoping that's a union, it should be two pieces and the nut should move independently from the pipe). You should be able to work on that with a crescent wrench one partial turn at a time. Then with that disconnected, you should have some play in the pipes to pull it slightly out from the wall and unscrew the valve from the top threaded connection. Installing the new valve will be a similar procedure in reverse, just clean off the threads and apply some pipe dope to the male threads first.
What you pointed at is the pressure relief valve. Seeing that the pressure is fairly low, it could either need adjustment or be failing.
The pressure relief valve is basically there to release very high pressure before a pipe/filter/faucet relieves it (eg: blows up). It's basically just a spring pushing against a piston.
You can try adjusting it first by turning the end clockwise just until the flow stops. Best to do this at the pump cut-off pressure (which is the highest pressure you'd normally see) -- basically open a tap until the pump runs, wait for the pump to shut off, and then adjust the relief valve. A lot of the valves actually have a ridged edge you can turn, though yours looks like it probably requires a nut/screw driver or pliers.
If that doesn't work, it is probably just that the valve is failing. Could be a cheap valve or have a manufacturing defect, or could be corrosion. Replacements cost a few dollars at any home improvement or plumbing store and are very easy to install (use teflon tape on the threads).
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Best Answer
The hole is to provide atmospheric pressure inside as a reference for the gauge. That is, the pressure indicated is relative to ambient pressure. Or, in other words, the gauge indicates how much more pressure there is inside the pipe than outside the gauge.
If the gauge is leaking through the air vent, it is time to replace the gauge. The internal mechanism has failed, probably by rusting through or otherwise breached the pressure-sensing diaphragm.
Freezing conditions could well stress the gauge possibly due to a little ice build up.
Yes, this is something most anyone can do. Turn off the pump and relieve the pressure in the line (open a faucet). Using a wrench, vicegrip, or similar tool, unscrew the gauge assembly (gauge plus its short input pipe). Using the tool, grasp the gauge's pipe which comes out below it. There should be a four- or six-sided grip (turn it counter-clockwise as seen from above.
If it has been installed for a long time (years), it will be reluctant to turn at first. A longer handled tool will provide more torque, but take care to provide counter-torque to the pipe it is screwed into to prevent damaging other parts of the plumbing. (Provide counter-torque with another wrench or tool attached to the plumbing near where the gauge is screwed into. If the wrenches are about 90° relative to each other, it is convenient and efficient to twist them opposite to each other so that the water pipe experiences greatly lessened torque.)
Once you have the old gauge assembly out, take it to the parts store for a suitable replacement. Consider using a fine wire brush to clean the seat (the threaded hole the gauge is screwed into); Teflon tape makes it easier to insert the new gauge.
I wouldn't wait long; do it in the next few days. It will leak more and more the longer you wait.