Do I need a new pressure gauge?

[GeorgeE630]

Yesterday I tried to increase my water pressure and noticed that the pressure read from the top of the pressure tank with a tire pressure gauge did not match the pressure shown on the pressure gauge used by the pressure switch.

	Before Draining Tank	After Draining Tank
Pressure read from top of tank	49 PSI​	32 PSI​
Pressure read from pressure gauge	59 PSI​	56 PSI​

I'm not sure whether those 2 pressures are supposed to match or not, but something doesn't seem right.

After a couple hours the pressure gauge finally normalized down to ~34 PSI, and the tank pressure still shows 32 PSI, so maybe the pressure gauge is just slow/dirty?

Also, yesterday I drained the tank, checked the pressure and it was showing something like 20 PSI, so I pressurized it until the tank was at 38 PSI since I'm planning on going with a 40/60 setup. I don't remember exactly what the pressure gauge showed before I added air to the tank, but I remember it showing more than 20 PSI.

So ya, not really sure what's going on, but any help would be appreciated!

 

[Bannerman]

When the pressure tank is continuing to reliably hold the intended pre-charge air pressure, and when further pressurized with water from the pump, the tank's air pressure reading and the system dial guage reading should be essentually equal.

When the pump is de-energized and the pressure tank is drained completely of water, the tank's air pressure reading should equal the precharge pressure (ie: 38 psi) while the system dial guage should read 0 psi.

If the sysyem pressure guage/pressure switch response is slow, remove the guage & pressure switch to either replace or rod out any potential blockage that is within the nipple and threaded port that is supplying pressure to the guage & pressure switch.

 

[Sponsor]

 

[WorthFlorida]

Pressure gauges do not react slowly unless there is severe corrosion. Is there a check valve after the pressure tank? This would explain when the tank is drain, house pressure remains.

Do you have an irrigation system that is tied to the pressure tank? If yes someone added the check valve. When the irrigation is running it can drop the pressure enough that when a faucet is opened, air can be sucked in If the irrigation is tied in between the tank and a check valve

 

[Valveman]

Yeah I think your water pressure gauge is stuck. It should read zero after draining the tank. But it is common for the air pressure gauge and water pressure gauge to read a couple pounds differently.