Pressure gauge shows "20", when water has been drained from tank

[JustRay]

Hey folks

I'd appreciate some advise.


My well tank:
WELL-X-TROL well tank
Brand: Amtol
Model: WX-203
Serial: P2334994
Tank Volume: 32 Gallons
my pressure switch has a sticker inside of it that reads 30/50

Everything seems to work fine.
It's just that I have never EVER, checked the air pressure in the well tank and thought, after watching some you tube videos, that it sounded like a smart and easy thing to do.

My goal is to drain the water, then ensure that I have 28 lbs of air pressure inside the tank before re-filling it.

However, when I empty the tank, my gauge still shows 20 Lbs.

I have watched some you tube videos where this happens (their videos show their gauge at 20 when the tank is empty) but they never mention it as if it is an issue.

Most You Tube videos, show the gauges with a value of "0" when the tank has been emptied of water.

So, what the heck might be going on with my gauge\well tank, do you think ?
This procedure "seemed" like an easy one to perform (especially for a newbe like me.).
But, now I'm very confused.

Advice would be GREATLY appreciated.

Just Ray in rural Wisconsin

 

[Bannerman]

However, when I empty the tank, my gauge still shows 20 Lbs.

Assuming the gauge you are referring to is the pressure gauge on the plumbing system after the pressure tank (not the tire pressure gauge to check the tank's air pre-charge), if the system has been drained so there is no further water flow from an open faucet, then it would appear the gauge may be defective and will need to be replaced.

 

[Sponsor]

 

[JustRay]

Thanks for the quick reply.
It is the pressure gauge on the plumbing system.
Replacing the pressure gauge looks like a pretty easy thing to do.
So methinks I'll pick one up the next time I'm in town.

Thanks again

 

[Jadnashua]

Once you've set the precharge properly on your tank then turned the pump back on, the air pressure you read on the tank will be the same as the water pressure so you can use that as a cross-check on your water pressure gauge- the water pressure will just push back on the bladder keeping the pressure equalized on both sides with the bladder moving back and forth as the pressure in the water system changes.

You don't want the tank's pressure to be precharged higher than your normal, otherwise, it will keep the pressure up until there's no water left. YOu want a little water left in there when the pressure switch activates to give the pump a chance to start refilling things before the tank is empty.

 

[Valveman]

When a gauge doesn't go to zero when all the water is emptied from the tank or you have the gauge off and in your hand, you need a new gauge.

 

[Dremerr22]

Assuming the gauge you are referring to is the pressure gauge on the plumbing system after the pressure tank (not the tire pressure gauge to check the tank's air pre-charge), if the system has been drained so there is no further water flow from an open faucet, then it would appear the gauge may be defective and will need to be replaced.

What if tire pressure gauge reads 20? I had a pipe burst between my well pump and pressure tank which then caused my pressure tank to lose water.

Thanks in advance! -Dre

 

[Bannerman]

What if tire pressure gauge reads 20?

I don't understand your question.

A tire pressure gauge is normally only utilized to test the tank's air pre-charge pressure.

A captive pressure tank contains two chambers, a water chamber which temporarily stores a small volume of water provided by the well pump, and a sealed air chamber which is to contain a volume of compressed air which is utilized to maintain pressure within the plumbing system while the pump is shut off, and to push water out from the tank whenever a faucet is opened initially. The two chambers are separated by a flexible diaphragm which allows the compressed air to exert force on the water without any loss of air when the tank contains 0 water.

The tank's air precharge pressure will usually be set at 2-5 psi lower than the pressure switch Cut-In setting. For example, if the pressure switch pressure range is 40/60, the pressure tank's pre-charge pressure will usually be set to 38 psi, so when the pump is activated @ 40 psi, the pressure tank will then contain only a very small quantity of water.
The air pre-charge pressure is always tested and adjusted while the pump is not powered and after the plumbing system is drained completely of water.

I had a pipe burst between my well pump and pressure tank which then caused my pressure tank to lose water.

In that circumstance, it will be totally normal for the pressure tank to contain 0 water.

Unless your pressure switch setting is 22/42 psi, 20 psi tank pre-charge would be unusually low.

To better understand how a pressure tank functions, see the interactive demo at the link below.

Interactive demo

 

[Reach4]

If the pump is off, and you have drained the water, then your pressure gauge is bad.

If your pump is running, and it is a jet pump, and you can only get to 20 psi, the jet may be clogged.

 

[Fitter30]

Gauges today are junk. Tear it apart plastic parts not all brass. Sad but true. Even bevel glass oil filled.