Troubleshooting low pressure tank cycling PSI

[Torch Lake Tom]

Friends: I have an 8 year old 44 gal. Well-X-Trol working with a 40 to 60 PSI Square D on a 7-year old 1/2 HP submersible. The pump has an in-well Cycle Stop Valve (also aged 7 years) connected to it. The other day, I just happened to notice that the pressure tank gauge was only around 20 PSI! I had not sensed any pressure problems from our house fixtures. I determined that the cut-on pressure was only 17 PSI and the cut-off was about 37 PSI. I attempted to adjust the cut-on switch (starting with about 3 turns of the adjustment nut) and this made no difference whatsoever in the aforementioned cycle pressures. Tank was drained completely and the diaphragm pressure measured about 25 PSI. I was able to pump this up to about 36 PSI with a bike pump but for purposes of troubleshooting, stopped there as it was taking forever to put more pressure in the bladder. [I should note that with the pump off, house valve shut and pressure tank spigot open, the water continued to flow slowly out of the spigot for quite some time which, coupled with the significant effort to get the pressure up in the bladder, caused me to suspect a possible pin hole leak in the diaphragm, although I was not sure if this would explain the inability of the cut-on pressure to move higher than 17 PSI]. As I had a new replacement pressure switch available, I replaced that at the same time and recharged the system. Again the identical PSI cycle as noted above. There was no short cycling as the tank took at least a minute to fill. It took at least four minutes to drop from cut-off to cut-on with a high volume laundry tub faucet open. The tank was again drained and bladder pressure checked and it was still holding steady at around 36 PSI. Fired up the system again with the identical cycle pressures noted. I did not suspect nor swap out the pressure gauge as it was both consistent in the cycle and depicted the appropriate 20 PSI differential, but I could certainly be wrong about this being a problem. I cannot figure out what is holding my cut-in PSI threshold down and am now suspecting something associated with the well pump or the Cycle Stop Valve. Any suggestions for troubleshooting this would be much appreciated! Thanks very much in advance!!

 

[Valveman]

I would replace the pressure gauge before making any other observations. I trust a 40/60 switch to stay 40/60 more than a pressure gauge to tell me the truth. You can also use your tire gauge to verify the water pressure gauge, as they should read the same when the pump is running and there is any water in the tank. If "You just happen to notice the tank gauge", it is probably lying to you. You would have noticed only having 17 PSI without having to look at the gauge. If the pump stays running for as long as a faucet or shower is on, the CSV is good. If the pump builds up in a minute or two and shut off after turning off the faucet, then the pressure switch is good. If the water runs for 4 minutes at high flow before the pump comes on, then tank is good. Most likely everything is good except the 5 dollar gauge.

 

[Sponsor]

 

[Torch Lake Tom]

A belated thanks Valveman for your great advice. The problem was indeed with the gauge. Very much appreciate your thoughtful and thorough response.

 

[LLigetfa]

The Bourdon tube inside the pressure gauge is easily damaged by even a light frost. Some folks will mount it on top of a riser pipe with a ball valve at the bottom of the riser that is only opened when needed. That way there is air trapped that with the ball valve closed takes longer to be absorbed into the water.

Another approach is to get a pressure gauge with a garden hose thread and mount it on the drain cock only when you need to see the pressure. Remove and store it in a warm place when not in use.