Pressure jolt

[Pops52]

Recently, I have noticed a change when my well pump starts. 62 gal pressure tank set at 50/70. When the pressure draws down to 50 and the switch closes, for a split second there is a drop in pressure to 40, a small "jolt" then back up to 70. Never noticed this before last week, and now during a shower, I can notice the surge when the well pump kicks on. Bladder checks out ok. Any thoughts?
Dave

 

[Reach4]

Check the air precharge. Air precharge is always checked with the water pressure zero. Your description seems compatible with the precharge being too high. Air precharge does not often rise over time, but could if there is a small leak letting water slowly seep into where water should not be. If that is happening, replace the tank.

Submersible (down the well) pump? If so, the air precharge should be 48 psi. If an above-ground pump, you would need lower than that typically.

One other possibility is that your pump has a control box, and the start capacitor is weak. However the delay for those to start is usually more variable than what you describe.

 

[Sponsor]

 

[Pops52]

Check the air precharge. Air precharge is always checked with the water pressure zero. Your description seems compatible with the precharge being too high. Air precharge does not often rise over time, but could if there is a small leak letting water slowly seep into where water should not be. If that is happening, replace the tank.

Submersible (down the well) pump? If so, the air precharge should be 48 psi. If an above-ground pump, you would need lower than that typically.

One other possibility is that your pump has a control box, and the start capacitor is weak. However the delay for those to start is usually more variable than what you describe.

Thanks @Reach4 , I checked precharge and it was 50+-, I dropped it to 40. Down hole pump. Control box less than 1 yr old. Pressure tank is 25 yrs old so ruptured bladder was my 1st guess. No water came out of schrader valve. I might just get a new tank and have it ready.......

 

[Reach4]

If the pressure switch kicks on at 50, usually 48 is good. Ideally, the tank is good, but you had never noticed the dead spot that was happening. Or the temperature at the tank rose, and that increased the precharge by expanding the air.

Setting the air precharge too low is harder on the diaphragm.


After setting the precharge to 47 or 48, check it again maybe a week or two later . If it rises again without a temperature rise occurring, know that tank will need replacing soon.

Since the Schrader valve is on the top, don't expect water to come out of the Schrader valve.

There is currently a shortage of pressure tanks.

 

[Valveman]

Pressure increasing in the air charge of the tank by itself is a sign the diaphragm is broken. Probably been broken for a long time. Bladders and diaphragms in tanks are broken from the pump cycling on and off too much just like everything else in the pump system.

 

[Pops52]

Thanks guys. It has been HOT here in N Calif. and the garage has been 90-100’. I’ll recheck air pressure in the early am with cool water in tank.