Well pressure tank not filling much

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Thunder Bay
I installed a new well pressure tank with brand new fittings, control box, and pressure gauge as my old one had failed.

On my old tank it had condensation on the outside from the warm air in the basement. The new one in the last 6 months has not had a drop of condensation on it but all the T fitting pieces do.

When I press my ear to the tank it sounds like a small trickle of water is going in but 90% of the tank sounds hollow. When the psi reaches 38 it kicks the pump on for 10 seconds until it hits 51 again and water can be heard trickling into the tank even after the switch has shut off.

The switch is set for 40/60 and at 38 it kicks on like it should and within 10 seconds it cuts out at 51 and.never hits 60. It seems like after an hour it loses about 5 psi without water running. I do have a 6 stage reverse osmosis hooked up which has a drain hose going to a drain pipe for waste water.

This does not seem normal as I would expect the pump to run longer to fill the tank, and I would also expect the tank to be heavy to lift but it seems mostly empty. It is a 20 galon tank.

Also, a side note. once in a while I hear my reverse osmosis water filtration system whine for a few seconds like it is relieving pressure.

Any ideas what the problem could be, or is this normal? I don't understand why the switxh only brings the psi up by 13 before shutting off.


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Cary Austin
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Lubbock, Texas
A 20 gallon tank only holds 5 gallons of water. It should not feel heavy. But a 10 GPM pump should run for 30 seconds before filling the tank. The tank should also deliver 5 gallons from a faucet before the pump comes on. Sounds like you have too much air in the tank. You need less air in the tank than the pump start setting. About 35 PSI air in the tank and it should hold 5 gallons before the pump shuts off at 60. But even with the tank holding 5 gallons as it should, the tank is not half large enough for that size pump. You either need a much larger pressure tank or add a Cycle Stop Valve to what you have.
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