Plumbing question Replacing main shut off valve leading from well pressure tank

[Clarence Martinn]

Don't know how or when it happened, but half of the red plastic turn knob on the main shut off valve that is a few feet from the pressure tank that hooks up to the convertable deep well jet pump; it ended up breaking off. Want to replace that plactic shut off valve with a good brass shut off valve. Can I just turn off the power to the jet well pump, drain the water out of the lines untill no more water runs through the faucet; and then replace that valve ? How do I do that and not loose prime in the well ?

[Tom M King]

What kind of pump? If it's a submersible pump it doesn't need priming. If a jet pump, it still should have a foot valve at the bottom of the well that doesn't let the water run back down. If no foot valve, for whatever reason I can't think of, it's not that big of a deal to prime a pump. There is a plug you take out, and pour water in.

Use an USA made metal ball valve, if you can find one, while you're changing it. Ball valves are so good these days that I can't think of any reason to use a gate valve.

[Paul F Franklin]

The jet pump shouldn't lose its prime, but fill up a 5 gallon bucket or two before you drain the system just in case there's a leak somewhere and you have to re-prime. Also, while you have the system drained, check the air pressure in the pressure tank (assuming it's a bladder tank). It should be pressurized to 2-3 psi below the pump's cut in pressure. So if the pump turns on when pressure in the system drops to 30 psi, there should be 27-28 psi in the pressure tank when all the water is drained out and the drain valve is open. You'll find a schrader valve (like on a tire) under a small cover near the top of the tank; that's where you check the pressure and add air if necessary.

[Bruce Wrenn]

You could go back with another PVC valve. What I would do, based upon may years of experience, is cut the line, solvent weld in a new valve and add a plastic union to connect back to pump. The union needs to be on the pump side of the valve. This way when it's time to replace seal and impeller end bearing on the pump, you can isolate it from rest of plumbing. FYI, seals are readily available for most pumps, and the bearing is most likely going to be a 6203. Get the 6203-2RS bearing. Don't be afraid of Chinese bearings as that what OEM is now. What is the purpose of the valve anyway? is it just to separate pump from tank, or is it being used as a throttling valve?

[Bruce Wrenn]

Ball valves are so good these days that I can't think of any reason to use a gate valve.

Tom, the only reason to use a gate valve is if it's being used as a throttling valve. With the existing valve being PVC, it's most likely not being used as a throttling valve