Pro tip: Don’t forget to seal all thread connections with plumbing tape or pipe dope. Close the new drain valve and all the faucets you opened, turn on the cold water and let the tank fill.

Install the New Valve You probably have a 3/4-in. pipe leading to and from the leaky valve. Buy a threaded replacement ball valve; it’s a far better choice than the older gate-style valve.

Use iron pipe nipples to connect the solenoid valve to the PVC fittings on the air tank and barrel. Apply pipe-thread sealant to prevent leaks. Complete Connections ...