Step 7 · Refill and Restart
It is time to return the water heater to service. First, ensure the drain valve at the bottom of the tank is fully closed. Go to the hot water faucet you previously opened and leave it open. Slowly turn the cold water supply valve counter-clockwise to begin refilling the tank. Air will hiss and sputter from the open hot water faucet. Keep the water filling until you have a steady, air-free stream of water coming from the faucet, then turn the faucet off. Meticulously inspect the new T&P valve and discharge pipe connection for any signs of leaks. If everything is dry, return to the electrical panel and switch the water heater's circuit breaker back to the 'ON' position.