Step 4 · Unscrew the Old T&P Valve
Place a large pipe wrench over the hexagonal body of the old T&P valve itself. Position the wrench so you can apply force in a counter-clockwise direction. This may require significant leverage, as the valve is often sealed tightly. Pull firmly on the wrench to break the seal and unscrew the valve completely from the water heater tank. Keep a bucket underneath to catch any remaining water that spills from the opening.