Refill, Light Pilot, and Test Water Heater

What happens here

Slowly open the cold water shut-off valve to refill the water heater tank. While the tank is refilling, open a hot water faucet in a nearby sink to allow air to bleed out of the hot water lines. You'll hear sputtering and see air mixed with water until a steady stream of hot water flows, indicating all air has been expelled. Check the newly installed T&P valve and the drain valve for any leaks. With the tank full, re-engage the gas supply by turning the gas valve to 'On'. Push the pilot button down and light the pilot light, holding it down for a period (e.g., 30-60 seconds) until the thermocouple heats up and keeps the pilot lit. Once the pilot stays lit, turn the dial from 'Pilot' to 'On', and the main burner should ignite, beginning to heat the water.

Goal: Restore full functionality to the water heater and ensure proper operation.