What steps are involved in filling and purging air from a new hot water heater installation?

What steps are involved in filling and purging air from a new hot water heater installation?

• A. Open cold line only, start filling, then vent air at hot taps.
• B. Open cold and hot lines, fill tank, vent air at hot taps until steady flow, check for leaks, set thermostat.
• C. Open hot line only after filling, then vent at cold taps.
• D. Close all lines and test for leaks without venting air.

Answer: (B)

Filling and purging air correctly starts with letting water enter the heater through the cold-water inlet while giving air a way out through the hot-water path. Opening both lines ensures the tank and the supply lines fill smoothly and that air isn’t trapped in the system. As you fill, open a hot-water faucet at a distant fixture and keep it open until the water runs out steady with no air sputtering. This venting step is what purges the air pockets that can block flow and prevent proper heating. Once you’re delivering a steady flow, you can check all connections for leaks and then set the thermostat to a safe, energy-efficient temperature (about 120°F). If you skip venting or try to fill from only one line, air can remain trapped, causing noise, uneven heating, or the heater taking longer to deliver hot water.

Filling and purging air correctly starts with letting water enter the heater through the cold-water inlet while giving air a way out through the hot-water path. Opening both lines ensures the tank and the supply lines fill smoothly and that air isn’t trapped in the system. As you fill, open a hot-water faucet at a distant fixture and keep it open until the water runs out steady with no air sputtering. This venting step is what purges the air pockets that can block flow and prevent proper heating. Once you’re delivering a steady flow, you can check all connections for leaks and then set the thermostat to a safe, energy-efficient temperature (about 120°F). If you skip venting or try to fill from only one line, air can remain trapped, causing noise, uneven heating, or the heater taking longer to deliver hot water.