Final answer:
Before opening a water heater's drain valve, you must turn off the gas supply, disconnect the electrical power, close the pressure relief valve, and drain the hot water tank. All Options are correct.
Step-by-step explanation:
Before opening a water heater's drain valve, you must follow these steps:
Turn off the gas supply: This is important as it prevents gas leakage or potential fires.
Disconnect the electrical power: This ensures that there is no risk of electric shock when draining the water heater.
Close the pressure relief valve: This allows the system pressure to stabilize and prevents excess water from flowing out during the draining process.
Drain the hot water tank: Finally, you can open the drain valve to remove any residual water from the tank.
Before opening a water heater’s drain valve, it is important to first turn off the gas supply or disconnect the electrical power to the unit, depending on whether it is a gas or electric water heater.
This safety step prevents any heating elements from turning on while the tank is being drained, which could damage the unit or pose a safety risk. Additionally, ensure that the tank temperature is not too high to prevent scalding during draining, and that the water pressure has been relieved.