How to Drain a Gas Water Heater

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During winter, we always need hot water for home use. And since electricity is more expensive, many homeowners opt for gas water heaters. However, these units need flushing as regular maintenance at least twice a year.

For that reason, this article will guide you on how to drain a gas water heater.

Gas heaters are prone to rust. So, learning how to drain your hot water tank should be the first thing before purchasing the unit.

Water contains natural minerals, sand, and grit from its source. These minerals settle at the base or around the tank wall when it gets heated. Afterward, they degrade the heater efficiency, and you face higher costs.

What are the Components of a Gas Water Heater?

How to Drain a Gas Water Heater
Gas Water Heater system

Before learning how to drain a gas water heater, it’s good to understand its components for effective maintenance. Let’s dive in;

  • The Gas Water Heater Tank

The tank is made of different materials;

  • The External Steel Jacket

It encloses the tank to protect the inner layers. Usually, the material is heat resistant to protect people from burning.

  • The Internal Tank

It’s a steel tank with a glass or plastic coating on the inner surface to protect the tank from rusting.

  • Insulation Layer

It’s fixed between the external jacket and the inner tank to prevent heat loss. Secondly, it prevents heat from getting to the external jacket for people’s safety.

  • Dip Tube

The dip tube extends to the lower part of the tank.  Its purpose is to supply cold water for heating.

  • Hot Water Discharge Pipe

It directs hot water to the supply pipes for home use. It’s usually shorter than the dip tube and located at the top of the tank.

  • Sacrificial Anode

It runs from the top of the tank to the bottom. The rod is made of magnesium or aluminum material that draws ions from the water to prevent the tank and pipes from rusting.

Read: Who buys used hot water heaters near me?

How to Drain a Gas Water Heater
Modern heater system
  • Pressure Valve

The pressure valve is located at the top of the tank. Its purpose is to relieve excess pressure build-up from the tank for efficiency.

  • Drain Valve

It helps to drain water from the tank during maintenance or repair. It’s the valve that flushes out the built-up sediments from the tank.

  • The External Piping

There are two main pipes connected to the tank. Take a look;

  • Cold Water Pipe

It connects the dip tube at the bottom of the water tank. The purpose of the cold-water pipe is to supply cold water to the heater, as the name suggests.

The cold-water pipe has a shut-off valve that you may use to prevent cold water from getting into the tank.

  • Hot Water Pipe

It connects the hot water discharge pipe to supply hot water for home use. The hot water pipe has a shut-off valve too.

  • The Gas Burner

The gas burner is located underneath the tank. It has several components;

  • Gas Line

It supplies the gas to the regulator. The line is made of steel or copper pipes. Additionally, it has a gas shut-off valve.

  • Pilot Light

It automatically lights the burner when the thermostat commands it. It has a component known as a thermocouple that converts heat to an electrical impulse.

  • Thermostat

It regulates the water temperature by turning the unit on or off.

  • The Exhausts Flue

It’s located at the centre of the inner tank and runs from the gas burner to the house’s chimney or the outlet vent. This pipe directs exhaust gases out of the burner.

Additionally, it also transfers heat to the water to enhance efficiency.

Read: Baseboard heater bleeder valve replacement

Steps How to Drain a Gas Water Heater

Step 1:

Turn the gas shut-off valve to “pilot position.” The flame will continue to burn in the pilot position until the gas in between the valve and the burner is consumed.

Step 2:

Turn the cold water shut-off valve clockwise to cut the cold-water supply into the tank.

Step 3:

Allow the tank to cool for around two hours. The tank holds over 50 gallons of water. To avoid wastage, you can use it to water the plants.

Step 4:

Connect a garden hose to the drain valve and direct it to the farm or a collecting tank.

Step 5:

Turn the drain valve and let the water completely drain. At the drain location, you’ll notice milky water with small sediments.

Step 6:

Open the cold-water valve to flush the tank. Allow the water to run for around 10 minutes while flushing until it turns clear.

Step 7:

Close the drain valve and disconnect the garden hose.

Step 8:

Fill the tank with cold water and turn the gas regulator valve to “on position.” Ensure the pilot light is working and the thermostat is well set.

Read: Miniature heat pump

FAQs on Gas Water Heaters

How Do Gas Hot Water Systems Work?

Cold water enters the system through the dip tube. The tube is extended to the lower part to allow dense water to settle at the bottom without mixing with already heated water. The gas burner beneath the tank heats the dense water, and once the temperature increases, it rises to allow more cold-water in. On the top of the tank, a hot water discharge pipe directs heated water out of the tank for home use.

At the middle of the tank, an exhaust flue runs from the gas burner to the top and is later directed to the chimney to allow exhaust gases out. It has a spiral metal baffle that transfers heat to the water as the hot gases leave. This mechanism enhances efficiency. The gas burner is controlled by a regulator assembly which consists of the thermostat and the pilot light. The system regulates the temperature by turning the gas burner on and off.

How Long Does it Take to Drain a 50 Gallon Water Heater?

It can take around 20 to 60 minutes, depending on the diameter of the drain valve and the type of hose you use. Open the pressure valve or disconnect the water supply pipe to allow more air to operate faster.

How Often Should a Water Heater Be Flushed?

You should be ready to drain a gas water heater tank every six months. If you use hard water, you may need to flush it regularly. 

Read: How to remove air from a closed loop system