How Does Gas Water Heater Work?

How Does Gas Water Heater Work? This question has been frequently asked by homeowners today, and we will be answering it today. Most homes have the common gas water heater, which can operate faultlessly for many years with just a little maintenance. Although most homeowners still prefer gas water heaters, tankless heaters that heat water only as needed are growing in popularity. So, how does gas water heater work?

A gas water heater works according to the physics principle of convection, specifying how heat rises. In the case of a water heater, the cold water is forced into the tank through a cold water supply tube to maintain a steady flow. A gas burner is situated beneath the sealed tank, heating the cold, thick water at the bottom. The hot water discharge pipe draws the rising water from the tank as it gets hotter, so it can be used wherever hot water is needed. Since the hot water discharge pipe’s function is to channel off the hottest water, which is located at the top of the tank, it is much shorter than the dip tube.

How Does Gas Water Heater Work?

Depending on the season, the water entering your home travels through a network of pipes and is typically cold or cool. It would help if you had a water heater to have enough warm water to run your dishwasher or washing machine, take a hot shower or bath, etc.

The majority of homes have common fixtures like water heaters. They resemble large metal cylinders or tall drums frequently kept in the basement or laundry room. Some intriguing characteristics of more recent designs include fully doing away with the tank in favor of water-on-demand.

Two distinct processes operate in a gas water heater to provide your hot water. The energy for heating is provided by the gas system, which is connected to a propane tank or a utility company. The plumbing system flows cold water into the tank and hot water out of it, and it has a safety feature to stop explosions.

Increase the gas, so the flame burns hotter to raise the water’s temperature, or decrease the flow rate, so the water spends more time in the heat exchanger. However, be careful not to reduce the flow rate too much, or the gas won’t turn on.

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The Heating Cycle

The thermostat, housed inside the tank, tracks the temperature of the water and alerts the need for heat when it drops below the predetermined level. 

The gas valve, which also receives the signal, opens while the ignitor, if the model has one, also receives the signal and starts to produce sparks. If the model has a standing pilot, the gas valve opens when the signal is received, allowing the pilot to ignite the gas.

The water heater operates precisely like a pan on a stove after the gas ignites until the temperature exceeds the cutoff point, at which point the gas is turned off. Turning the dial on the gas control can modify the cut-in and cut-out temperatures. The majority of models feature A, B, and C-labeled preset settings. By selecting the least expensive option, A, you can conserve energy.

Cold Water Supply Pipe And Hot Water Discharge Pipe

Two water pipes—a cold water supply pipe and a hot water discharge pipe—are attached to the top of the tank.

Cold Water Supply Line: A shutoff valve manages the cold water supply line that delivers the cold water to the tank. It’s critical to be aware of the location of the water supply shutoff valve so you can close it when maintenance is necessary.

Since the pressure from the cold water entering the tank keeps the hot water flowing outward, turning off the cold water supply effectively stops all water flow. A blue handle typically distinguishes the cold water supply shutoff valve.

The Hot Water Discharge Pipe: which supplies hot water to all of your sinks, tubs, showers, and appliances that require hot water, is the operational end of the water heater. A shutoff valve, frequently distinguished by a red handle, may also be present in the hot water discharge pipe.

Gas Regulator And Burner Assembly

A pipe with its gas shutdown valve is connected to a gas pipe made of steel black pipe or copper tubing to supply the natural gas or propane that heats the water. It’s crucial to know the location of this gas shutoff valve so you can turn the gas off in an emergency or to conduct repairs. 

A gas regulator with a thermostat for the water heater receives gas from a gas line. This valve also delivers gas to the pilot light, which ignites the burner when the regulator valve and thermostat signal it through a tiny secondary tube.

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The gas burner assembly, which you can access through a metal panel on the bottom of the water heater’s outer casing, receives gas from the gas regulator. The gas burner and the pilot light are parts of this assembly. The water heater’s proper and energy-efficient operation depends on the pilot light and burner adjustment.

The gas flames ought to be about half an inch high with blue tips (yellow flames indicate dirty burner jets or an improper air mixture). A thermocouple, a tiny valve that transforms heat into an electrical impulse, is an essential part of the pilot light. 

This part is a flame sensor on more recent water heaters. Since it detects the presence of the pilot flame and stops gas from flowing to the burner if there is no pilot flame to ignite it, the thermocouple or flame sensor is a crucial safety feature. A thermocouple or flame sensor replacement is a simple task.

Flow-Through Hot Water Heater Power Supply

Most continuous flows through water heaters are connected to your home’s power supply to power the sparking igniter, which ignites the gas.

However, some flow-through water heaters employ the power for ignition produced by the water passing through a small water turbine (see graphic).

Finally, certain flow-through water heaters operate solely on batteries.

In that, they will continue to function (an immediate gas geyser will work) even if there is a power outage. The turbine and battery-driven systems have a clear benefit over the connected counterparts.

The physical and financial drawback of the turbine-powered version is that it is both more expensive and physically larger than a comparable plug-in model.

Components Inside A Water Heater

Let’s quickly review the parts of your water heater that cooperate to make your morning shower so pleasurable:


A heavy metal tank with a water-protective liner that can hold 40–60 gallons (151–227 liters) of hot water at a pressure of between 50–100 pounds per square inch (PSI), which is within the range of a typical residential water system. 

An insulating substance, such as polyurethane foam is applied to the tank’s exterior. A decorative outer shell and perhaps an additional insulating blanket are placed on top.

Shutoff Valve

Water flow into the water heater is stopped by the shutoff valve. It’s not a part of the heater outside and above the appliance. The hot water can leave the water heater through the heat-out pipe, suspended near the top of the tank’s interior.

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A thermometer and temperature-controlling device is a thermostat. Some electric water heaters may have a separate thermostat for every element.

Heating System 

Electric water heaters have heating elements inside the tank to heat the water. Gas water heaters use a burner and chimney system instead.

The Drain Valve

The drain valve is located near the bottom of the exterior housing, the drain valve makes it easy to empty the tank to replace the elements, remove sediment or move the tank to another location.

Sacrificial Anode Rod 

Made of magnesium or aluminum with a steel core, the sacrificial anode rod is suspended in the water heater tank to help retard corrosion. 

Water Heater Safety Features

Dual-element electric water heaters provide several safety features like gas water heaters. A switch known as a “high-limit” switch will immediately turn off the power to both components if the water level within the tank rises to an unsafe level. 

A pressure relief valve normally placed against the side of the tank will open and discharge water to stop the tank from exploding if the high-limit switch fails to work.

Dual-element heaters, like their gas-powered counterparts, have a drain cock at the bottom of the tank to remove sediments and an anode rod that progressively corrodes over time to extend the tank’s life by filling small rust spots that form along the internal walls of the tank.

Troubleshooting Common Problems

Check the home’s breaker box for a tripped breaker first if the heater is no longer producing hot water. You might need to reset the heater’s thermostat if all the breakers are on. 

A reset button is only on the thermostat that regulates the upper element. Press the button, then wait for the water to warm up for around 10 minutes.

If the issue persists, the heater probably has a broken thermostat or heating element. Check the lower thermostat and heating element if the heater only produces a limited amount of hot water. If a voltmeter doesn’t show any voltage, check the thermostat and replace it. Replace the heating element if the voltage is detected.

Conclusion On How Does Gas Water Heater Work? 

By becoming familiar with the fundamentals of your hot water heating system, you are putting yourself and your family in a position to handle the unexpected. We often take hot water for granted, and most of us use it daily.

Finding the fastest fix for any hot water issues you could have is a smart idea. You will be better prepared to choose wisely in the future should you invest in one of these fantastic inventions if you take the time to educate yourself about water heaters. We hope we have answered your question on how does gas water heater works.