A gas tankless water heater is another type of tankless water heater that uses natural gas or propane as its fuel source to heat water on-demand. It operates in a similar fashion to an electric tankless water heater, but with a different heating mechanism. Here’s how a gas tankless water heater works:
- Water Flow Initiation: When a hot water tap is opened or a hot water appliance is activated, cold water enters the tankless water heater.
- Activation: Sensors in the unit detect the water flow and trigger the ignition process.
- Combustion: The gas burner inside the tankless water heater ignites, creating a flame.
- Heat Exchange: As water passes through the unit, it flows over a heat exchanger. The heat exchanger is heated by the gas flame, transferring the heat to the water.
- Temperature Control: The gas flow and flame intensity are adjusted to achieve the desired hot water temperature. Most gas tankless water heaters have temperature control knobs or digital displays for setting and maintaining the desired temperature.
- Hot Water Distribution: The heated water exits the tankless unit and travels through the plumbing system to reach the hot water tap or appliance where it is needed.
- Shut-off: When the hot water tap is closed or the hot water demand ceases, the flow of water stops, and the gas burner is turned off.
Some key features and benefits of gas tankless water heaters include:
- High Flow Rates: Gas tankless water heaters can provide a higher flow rate of hot water compared to electric tankless water heaters, making them suitable for larger households with higher hot water demands.
- Efficiency: Gas tankless water heaters are energy efficient because they only heat water as it is needed, minimizing standby heat loss. They can achieve high energy efficiency ratings (such as Energy Factor or EF ratings) depending on the model.
- Endless Hot Water: Similar to electric tankless water heaters, gas tankless water heaters can provide a continuous supply of hot water as long as there is a gas supply and water flow.
- Quick Recovery: Gas tankless water heaters have a rapid heat recovery time, allowing them to provide hot water continuously even during periods of high demand.
- Lower Operating Costs: Gas is often less expensive than electricity, so operating costs for a gas tankless water heater may be lower compared to an electric unit, depending on local utility rates.
It’s important to note that gas tankless water heaters require proper venting for exhaust gases and may have specific venting requirements based on local building codes and regulations. Additionally, professional installation and maintenance by a qualified technician are crucial for the safe and efficient operation of a gas tankless water heater.
How gas tankless water heater works
A gas tankless water heater works by heating the water directly as it flows through the unit, without the need for a storage tank. Here is a step-by-step explanation of how it operates:
Water Flow Initiation
When a hot water tap is opened or a hot water appliance is activated, cold water enters the tankless water heater.
Activation
The flow of water triggers sensors within the unit, signaling the ignition process.
Ignition
A gas burner, typically fueled by natural gas or propane, ignites to create a flame. The ignition can be initiated by an electric spark or a pilot light, depending on the model.
Gas Tankless Water Heater Combustion
The gas burner generates a controlled flame that heats the heat exchanger—a coiled or finned metal component inside the unit. The combustion process occurs within a sealed chamber to ensure safety and efficient heat transfer.
Gas Tankless Water Heater Heat Exchange
As water flows through the heat exchanger, it circulates around the hot metal surface. The heat from the burner’s flame is transferred to the water through the heat exchanger, raising the water temperature.
Temperature Control
The gas flow and flame intensity can be adjusted to regulate the water temperature. Gas tankless water heaters often have temperature control knobs, digital displays, or advanced controls to set and maintain the desired hot water temperature.
Hot Water Distribution
The heated water exits the tankless unit and travels through the plumbing system to reach the hot water tap or appliance where it is needed.
Shut-off
When the hot water tap is closed or the hot water demand ceases, the flow of water stops. The gas burner is then turned off, and the tankless water heater enters a standby mode until the next hot water demand.
It’s crucial to follow safety guidelines and adhere to local building codes when installing a gas tankless water heater. Adequate venting is required to exhaust combustion gases safely outside the building. Venting options can include direct venting, where air is drawn from outside for combustion and exhaust gases are vented outside, or power venting, which uses a fan to facilitate venting.
Gas tankless water heaters should be installed and serviced by a qualified professional to ensure proper operation, gas supply connections, venting, and safety measures. Regular maintenance, such as cleaning the heat exchanger and checking gas pressure, is also recommended to keep the unit running efficiently and safely.
