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How Tankless Water Heaters Work

How Tankless Water Heaters Work

 A tankless Rinnai water heater works by heating water on demand as it flows through the unit, rather than storing and continuously heating a large tank of water like traditional water heaters.

Here are the steps of how a tankless Rinnai water eater works:
  1. When a hot water tap is turned on in the house, cold water enters the tankless water heater through an inlet pipe at the bottom of the heater.
  2. The water flow is detected by a flow sensor, which signals the unit to start heating the water.
  3. A flame ignites and heats the heat exchangers allowing warm water to pass through to a secondary heat exchanger. (in higher efficiency models)
  4. The heated water exits the unit and travels through the pipes to the faucet or appliance where hot water is needed.
  5. When the hot water tap is turned off, the tankless water heater stops heating water and goes into standby mode until it is needed again.


One advantage of a tankless Rinnai water heater is that it can provide an endless supply of hot water, as long as the demand does not exceed the unit's flow rate. Another advantage is that it can be more energy-efficient than traditional tank water heaters, as it does not continuously heat water when it is not needed.

Choosing the right size tankless hot water heater requires careful consideration of your household's hot water needs, temperature rise, unit flow rate, efficiency rating, and household size. Visit our previous blog to help make an informed decision and enjoy the benefits of a constant supply of hot water while saving money on your energy bills.


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