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How Does a Tankless Water Heater Work?

Written by Hanna Plumbing & Heating / May 27, 2022

Tankless water heaters deliver hot water instantly when you turn on your shower or faucet. How does it do this? It may seem like magic but it’s not.

1. When a hot water tap is opened, the tankless water heater detects the flow

2. The flow sensor activates to determine the amount of hot water needed

3. The igniter activates

4. The gas control valve opens to supply the correct amount of gas

5. The burner ignites providing a flame to heat the water

6. Cold water passes through the heat exchanger

7. The unit determines the outgoing set temperature and adjusts the flame to heat the water

8. Desired hot water amount is delivered to the faucet

When you’re ready for a new water heater, call Hanna at (319) 377-2809 or contact us online and we’ll help you determine if a tankless water heater is right for you.


Check out this video from Navien to see the process in action:

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