How Rinnai Tankless Units Work

When there is a demand for hot water, the Rinnai unit senses the flow and starts the heating process. This results in hot water that is not limited to what's available in your tank, so you always have clean, hot water when you want it for as long as you need it! When the demand for hot water ceases, the tankless unit shuts down and uses no energy.

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Sequence of operation

  1. A hot water tap is opened such as a kitchen / bath faucet, shower, tub or washing machine
  2. The water flow through the Rinnai tankless water heater detects the call for hot water
  3. The water flow turbine sends a signal to the control board which looks at multiple factors:
    • Incoming water temperature
    • Desired water temperature as set on the temperature controller
    • Calculated difference between the two temperatures
  4. Depending on the calculated incoming and desired water temperatures, the gas flow into the burner assembly is modulated
  5. The electronic ignition sequence begins
  6. Water is heated to the desired temperature as it circulates through the copper heat exchanger providing endless hot water
  7. When the hot water tap is turned off, the tankless water heater sequentially shuts down and is placed in a standby mode pending the next call for hot water


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