How does a tankless water heater work?
When a faucet is turned on in the home, cold water flows into the water heater. The flow sensor reads that the cold water has passed through the buffer tank and then signals the controller to switch the system into operating mode. This will cause the ignition to spark and the gas valve to open, and once the gas is supplied to the burner combustion begins. While this is all going on, the controller (or brains of the system) monitors the status of combustion and water usage. The cold water passes through the heat exchanger and becomes hot, and the hot water flows out of the faucet.