Flow sensing in tankless water heaters

Tankless water heaters are becoming a widely popular solution for water heating needs. The availability of hot water on demand and the perceived limitless supply of hot water make these types of water heaters much more attractive than traditional tank water heaters. These water heaters also provide long term energy savings since energy is used only when there is a demand for hot water.

In order to effectively heat the water when there is a demand, a sensor is needed to detect the flow of water.

Flow switches
A flow switch is used to detect the presence of water flow and turns on the system to heat the water. Whenever there is a hot water demand, a reed sensor within the tankless water heater identifies the demand and initiates the heating process. This sensor monitors the presence of water flow while two other sensors measure the incoming and outgoing water temperature. This information is transmitted continually to a microprocessor controller which determines the precise amount of power to send to the heating elements to heat the water to the desired temperature.

Flow sensors
A flow sensor performs the same function but provides the added benefit of measuring the rate of water flow. Flow sensors are also used in tankless water heaters. In Europe and other regions, pressure pump showers with flow sensor-based utility metering technology are widely used. The pressure pump creates pressure for the shower when water flow is sensed, which helps conserve water.

Many multi-unit apartment buildings are equipped with water submetering systems that employ flow sensors to measure water usage in individual apartments. Even in some individual homes, submetering systems with flow sensors are being installed to monitor water usage at various locations throughout the home.

The lowering costs of wireless communication technology helps to make these systems more economically feasible.

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