The Stiebel Eltron Electric Tankless Water Heater:
How does it Work?

The Stiebel Eltron electric tankless water heater is a marvel of technology and engineering - overflowing with technology yet packaged in an intelligent, simple design. It heats water entirely on demand, only when it is needed.

When a hot water faucet is turned on and the water begins to flow, a sophisticated flow sensor detects that hot water is being demanded and turns the water heater on. Instantaneously, a series of sensors gather information about the flow rate of the water and the incoming water temperature. This information is sent to a microprocessor which calculates the amount of power needed to heat the water to the temperature set point. The water flows through the internal heating modules and exits the unit at the desired temperature. The start-up process takes a couple of seconds. A convenient thermostatic control and digital display on the front of the unit allows the homeowner to select an output temperature of between 86 and 125F (30 to 52C).

The sensors continue to monitor the water flow rate and incoming water temperature as long as the water is running. They send constant and continuous data to the microprocessor so power to the heating elements can be modulated in accordance with changes in incoming flow rate and temperature. If, for instance, the flow rate increases because a second demand for hot water in the home is initiated, the unit will increase its power output to maintain a consistent and precise output temperature.

The tankless water heater will remain on until the hot water faucet is closed. As soon as the flow sensor detects that water has stopped flowing, the power to the unit is completely turned off.

All Stiebel Eltron Tankless Water Heater water heaters are manufactured in Germany in one of the world's only ISO-9001 certified tankless water heater manufacturing plants, by a company that has been around since 1924! .

Please see the internal view of the Stiebel Eltron Tankless Water Heater (Tempra 24 model shown) below for more details. All of the models utilize the same parts and technology, but have varying sizes and numbers of heating modules.

Electronic Control Module
Sophisticated microprocessor-controlled electronics adjust the power output of the heating modules based on flow rate and incoming water temperature to precisely regulate the output water temp.

Heating Module
The muscle of the system! A series of very high output heating modules (up to 3, depending on model) are used to heat the water as it passes through the heating chambers of the water heater. The heating chambers are manufactured with copper - no cheap plastics here!

Flow Sensors
Sophisticated flow rate sensors deliver important data to the microprocessor on a continuous basis - this data is used by the microprocessor to calculate the power level of the heating modules that is necessary to heat the water to the set temperature.

Safety Thermal cut-off
Safety first! Each heating chamber is protected by thermal limit switch, a back-up safety feature that will automatically turn off the heating module if a potentially unsafe output water temperature is reached. This reduces the risk of scalding injuries for children and the elderly, and protects the unit from damage if the microprocessor-based thermostatic control fails.

Digital Display
Set it and forget it - use the simple dial control to raise or lower the temperature setting. A digital display indicates the current temperature setting. The temperature can be set at any level between 86F (30C) and 125F (52C). Convenient power-on indicator light.

Temperature Sensors
Working in conjunction with the flow sensor, a series of temperature sensors deliver important data to the microprocessor on a continuous basis so that the unit can acurately maintain the set output water temperature.

Wiring Block
Convenient terminal blocks are provided to ensure a quick, simple, and safe installation.

Inlet Water Filter
The inlet water pipe includes a small screen filter that ensures that no debris is able to enter the system. This filter should be periodically cleaned for optimal flow performance. In most cases, this need only be done once every few years, but the exact frequency will depend on your water quality.