The controller of the eTherm S can control one phase of the eTherm C9, and is thus able to act as an energy manager to regulate the excess power and modulate the eTherm C from 0-3000 W.

The eTherm P/C must not be operated directly with potable water. However, the stations can be connected to potable water storage tanks with internal heat exchangers. In the case of bivalent drinking water storage tanks, the heat exchangers should be connected in series.

The eTherm P/C can monitor the storage tank temperature by means of a storage tank temperature sensor (not included in the scope of delivery) and thus serve as an emergency heater even without external energy management. If the storage tank temperature falls below a threshold value (adjustable), the stations start heating. Both the eTherm C and the eTherm P have the option of storage tank reheating to ensure a minimum storage tank temperature.

Products of the eTherm family were developed for PV surplus power use. The stations use only surplus electricity. This means: the eTherm products do not start until all household consumers, the battery storage and, if applicable, the charging station for the electric car have been served and surplus electricity is still available.

For the electrical connection, two additional installation contactors are set as additional auxiliary relays. Usually, a 1-phase and a 3-phase installation contactor must be installed here. The first phase of the cartridge heater is thus connected to the 1-phase contactor, the two remaining phases of the cartridge heater are connected to the 3-phase contactor. It is important to correctly assign the phases to the controller! The single-phase contactor must be connected to the controller as consumer 1 and the second contactor with 2 phases as consumer 2. Now 12,000 watts of continuously modulating power are available.

By turning 45°, the gravity brake integrated in the ball valve can be set up manually.

The eTherm P is designed to maximize self-consumption. With this background, the eTherm is also able to activate additional consumers if required. This allows the eTherm to generate higher self-consumption with the help of the heat pump via a switching contact. If a SG-ready connection is available, the eTherm can be switched over it and thus takes part in the control energy market.

The eTherm C relies on external energy management for its operation. The Fronius Ohmpilot or the AC Thor 9S are representatives of the modulating energy managers. This makes it possible to control the eTherm C continuously from 0-9000 W.
In this process, the smart meters of the energy managers measure the excess power at the feed-in point and attempt to regulate the feed-in to zero.

The eTherm P/C can be optimally connected to existing systems. For this purpose, the stations are connected at the very top (forward) and at the very bottom (return). If there are no free connections at the storage tank, the stations can also be connected by means of T-pieces parallel to existing heat generators.

The eTherm C requires an energy manager for intelligent PV surplus utilization. The following combinations are possible:

• Fronius Ohmpilot (0-9000 W modulating)
• MYPV ACThor 9S (0-9000 W modulating)
• Solaredge Smart Energy Hot Water Controller (0-9000W modulating)
• powerReducer-Set eTherm C3 (0-3000 W modulating)
• SMA Sunny Home Manager 2.0 (3-stage switching)
• Solar-Log Smart Relais Station (3-stage switching)
• Solarwatt EnergyManager (3-stage switching)

The eTherm P can control up to two additional consumers by means of external auxiliary relays. With the external consumers, stepless power modulation up to 12 kW can be achieved. The cascade of eTherm P and eTherm C offers a particularly effective combination. Here, the entire output is converted into heat in two hydraulic stations and the storage tank can thus be loaded in layers with a constant target temperature.

The eTherm C executes commands given to it by an energy manager. If the wallbox is able to communicate with the energy manager, the system can usually be freely programmed.

An incorrect flow direction during flushing / cleaning can lead to the cone of the gravity brake being pressed too deeply into the seat and not being released again by itself.

The main task of the eTherm P is to use own produced PV surplus electricity (current measuring sensor included in the scope of delivery) for heating of a buffer or potable water storage tank.

The station has various control options, such as 0-10 V or SG-ready, and also various selector functions that make the station flexible to use, including the following selector functions:

• internal reheating -> emergency heating function when the temperature falls below a minimum storage tank temperature.
• external reheating -> storage tank temperature monitoring, control external heat generator if temperature drops below minimum value
• external consumer -> extension of the maximum convertible power by up to two additional electrical consumers to increase self-consumption, control of a heating rod, a heat pump or any electrical consumer
• inverter -> limitation of the inverter power, for example to comply with the 70% feed-in regulation.

The eTherm S (self-sufficient solution -> plug and play solution for small storage tanks) has a heating rod that is modulated by the controller according to the surplus. Due to the design (heating rod in the storage tank), this system is particularly suitable for small drinking water storage tanks.

The eTherm P (self-sufficient, hydraulic station for PV systems from approx. 4 kWp and storage tank from 400 l) has
a coordinated system of surplus measurement and power modulation for constant target temperature loading of the storage tank.

The eTherm C (for PV systems from 8 kWp and storage tanks from 500 l) is a powerful hydraulic station for target temperature loading of the storage tank. The eTherm C relies on external energy management, as described above. Representatives of the switching energy managers are for example (switching 3000W, 6000W, 9000W) Solarwatt, Solarlog, Solaredge, SMA etc.

• In solar thermal energy, collectors convert solar radiation into heat, which is transferred through a water-glycol circuit to a hot water or buffer tank.
  
• In photovoltaic modules, solar radiation is converted into electrical voltage, which is fed into the building’s power grid through an inverter.
  
• Photovoltaic power can be converted into heat by Power to heat modules like the tubra®-eTherm. It can also be stored in buffer tanks and used for heat applications.

• The max. permissible temperature of the medium in the solar flow is short-term at 140°C
• In the solar return with the pump, the max. permissible medium temperature is at 110°C.

The selection of eTherm is sometimes based on the power of the installed PV system and its peak power in kWp.

• 3 kW
• 9 kW
• 12 kW
• 18 kW
• 27 kW
• 36 kW

The eTherm is always connected to the electrical system as the last consumer before the bidirectional meter. The direction arrows on the measuring clamps must be set so that they point in the direction of the consumers. The correct polarity on the sensor module must be observed.

• ÜSTA stratification loading set: layered, optimum accumulator loading via single or double switchover
• heat meter set