CHAUFFAGE FRANCAIS Stelios 250 L Benutzerhandbuch Seite 38

The compressor draws low-temperature, low-pressure refrigerant vapour from the evaporator
and increases the pressure and temperature of the vapour considerably. The refrigerant then
exchanges heat with the water in the water tank and becomes liquid. The water continues to
absorb the heat and the temperature increases. The high-pressure liquid passes through the
throttling device to reduce the pressure and temperature considerably. Finally, the fan draws air
through the evaporator and the cold liquid refrigerant absorbs the heat from the air to become
vapour again. The refrigerant operates continuously in the manner described above in order to
heat the water.
Fig.1 Working principles of air source heat pump water heater
2. Operating principles of electricity-assisted heating
The electrical resistance transfers electrical energy into thermal energy, which the water absorbs
continuously and which increases its temperature. When the temperature reaches the set
temperature, the temperature control devices (located on the printed circuit board) automatically
cut off the power supply, and the electric heater stops working. If dry-heating or overheating
occurs, the protection device, which is not self-resetting, switches off immediately to ensure
protection.