auroSTEP Drainback solar system

auroSTEP Drainback solar system

Reasonable and environment-protecting - auroSTEP solar water heating system with drainback feature
  • Pump control according to demand
  • Anti-block system for the solar circuit pump
  • Absorber efficiency: 95%

Overview Features and benefits Downloads

auroSTEP Drainback Solar System


auroSTEP solar water heater is manufactured in a German plant which is one of the most modern plants in Europe, with exclusive Vaillant components, with maximum quality, robustness and reliability.

Our system is innovative and different compared to competitors´ products – in its function and its manner of installation. It is a well-outlaid drainback system with high efficiency. In the interior of the installation we find a solar liquid (mixture of glycol and water) and air, therefore there is no need for determined hydraulic components as for example expansion vessel, exhaust fan, manometer…etc. as there is practically no pressure in the system.

When the central control unit puts the integrated pump in function, it begins to transport the solar liquid from the serpentine of the accumulator through the tubes to the solar panels where it is heated and sent back to the accumulator to heat the stored sanitary water. During standby the solar liquid is stored in the tubes at the bottom of the system, the collector contains nothing but air. Therefore there is no loss of efficiency due to stagnation of the system, different from pressurized solar systems.

Our auroSTEP range

auroSTEP plus 1.150/2.250/3.350:

  • Solar panels; auroTHERM flat plate collectors VFK 135 D & VFK 135 VD
  • Storage;150/250/350 litres (one & two heat exchangers - monovalent/bivalent)
  • Control unit
  • Safety valve
  • Mounting frame for collector


Advantage at a glance:

  • Solar water heating system with only 3 components: storage unit with integrated solar pump unit and solar control – all pre-assembled, flat plate collectors and tubing
  • Well defined system combinations for standard installations – no detailed calculation required
  • Solar system in 3 versions: auroSTEP plus 1.150, auroSTEP plus 2.250 and auroSTEP plus 3.350
  • Storage volumes 150, 250 and 350 litres
  • Pre-filled drainback system – no filling procedure for the solar circuit needed during initial operation
  • Quick and easy installation: “plug ‘n flow”
  • High quality for an attractive system price – best value for money
Differential temperature control for activating the solar circuit pump Pump control according to demand
Filling/operating mode for the solar circuit pump Anti-block system for the solar circuit pump
Calendar for automatic switching to daylight saving time Absorber efficiency: 95%
Easy system choice, small number of components to be installed, less interfaces mean low opportunities for failures Operational reliability, no customer complaints and no additional goodwill services
Quick and easy initial operation with standard settings, but customising of settings possible Simple checking of system parameters, error code feedback of the user interface, programming of the control possible
No need to select the right pump speed – pump is always working at the best speed Presentable and attractive top quality product, suitable even for the (extended) living space
Reliable solar system also at high solar irradiation and high temperatures It is possible but not necessary to optimise the solar system for maximum solar gain or top comfort according to the specific needs & preferences of the user
System mode of operation and specific values at a glance, programming of comfort time slots possible Low electric energy consumption, pump speed (and noise) is always as low as possible