Vitoplex 300: low temperature oil/gas boiler

The Vitoplex 300, type TX3A (620 to 2000 kW), is a low temperature oil/gas boiler. There is a reduced mode setting for the single boiler and multi-boiler systems (with the lead boiler) which allows for operation with lower boiler water temperature. Lag boilers of multi boiler systems can be shut down.

Viessmann boilers comply with EN 303 and DIN 4702 and all are CE-designated. They are suitable for installation in sealed unvented heating systems to EN 12828.  

Benefits at a glance:

  • Multi-layered convection heating surfaces for high operational reliability and long service life.
  • Standard seasonal efficiency [to DIN] for operation with fuel oil/natural gas: 90 % (Hs) [gross cv] / 96 % (Hi) [net cv].
  • Optional stainless steel flue gas/water heat exchanger enables the use of condensing technology for higher standard seasonal efficiency [to DIN].
  • Three-pass boiler with low combustion chamber loading, resulting in clean combustion with low emissions.
  • Wide water galleries and large water content provide excellent natural circulation and reliable heat transfer.
  • The integral Therm-Control start-up system replaces the shunt pump or constant return temperature raising facility, thereby saving installation time and costs.
  • Fastfix installation system for rapid and simple installation
  • With walk-on boiler cover – for easier installation and maintenance.
  • Digital Vitotronic control system with communication capability ensures economical and reliable operation of the heating system.
  • Standardized LON BUS for complete integration into building management systems.

The Vitoplex 300 is only suitable for fully pumped hot water heating systems from 620 kW with walk-on boiler cover for easier installation and maintenance. It has an easy to use Vitotronic control unit with a color touchscreen.

A Vitocontrol control panel can be supplied on request. It is equipped with a low-temperature oil/gas boiler as well as a three-pass boiler with multi-layered convection heating surfaces. It is designed for operation with a modulating boiler water temperature with a Vitotrans 300 as a condensing unit.

Vitoplex 300 stands for tested quality: it comes with CE designation according to current EC Directives at a permissible flow temperature (safety temperature) of up to 110 °C to EN 12828.

Vitoplex 300 Specifications


CE designation
Permissible operating pressure
6 bar (= 600 kPa)
Permissible flow temperature
up to 110 °C (up to 120 °C on request)
Flue gas temperature at rated heating output
160 °C
Flue gas temperature at partial load
105 °C
Service interface
Integral Wi-Fi
Height of anti-vibration boiler supports
37 mm
Boiler water content
965 lt - 2315 lt