Vitocrossal 300 CR3B - the most powerful gas condensing boiler

Benefit from these advantages:

  • Converts up to 98 percent of the energy used into heat
  • Stainless steel Inox-Crossal heat exchanger ensures high operational reliability and a long service life
  • Smooth stainless steel heat exchanger surfaces create self-cleaning effect
  • Alternatively with ELCO or Weishaupt pressure-jet gas burner
  • Two return connectors for hydraulic connection optimised for condensing technology

Single boiler systems up to 1400 kW

The Vitocrossal 300 CR3B is a gas condensing boiler delivering an output of 787 to 1400 kW. As a single boiler system, it is Viessmann's most powerful heating centre. This makes it just as suitable for residential complexes as for local heating networks, larger public and commercial buildings and industrial plants.

The Vitocrossal 300 is supplied with a pressure-jet gas burner from either ELCO or Weishaupt. The design of the heat exchanger in the Vitocrossal 300 enables high output levels, yet retaining modest dimensions and a low weight. To facilitate handling, the condensing boiler can be delivered in two sections.

Convenient and highly capable control unit

Safe operation of the system is ensured by the Vitotronic 300 control unit with communication capability. Up to four boilers can be controlled. The plain text and the backlit display with its integral diagnostic system make the unit easy to use.

Integration into building management systems is possible. The TeleControl system with the Vitocom and Vitodata is available for remote monitoring via internet.

Vitocrossal 300 gas condensing boiler, type CR3B

Vitocrossal 300 gas condensing boiler, type CR3B

The Vitocrossal 300, type CR3B is the top product among the floorstanding gas condensing boilers, available from 787 to 1400 kW.

As a single boiler system, it is the most powerful condensing boiler in Viessmann's comprehensive range. This makes it just as suitable for residential complexes as for local heating networks, larger public and commercial buildings, and industrial systems.

Advanced condensing technology

The design of the Inox-Crossal heat exchanger surfaces enables the output of the Vitocrossal 300 to be increased to 1400 kW while maintaining moderate dimensions and low weight. In addition, the split design of the heat exchanger module/combustion chamber module facilitates insertion.

The highly effective heat transfer and the high condensation rate enable standard utilization rates of up to 98 % (Hs). These high standard efficiency levels are achieved by the crossflow principle of heating gas and boiler water, as well as the intensive swirling of the heating gases through the heating surface.

With the Vitocrossal 300, the second return connection enables a hydraulic connection that is particularly favorable for the use of condensing technology.

The Vitocrossal 300 gas condensing boilers are available ex works with ELCO or Weishaupt forced draught gas burners.

Convenient and powerful Vitotronic control unit with color touch display

Convenient and powerful Vitotronic control unit

The Vitotronic control unit with large color touch display allows quick commissioning using the assistance function as well as simple operation. The boiler can be connected directly to the internet via the integrated LAN interface for remote monitoring. The Vitosoft 300 service tool communicates directly via WLAN. Energy consumption can be visualized transparently via the control unit's energy cockpit.

Product cross-section


Output (kW)
787 to 1400 kW
Standard seasonal efficiency [to DIN]
98 % (Hs) [gross cv] / 109 % (Hi) [net cv]
Energy efficiency class
Natural gas E, LL and LPG
Application range
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Large residential buildings, commerce, municipal offices, new build and modernisation projects
High performance Vitotronic 300 control unit, can regulate up to four boilers with modulating boiler water temperature, and systems with one or two heating circuits with optional mixer.
DHW heating
Additional DHW cylinder(s) required, resulting in a high level of DHW convenience
Additional features
Alternatively with ELCO or Weishaupt pressure-jet gas burner


A perfect match – System technology

"The whole is greater than the sum of its parts". Following this philosophy, Viessmann supplies more than high quality, reliable and effective heating components. In fact, all products are part of a matching total concept, where all components complement one another. After all, only perfect interaction between all system components can draw out the maximum potential of our innovative leading technology.

Viessmann system technology incorporates everything you need for a reliable and economical heating system: From the Vitotronic control unit with wireless remote control, powerful Vitocell DHW cylinders for the highest DHW convenience, right up to high grade solar thermal systems for cost effective central heating backup.