Vitocrossal 300 CA3B - Our most powerful gas condensing boiler

With its unique synthesis of proven Viessmann technology and innovative features, the Vitocrossal 300 CA3B takes a bold step forward while retaining the superior Viessmann quality you know and trust.

The boiler combines unparalleled flexibility with maximum efficiency, making it your ideal choice for a new installation or economical retrofit in multi-family, commercial or light industrial applications.

The benefits at a glance

  • Easy-to-remove front door allows for reduced clearances and simplifies installation insmaller spaces.
  • Burners and supply header can be easily removed to facilitate transportation throughsmaller doorways
  • Low emissions and quiet operation from fully-modulating Viessmann pre-mix cylinder burners (up to 3)
  • Total burner modulation turndown ratio of up to 16:1 precisely matches load per boiler
  • The fully assembled boiler simplifies installation and commissioning
  • Flexibility for venting through the sidewall or chimney applications and combustion air options of sealed combustion or room dependent
  • Common venting up to four boilers
  • Easy changeover from NG to LP with a simple turn of a key (Dual Fuel model boilers only)
  • Low inlet gas pressure capability as low as 4" w.c. (NG) for compatibility with a range of supply pressures
  • Large water content extends burner run time and reduces cycling
  • No dedicated boiler pump required due to extremely low water pressure drop through heat exchanger
  • Vitotronic 300 GW6C can be used as a single boiler control or as a cascade primary/secondary control system
  • Seamless integration with building management systems

Exceptional performance and reliability

The titanium infused stainless steel Inox-Lamellar heat exchanger surface provides maximum heat extraction while maintaining a compact size. Its smooth, corrosion-resistant surfaces allow condensate to simply run off – a "self-cleaning" process that ensures continuous condensing efficiency, reduced maintenance costs and longevity.

Combined with our fully-modulating pre-mix cylinder burners, the Vitocrossal 300 CA3B achieves outstanding thermal efficiencies over 96% and delivers exceptional performance and reliability at an attractive price.

Where can I buy a Vitocrossal 300?

To get a quote for a new Vitocrossal 300 CA3 boiler system, please contact a Viessmann Sales Representative in your area via our Sales Network.

For design questions and further technical information, please contact the Viessmann commercial project team at our headquarters in Warwick, RI:

Viessmann Manufacturing Company (US) Inc.
45 Access RoadWarwick, RI

Tel.    401-732-0667  (Toll-free)
Tel.    800-288-0667  (Toll-free)
Fax    401-732-0590

Product details


Rated input
2500 to 6000 MBH - 733 to 1758 kW
Thermal efficiency
Natural gas (NG) or liquid propane gas (LPG)
Application range
For apartment buildings, commercial applications and district heating, new buildings and retrofits.
DHW heating
Additional DHW tank(s) required, for a high level of DHW convenience
Limited 10 year commercial warranty
Additional features
Multi-boiler installations possible with input of up to 16,000 MBH (4,688 kW). For larger systems, Viessmann offers custom boiler controls for virtually unlimited capacities and additional options.
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A perfect match – System technology

"The whole is greater than the sum of its parts." According to this philosophy, Viessmann does not just make individual heating equipment components that meet the high Viessmann standards for quality, reliability and effectiveness. Rather, all products are part of a matching concept, where all components complement one another. Only the perfect interaction of system integrated components draws out the maximum potential of our innovative leading technology.

Viessmann system technology includes everything you need for a reliable and economical heating system. The Vitotronic control unit with remote control, the powerful Vitocell DHW tanks for best DHW convenience, to high-quality solar thermal systems for cost-saving heating.

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