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Buderus Products Floor standing condensing boilers GB402


The GB402 is available in the following kW outputs:
  • 320kW
  • 395kW
  • 470kW
  • 545kW
  • 620kW

Features and benefits

  • NOx emissions below 40mg/kWh
  • NOx emissions of 40mg/kWhr
  • Seasonal Efficiency (L2B) 320kW 96.4%, 395kW 96.8%, 470kW 96.7%, 545kW 97.0%, 620kW 96.8%
  • Boiler outputs from 320 - 620kW
  • Suitable for cascading of multiple boilers
  • Controls can be installed at the side or on the front of the boiler
  • Suitable for use with RC35 (single boilers) or 4000 series controls
  • EMS control with auto-diagnosis system
  • Aluminium/Silicon heat exchanger
  • Water-side stream optimised for effective and robust operation
  • No minimum water volume circulation
  • Simple commissioning and maintenance
  • Fully modulating pre-mix burner
  • Sealed combustion operation possible
  • Efficiency of 109.7% at 40/30°C
  • Maximum operating pressure of 6 bar
  • Extremely quiet, operates at 55dB(A) at full load
  • Weight (depending upon output) 410kg to 520kg
  • Easy transport, assembly and installation
  • Can be installed in either orientation to suit the plant room layout.

High performance commercial heating

A high efficiency condensing boiler, perfect for single or multiple boiler installations in medium to large buildings including schools, hotels, care homes, offices and commercial buildings.

Compact, quiet and perfect for both new build and renovation projects.

It combines high efficiency and low emissions with a wide range of practical benefits.

Performance with economy

Available in 5 outputs – 320kW to 620kW – the GB402 has been developed to provide lower running costs and reduced carbon and NOx emissions.

This is achieved through the use of a powerful, lightweight cast aluminium heat exchanger and thermally insulated boiler body.

The clean burning, pre-mix burner and intelligent combustion controller enable the GB402 to operate in a wide modulation range of between 20% to 100%, with a seasonal efficiency of up to 110%.

Boiler and system controls

Technical dataFile typeFile sizeDownload
GB402 Technical data sheetPDF427KB
CAD drawingsDWG33 - 38KB
Floor standing boilers
Wiring schematic diagrams - 4000 seriesJPEG
4121 Control schematics
4122 Control schematics
4323 Control schematics
Wiring schematic diagrams - EM10JPEG
EM10 Control schematics
Wiring schematic diagrams - MCM10JPEG
MCM10 Control schematics
Wiring schematic diagrams - RC35JPEG
RC35 Control schematics

Manual Downloads

Manual  File type   
GB402 Overview brochure PDF Download (PDF 1.4 MB)
GB402 Installation manual PDF Download (PDF 7.3 MB)
GB402 Operating manual PDF Download (PDF 1.2 MB)
GB402 320 ErP fiche PDF Download (PDF 0.1 MB)
GB402 395 ErP fiche PDF Download (PDF 0.1 MB)
The energy-efficiency class indicates the energy-efficiency rating of specific product. Energy-efficiency classes for other products from this line may differ.
Enhanced Capital Allowance Scheme (ECA)