Wessex ModuMax mk3 condensing boilers Stacked 3 high
Stainless steel high efficiency, fully modulating condensing pre-mix floor standing boiler. 

Available in 5 modules with outputs (@50/30°C) of 97, 116, 147, 196 and 254kW. Individual boiler modules can be stacked one, two or three high in up to 15 combinations.
  • Fully modulating boiler which benefits from lower fuel usage and closer load matching.

  • Space-saving stacked module design delivering 762 kW in less than a square metre footprint.

  • Flexibility in system design with differential temperature up to 40°C. Lower flow rates associated with wider differential temperature allow smaller diameter pipes and smaller pumps that can lower capital cost and also lower energy consumption.

  • The heat exchanger is manufactured using stainless steel and backed up by with a 10 year heat exchanger warranty, making the Wessex ModuMax mk3 an extremely robust boiler. 

  • Compensate for distribution losses in large commercial heating systems with max 90°C flow temperature.

  • High relative velocity within the waterways helps to reduce the opportunity for sedimentation.

  • Enhanced sequence control options for up to 16 boiler modules

  • Low water content, rapid response, with ultra low standing losses.

  • Low environmental impact - NOx - <40mg/kWh for maximum BREEAM credits.

  • 10 bar maximum working pressure allows installation in basement for high rise buildings.

  • Easy access to plant room as the Wessex ModuMax mk3 fits through a standard doorway and can split into modules for limited access or rooftop plant rooms, as well as packaged plant rooms.

  • Buy in confidence from a UK manufacturer with decades of commercial heating and hot water expertise.

  • Extensive back up and support from our team of experienced engineers across the UK.
Get in touch to find out more about the latest generation of Wessex ModuMax boilers, British engineered for decades.  
  Title Type Size  
Wessex ModuMax mk3 boiler brochure Wessex ModuMax mk3 boiler brochure Product brochures 3455 kB Download
Wessex Modumax mk3 dimensions Wessex Modumax mk3 dimensions Dimensions 1263 kB Download
Wessex Modumax mk3 technical data table Wessex Modumax mk3 technical data table Data tables 102 kB Download
Navistem B3000 instruction manual Navistem B3000 instruction manual Installers guides 2177 kB Download
Wessex ModuMax mk3 Installers Guide Wessex ModuMax mk3 Installers Guide Installers guides 6681 kB Download
Wessex ModuMax mk3 user instructions Wessex ModuMax mk3 user instructions Installers guides 76 kB Download
Wessex ModuMax mk3 scheme 1 open vented with low loss header Wessex ModuMax mk3 scheme 1 open vented with low loss header Hydraulic schematics 78 kB Download
Wessex ModuMax mk3 scheme 2 sealed primary with open vented second and plate heat exchanger Wessex ModuMax mk3 scheme 2 sealed primary with open vented second and plate heat exchanger Hydraulic schematics 71 kB Download
Wessex ModuMax mk3 scheme 3 single pipe, boiler and system pump and LLH Wessex ModuMax mk3 scheme 3 single pipe, boiler and system pump and LLH Hydraulic schematics 78 kB Download
Wessex ModuMax mk3 scheme 4, single pipe with independent DHW Wessex ModuMax mk3 scheme 4, single pipe with independent DHW Hydraulic schematics 86 kB Download
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Wessex ModuMax mk3 wiring diagram Wessex ModuMax mk3 wiring diagram Wiring diagrams 379 kB Download
  • Easy fit replacement for refurbishment projects.

  • New build projects.

  • Roof top and basement plantrooms

  • Housing developments and flats using district heating networks.

  • Energy centres within district heating schemes and larger premises

  • Large commercial and public buildings including schools, hospitals and hotels.

  • Medium sized commercial and public buildings including schools, hospitals, offices and hotels.

  • Small industrial and manufacturing premises.

  • Locations with substantial and continuous heating load including hospitals, care homes and hotels.

  • Hybrid systems alongside combined heat and power (CHP) and/or other renewable technologies such as biomass boilers.
  • Manifold Kits to match the boiler model
  • Flues available through our flue partner Midtherm Engineering
  • Single Boiler Controls
  • Outside air temperature sensor QAC34 (Part no. 533901457)
  • Domestic Hot Water sensor kit (sensor and pocket) (Part no. 563605674)
  • Mixing valve heating circuit control kit (clip in control module, temperature sensor and pocket) for 1 zone (Part no. 563605668)
  • Mixing valve heating circuit control kit (clip in control module, temperature sensor and pocket) for 2 zones (Part no. 563605669)
  • Mixing valve heating circuit control kit (clip in control module, temperature sensor and pocket) for 3 zones – Note: cannot be used in conjunction with volt free contact kit (Part no. 563605670)
  • Programmable room sensor QAA75 (Part no. 533901587)
  • Offset adjustable room sensor QAA55 (Part no. 533901589)

  • Multiple Boiler Controls
  • Outside air temperature sensor QAC34 (Part no. 533901457)
  • Volt free contact kit for remote status signalling AGU2.550A109 (Part no. 563605666)
  • Heating circuit sensor kit (sensor and pocket) QAZ36 (Part no. 563605673)
  • Merley boiler sequence controller, wall mounted (Part no. 563605672)
  • Merley boiler sequence controller, loose kit for panel mounting (Part no. 563605671)
  • LPB Bus communication module OCI345, one required per boiler module (Part no. 563605667)
  • Programmable room sensor QAA75 (Part no. 533901587)

  • Choose from a wide range of service contracts to help maintain optimum performance.
  • Book commissioning at the same time as placing your order for improved warranty terms.