Hampshire educational building achieves efficiency gains with Modumax mk3

An educational building in Hampshire, committed to sustainability and operational efficiency, recently upgraded its heating system by replacing an aging steel shell boiler with modern, highly efficient Modumax mk3 condensing boilers. The project aimed to enhance performance, reduce carbon emissions, and lower fuel consumption. 

The existing heating system had been in service for nearly 30 years and operated at an estimated 80% efficiency. Its fixed output design caused poor responsiveness, frequent cycling, excessive fuel use, and rising maintenance costs. With the building requiring continuous heating and seasonal demand fluctuating, a more adaptive and energy efficient solution was essential. The system also needed to integrate seamlessly with the site’s Building Management System. 

ARB Mechanical Engineering, in collaboration with Salvis Group Ltd and Hamworthy’s Area Manager, installed three Modumax mk3 floor-standing condensing boilers. Each boiler consists of three vertically stacked 762kW modules, delivering a total of 2286kW across nine modules. Thanks to their modular and compact design, the boilers fit within the existing plantroom footprint while providing the high output needed, improved modulation, and enhanced overall efficiency. 

Matthew Kirkpatrick of Salvis Group Ltd explained,  

Given that the building requires constant heating throughout the year, the existing boilers had to remain operational during installation. As the new boilers fit within the existing footprint, only a brief shutdown was required to replace the isolation valves

he building also retains nine older Hamworthy Wessex mk2 boilers installed ten years ago, which continue to operate reliably as secondary support units. The original steel shell boiler is now held in reserve as a backup while plans for its future replacement are under review. 

One of the key advantages of the Modumax mk3 system is its high output-to-footprint ratio, made possible by its stackable, modular design. This allows the system to deliver the required heating capacity in a smaller space while improving modulation and turndown for better efficiency. Flow and return headers supplied by Hamworthy Heating ensure effective hydraulic separation and optimal water distribution. 

The Modumax mk3 system achieves a seasonal efficiency of up to 95%, significantly reducing energy consumption and carbon emissions. Its 45:1 turndown ratio across the nine modules also enables the system to match real time heating demand closely, which is crucial for buildings operating continuously. This feature reduces cycling, enhances efficiency, and allows individual boiler modules to be taken offline for servicing without affecting overall system performance. 

Matthew Kirkpatrick added,  

We chose the Modumax for its excellent turndown ratio and high heat output relative to its footprint, which is essential in space constrained plant rooms. We would recommend it for similar projects.

Following its upgrade, the educational building now enjoys a reliable, flexible, and future ready heating solution. Energy use and carbon emissions are reduced, consistent performance is ensured, and maintenance is simpler, aligning perfectly with the customer’s long term sustainability goals. 

Read the full case study, here.