08/01/2019
  • Product launch
The Purewell Variheat mk2 benefits from a cast iron heat exchanger and upgraded controls.

Hamworthy has launched the upgraded version of its customers’ favourite product for refurbishments, the ErP-compliant Purewell Variheat cast iron condensing boiler.


The Purewell Variheat mk2 builds its success on the cast iron heat exchanger which is especially tolerant of older heating systems and hasn’t changed in design since the previous models dating back to the 70s. A 6 bar pressure rating makes the boiler suitable for high rise buildings.

To bring it in line with Hamworthy’s remaining range, the upgraded boiler features the advanced Siemens LMS controls platform – already used in all condensing, pre mix Hamworthy boilers. It allows easy cascade options controlling multiple commercial boilers and hot water at the same time , providing energy-saving benefits and allowing flexible boiler control regimes  for an extended product lifespan. The new version is now also equipped with full spark ignition, updated from the previous hot surface ignitor.
As the only cast iron boiler of its kind in the UK, the secondary heat exchanger with copper tube and aluminium fins allows the boiler to condense. This means it is not only highly efficient but also compliant with all Building Regulations and the Energy-related Products Directive (ErP). Plus, thanks to low NOx performance (<40mg/kWh, European Class 6), the Purewell Variheat mk2 also scores well on assessments for future-proof commercial heating system design and building performance.

Andrew Dabin, product manager for Hamworthy Heating, commented:

“The new Purewell Variheat mk2 is a product evolution focussing on longevity, ease of service, control and efficiency. While we looked at impending legislation to not only comply but exceed requirements, reducing especially NOx emissions, we drew on customer experience to improve access for maintenance and handling. Thanks to their feedback, the now full spark ignitor is easier to service without the need to remove the complete burner.

With additional transport casting lugs at the front of the sump to match the existing rear ones, we’ve made sure movement with a pallet truck is as safe as it can be, whilst preventing damage to the appliance. The controls platform update does not only allow closer control of multiple boilers for improved efficiency but also gives Hamworthy consistency across the condensing boiler ranges for all gas air pre mix appliances.” 

An electrical socket on the front of the new version helps servicing without power outlets in the plant room, along with front cover hooks for quick and easy removal of the cover. A split mains and low voltage wiring harness reduces potential incorrect fault codes.
The boilers are compact which makes them easy to transport to and site in smaller plant rooms. They fit on the footprint of the Purewell Variheat mk1 and use the same pipe kits, service clearances and key combustion spares. The mk2 boilers also have the same pipe centres as older, original Purewell boilers  which aids replacement. 

The Purewell Variheat mk2 comes with a 10-year warranty on the heat exchangers and is available in 5 models from 70 to 180kW of output.

For more information visit the product page.