The Purewell VariHeat is a cast iron condensing boiler that combines traditional durable build quality with modern ultra-efficient condensing boiler technology. The range consists of 5 models with outputs from 70 kW to 180 kW. The highly reliable cast iron heat exchanger is backed by Hamworthy’s 10-year cast iron warranty for additional peace of mind. The fully Energy-related Products Directive (ErP) compliant cast iron boiler is the only one of its kind in the UK. It achieves exceptional gross seasonal efficiency up to 96% with ultra-low emissions (European Class 5), while easily exceeding minimum seasonal efficiency requirements for new and existing buildings.

Installation Options

Installable as single or multiple boilers in modular arrangement, they are ideal to replace atmospheric boilers in existing heating systems. Thanks to modern controls and clip-in modules, the boilers can be integrated in building control systems. Additionally, the boiler can be installed with an optional cascade controller with reliable bus communications for boiler sequencing for up to 16 boilers.

• Reliable and robust cast iron heat exchanger with 10-year warranty (primary & secondary heat exchanger only, T&Cs apply)
• Exceptionally efficient condensing technology with up to 108% net efficiency
• Fully modulating boiler for close control and accurate load matching
• Only ErP compliant cast iron commercial condensing boiler in the UK
• Ultra-low NOx performance
• Tolerant of older heating systems, replaces atmospheric boilers easily
• Reduced cost of refurbishment
• Comprehensive controls including optional boiler sequencing
• Full factory assembled for easier installation but for plant rooms with difficult access it can be supplied unassembled
• Pipe kits available to simplify design and installation
• Parametric 3D BIM (Building Information Modelling) models for all Purewell VariHeat boilers are available from Hamworthy’s website: 
  http://hamworthy-heating.com/building-information-modelling

Pipe kits

To simplify design and procurement, Hamworthy provide a range of pipe kits for 2, 3 or 4 multiple boilers, which are factory tested and part assembled for ease of installation. The kits include:

• Isolating ball valves for water flow, return and gas inlet connection on each boiler
• Flow and return headers
• Pre-assembled flow and return pipe sub-assemblies between boilers and headers.
• Flow line safety relief valve and ½" connection for pressure gauge
• Return line drain valve and ½" connection for expansion vessel in line with BS6644
• Blanking flanges for header ends
• Support legs