Keston Celsius 25 is a wall mounted gas condensing boiler with fully modulating output of 7kW to 25kW.  Very high efficiency (up to 97%) and can save up to 30% on fuel bill.

The room sealed boiler is compact in size measuring just 621mmHx472mmWx250mmD, so can even be fitted in a standard kitchen cupboard if required.

Small diameter (50mm) standard muPVC kitchen wastepipe is all that is required for the flue and air intake and can be up to 20 metres either horizontally or vertically.  Alternatively the Keston composite flue (70mm diameter) can be 60 metres long.