I am installing a GB162 boiler what size flue do I need to use?

There are two flue sizes available for the GB162 suitability will depend on the output of the boiler.

The 80/125 flue system is only suitable for use with the 50kW and 65kW version of the GB162, whereas the 100/150 flue system is the standard flue for the 80kW and 100kW versions.  The 100/150 flue system can be used on the 50kW and 65kW for longer flue runs.