Hi all, I have recently been looking to Renew my boiler. I have a Potterton Suprima 40 getting on in years and fancy having a little more space in our wee house, so have decided to have a combi boiler installed in the garage, and have the hot water tank removed from the airing cupboard along with the tanks in the loft. After having a quote from a recommended local firm I was advised that my 2001 gas supply to my boiler would need to be upgraded to a larger bore, is this common, and would there be anything against changing from a traditional condensing system to a combi one. We have been recommended to go for a Worcester Bosch Green star for our 3 bedroom. Thanks for reading this. All comments welcome on this issue as it is stressing us out a little.