I am helping a friend install a Glow-worm 30 cxi gas boiler. He lives in France but bought the boiler in the UK. It is intended to use the system without a hot water cylinder and we have concerns about the possible reduction in flow rate as more hot water taps are turned on. We would like to run 22mm pipe from the hot water outlet on the boiler but as the inlet is only 15mm this may prove fruitless. Does anyone know how we could provide a steady flow rate of hot water with this boiler?