Hi everyone... I am considering replacing my 25 year old Glow-worm open vent heat only boiler which is currently supplied by 15mm (1/2inch).
I am interested in the Vaillant Ecotec plus 428 and one installer is saying that I need a 22mm supply up to 1metre from the boiler and then a 15mm connection. I always understood the gas pressure was the main issue and I can understand 22mm would give greater pressure.
I can't find on any site any recommendations for this and I am reluctant to proceed as major re-piping would mean major disruption to the house.
The boiler is the only gas appliance in the house.
Your advice would be greatly appreciated lads !