I'm going to have my combi boiler replaced, but fitters who have looked say current 15mm pipes on CH flow and return are too small. One suggested replacing about 1m up and 1m down [from the boiler] with 22mm to help heat travel away from boiler. Do you think this would make a difference? Does it depend on the boiler fitted? It would be either Vaillant Ecotec plus 831, Worcester 30si or Alpha 28K.
Thanks .
Thanks .