the easies way to find out which component on the system is blowing the fuse is to disconnect them one at a time keeping the exposed wires safe and turning the power back on. if the fuse still blows its not that component, re-wire and try the next one it is a simple process of elimination.on systems with a water cylinder or on the potterton puma range of boilers i would always try the pump first as this is one of the most common things to pop fuses.
jock, April 2009
