The Gloworm utimate is a simple boiler to diagnose, initiall testing should be focused on the basics. i.e This particular boiler comprises of a permanent Live, Neutral, switched Live and earth.
If switched-fused spur is on you should have 240 vac on permanent live. please note this testing should be carried out compentenly with an approved multimeter (Not Neon screwdriver). Once this has been proved turn on heating demand and check for power on switched live, this simple testig proves all external conrols are OK.
Rob, RJS Heating Ltd www.rjsheating.co.uk, August 2009
