How can i fix my glow worm compact electronic combi boiler?

I would suggest that the water flow switch is stuck in the "on" position, this is easily recitified by cleaning the switch or replacement of it... In some very rare cases, older "mixing" showers can also cause these appliances on get stuck "on" when the mixing shower's thermostat cartridge fails and gives the effect of water passing through the appliance.

ccMods
July 2006