ideal isar he 24
dhw open tap to draw hot water the boiler fires up and pump is running fine, it can take 20 to 30 seconds for the warm water to reach the tap, the distance from the boiler to the tap 3 mtrs
the diverter valve head appears to open ok but still cold for a long time

Telec Ltd, March 2009

there are many things that this could be so it's difficult to say. try and run the hot water when the heating is cold, feel the heating flow pipe directly beneath the boiler and make sure it stays cold. none of the hot water should be passing down this pipe with the tap on. also check the gas rate on dhw demand, it should be 24kw net (hence isar 24HE) it could also be a blocked calorifier due to sludge. hope this helps!

andy gas man, March 2009