manufacturers can only give their opinion/advice based on what and how you describe the problem!
for the sake of 5 mins. i would remove the venturi from the fan and see if it is clear, then i would drain the boiler of both system and hot water in order to remove the plate heat exchanger - this convects the heat from the primary circuit to the domestic draw off - see if the bottom holes on the left and right are clear. if they are not, then i would flush the system, and replace the primary thermistor which is located at the back on the right hand side of the main heat exchanger. last of all check your hot water flow rate!
Big A, February 2009
