For anyone with either Hot Water or Heating problems/odd behaviour with their Modena 102 (and perhaps other Models) it seems from what I have read that the Flow Temp Sensors (Heating and DHW) which are both identical are often the culprit, and replacing them on my Sons Boiler cured his problems.
I found it a fairly easy job, and I did it by first switching off the electric supply, I then turned off all the valves under the Boiler thus isolating it from the system,and to drain it down I loosened the union under the pump, a rag wrapped round the fitting directed the water into a bowl and it was not long before the boiler was empty, I then undid and propped up out of the way the front control panel which enabled me to get a good view and easy access to the Sensors, I used a 15mm Deep Socket to undo and remove them, its probably possible to get at them with spanners but a socket or box spanner makes it very easy and in my opinion is worth getting. Refitting was straightforward, and the sensors only need nipping up as they come complete with fitted O rings, The cost of a Pair of Sensors was £20 inc VAT, so all in all not too bad at all.
Steve.
Steve, December 2006