I was servicing my kids bikes a few weeks out in the back garden, near the unit, and when the fans came on to heat the water in the house, the cool breeze from the fans was very welcome in the heat of the sun. Wouldn't mind a bit of sun now though :-/
But to answer your question, I think they are only to heat the system, not cool it down. We don't have the heating on per se (the thermostats are set to 5C) so at the moment it's only used for hot water. From my reading (of the very sparse information with the unit), is that it's a gradual increase in heat, over a number of days. Firstly, the heating system needs to be on for a number of weeks to get it to required temperature (underfloor heating) and then it's just little changes over time from the base temperature you want. Unlike gas / oil where the heat is within minutes so to speak, think this is days. I assume with the A rating, the heat stays in the house longer so gradual changes is all that is needed - time will tell!The radiators upstairs do not get hot, just warm, when heating system is on.
I think I'll need to read up on it a lot more !
Are you friendly with that neighbour of yours? You could ask in "general terms" what the system is like etc...