wehave a potterton profile 50e which keeps cutting out?

Reading between your lines my guess is that whoever did your "service" last year may have taken advantage of you.

If the fan and pump were both broken then I'm wrong but my suspicion is that they were changed unnecessarily to crank up the bill. Was it a fault-call or just a service visit?

If it was just a service visit you might do well to seriously consider changing your supplier otherwise "they" may replace the thermostat and insist that the circuit board and maybe some other things are playing up too.

Peccavi
December 2008