AFAIR the Xtreme has a really backward pump design whereby a failure could also take out the main boiler pcb...the control electronics has been split from the pump.
Interesting theory....
Because it can't be backed up with real life experience can it? How many Intergas PCBs have been taken out by the pump?
Far more PCB's get taken out on boilers when the pump leaks and water gets into the pump causing a dead short.
So how did you make that leap?