I wonder if anybody can tell me the difference between the pcb part no.21/18867 and the pcb part no. 21/18601 as I had the pcb on my combi 80 replaced by a heating engineer the origonal part was 21/18601 and he replaced it with part no. 21/18867 (this is the part no. On the box the new pcb came in). I have noticed the fan and pump staying on for about 5 mins after DHW demand has stopped they also do this with the CH when demand has stopped. I wondered if it could be to do with this different pcb.
Thanks[/b]
Thanks[/b]