potterton combi 80 pcb


17 Dec 2007
Reaction score
United Kingdom
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.
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Hi yes he has fitted the permanent pilot version pcb and you have the electronic ignition version ! It will all work fine except your fan will run constantly at low speed as this is needed to disperse the fumes and heat from the pilot version! If it's the old type pcb beige in colour and not green then cutting link 1 will make it exactly the same as the electronic version and fan won't run! :rolleyes:
Thanks for the speedy reply I thought it may have something to do with the different PCB but the fan doesnt seem to be running constantly, just for about 5 minutes after demand has stopped then it stops.
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I am not sure what cutting that link does but it makes it work!

Its got quite a few other components on one of the versions compared with the other but no one that I know has found out what they are there for!


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