While you wait for answers, we may have found some information which could help you.
Click here for Potterton Boiler Fanpotterton 16/22 pilot lihght out?
My potterton boiler keeps losing water pressure and condens?
E133?
Potterton EP2000 - pump control?
How to replace Potterton EP 3002 with EP 2?
Potterton heatmax combi?