This was a repair I did this week in Barnsley on a Vaillant ecotec plus 837. The boiler was losing pressure and working intermittently displaying the F.75 fault code. I was able to repair this boiler with one visit. If you are looking for a bit more information regarding this fault then check out my Vaillant ecotec F75 fault code page.
Vaillant Boiler Repair Service
Expert Gas Safe Registered Vaillant Boiler Service and Repair Specialist