Vailant ecoTEC plus 637 System Boiler
S Plan
Unvented Cylinder
Honeywell ST6400C controller
13 Radiators
Boiler not igniting - S.97 F.75
Boiler was working fine before 2 radiators were relocated during renovation.
Now boiler fails to ignite and gives s.97 then F.75 code.
System has been...
