While you wait for answers, we may have found some information which could help you.
Success
Message
my isar he24 keeps flashing h3what does this mean?
isar he24 heating on permantly?
fault code meaning?
re-filling?
Can you help with a part number or name?
Isar HE 35 heats central instead of warm water?
Isar Boiler?
should i get my boiler fixed or replaced?
Fault codes LF and H2 on my isar He30?
yet another problem ideal isar he30?
l and f flasing on isar he24 boiler?
How to fix a leak between the burner and heat exchanger?