Interesting how Bill's posts have been removed???
Anyway, from doing abit of research, it seems that PB102 is a common grade in the UK which is equivalent to C510 in North America. C544 is more common over here yet it doesnt seem that there is a comparable British Standard equivalent. See attached link for info…. **LINK** .
I still wonder if both C544 and C510 are ok for boiler use…..i would like to buy C544 which is far more accessible.
Thoughts?