Our central heating any time we have to do anything with it we always have lots of problems bleeding it, I expect this is due to it being fitted in an old house and most of the runs are micro bore 8mm. I can get the water up to the boiler ok but it is from the boiler to the pump and rads we get the air locks. I am just about to fit a new hot water cyl in a different location and was wondering at that point does the heating pump need to be after the boiler or can it be fitted before to push the water through the boiler and round the rest of the system.

Cheers

pump should always pump through boiler and not pull it through and pump needs to be fitted after your fill and vent otherwise it will pump over