Head scratching???

Hi guys - A boilermate II question -


We are having circulation flow issues from the boiler to the thermal store - Pumps  recently replaced and  the old ones showed significant signs of magnetite build up when removed.

Boiler firing but modulating down quickly as it appears that we are not getting good flow around the primary circuit - if any!

The hot feed pipe from the boiler at the top of the boilermate is very HOT  - return out of the pump is luke warm / even cold to the touch and pump running & set to number 3.  Has anyone ever experienced any blockages at the top of the boilermate either flow or return to the boiler?

Thanks