Can a Heating Manifold Controller drive a Circulation Pump?

If the manifolds controller has triac outputs (silent switching) then you cannot use the output to drive a pump as they are designed for low current restive loads, not the inductive load of a pump. This is normally the case with KNX manifold controllers.

If however the output is a relay with a suitable rating then there should be no issues. 

However, most KNX manufactures offer an object on the bus for controlling a pump. This can be linked to a separate KNX relay with the correct rating for the pump.