Another first fix question from me. You can tell I'm starting to triple check before boards start flying up!   Ref UFH manifolds: Only one zone but as we're split level we have two manifolds. Upper one is in the plant room so no drama's there. Lower one is in the under-stairs cupboard.   So far to the under-stairs manifold location I've run:   22mm feed and return 1.5mm 4 core for the pump power and control 1mm 2 core for the actuators   Is