Underfloor heating manifold setup and loop balancing

Cold corners in a heated floor are almost never a boiler problem. In nine cases out of ten the loops were laid at very different lengths, the manifold was never balanced, and the short circuit nearest the pump swallows most of the water while a thirty-metre loop under the far bedroom gets a trickle. So I start by measuring what you actually have: how many circuits enter the cabinet, what area and what covering sits above each of them, how the mixing group is set today, and what the supply temperature really is rather than what the dial claims.

The cabinet itself has to be reachable. I place it where the loop ends converge, mount it level, leave depth for the mixing group, the pump and the actuators, and make sure the door opens freely. A manifold walled in behind a tiled niche is a service call you end up paying for twice. Each circuit then gets its flow set on its own flow meter according to its calculated length and load, not by eye, and the whole set is rechecked once the floor is warm: a system balanced cold always drifts as the loops begin to give off heat.

Air is the other half of the job. Every loop is flushed separately with the rest closed off, automatic vents and manual bleeds are tested, the fill pressure is set and the expansion vessel checked. Supply temperature is matched to the covering above, because tile, engineered wood and laminate do not tolerate the same flow, and the thermostatic or weather-compensated group is adjusted to that figure.

What is included:
— survey of existing circuits, their lengths, areas and floor coverings;
— cabinet placement, mounting and full manifold assembly;
— flushing, filling and loop-by-loop air removal;
— flow setting on every circuit with a written balancing table;
— mixing unit and supply temperature tuning under your covering;
— actuators wired to room thermostats zone by zone and tested;
— pressure test before the screed with a signed report;
— first heating programme after the pour, step by step.