This description shows how to verify and balance a Uponor (Wirsbo) CoSy Radio underfloor heating system, with WGF and Pro 1 Manifolds. It can be used for other underfloor heating system as well, since the function is similar for all underfloor heating systems.

A underfloor heating system in its simplest form contains of two manifolds where the heating loops are connected and a circulation pump. However, most systems are automatically operated, with room thermostats which sends signals to a control unit (master unit), which opens and closes the actuators on the manifold and the rooms get the right temperature via the heating loops in the floor.

With a non-balanced system and at low outdoor temperatures are the thermostats often capable of self balancing the system, because all thermostats will not call for large amount of warm water simultaneously. On the other hand, when the outdoor temperature is very low, the thermostats will open up completely and it will reduce water flow to the longest heating loop and the result is cooler floor.

After reading this description, you will have a good knowledge of how an underfloor heating system works and how common errors can be corrected.

The house in this description is a single storey house built 10 years ago with concrete slab and underfloor heating. One large and one smaller room farthest from the manifold cabinet never had warm floors in winter. Heating loops position and length has never been marked on any house plan. Nor thermostats relation to channels and actuators. Many plumbers have previously been in the house and changed the settings, so existing notes from them could not be trusted. We had to start over from zero and begin locating the heating loops.


At the control measurement, we found 10 heating loops in eight rooms, with temperatures 18-24 degrees Celsius.


The rooms had following temperatures after the adjustment.