How do you fill the underfloor heating system?
The underfloor heating system should be filled with water and fully vented of air. This can best be achieved using mains water pressure through the two end caps. All valves should be closed and the flow end cap connected with a hose to mains water, with the return end cap connected to a hose laid to waste water point. One by one flow and return valves are opened and closed on loop purging them of air.