draining down a sealed system Help and information on all topics relating to your central heating, air conditioning and ventilation issues.

[davecake]

can anyone tell me the best way to drain down a sealed system?i attached a hose and opened the drain valve water started flowing but came to a stop after a short while. opened a bleed valve on the highest rad and water still came out so still full.

[DEEARR2]

By opening the drain valve the heating system should have depressurised taking the pressure away from the highest radiators. Are the rad valves on the high rads both open? if not the rad will still be holding the original system pressure.