Plumbing Questions? Ask a Plumber for Answers ASAP
Good morning, and welcome to the Technical section in JustAnswer. My name is ***** ***** I will help you today. There's no time pressure on this topic - it will stay open for many days, and you can reply at any time. I will be away from my desk sometimes, but will respond as soon as I can.Since you have a combi you probably have a sealed system. If so, you need to repressurise the system after venting. Can you see a filling loop that looks like this?
If the pressure is in the correct range (I would not set it above 1.5 bar at cold), and you open the radiator vent, then air should come out followed by water. If not then there is a blockage somewhere.If you shut both radiator valves and remove the radiator, and place towels and a shallow tray under a valve, you can open that valve and check that water flows. It will probably be a bit squirty, so keep more old towels around just in case. Repeat for the other valve. If both are clear then the radiator vent must be blocked.
Excellent! You did well :-)