combi boiler heating problem, plse help!

[coldrooms]

Hi we have a vokera compact 28 combi boiler, 1 year old. Closed system (?) 8 Rads.

It worked fine last winter but we've had the heating back on & there is no heat whatsoever in 3 of the rads (the last 3 in the system). Have bled every rad, increased the pressure, tried turning off just the ones that work, banged the pipes, pulled up the floor, at first the pipes under the floor that go to the 1st rad that's off were slightly warm, they're now hot but there's still no heat at all in the rads themselves.

Does it sound like a blockage? We could drain the system, would this be the most sensible next step? If so, how do we refill it? Does it refill itself through the valve that you turn on to increase the pressure?

 

[B.O.B DOLE]

get a screwdriver and undow the trv on rads and get some pliers and wiggle the pin in and out and feel the hot water fill the rads

 

[coldrooms]

Just done this, but nothing happened. However, the pipe into the 1st radiator that's not working is now slightly warm.

Have now got the whole lot on full blast & will leave like this all night - if still not sorted tomorrow should I drain the system? See questions about this in my first post. Thanks.

 

[B.O.B DOLE]

Just done this, but nothing happened. However, the pipe into the 1st radiator that's not working is now slightly warm.

Have now got the whole lot on full blast & will leave like this all night - if still not sorted tomorrow should I drain the system? See questions about this in my first post. Thanks.

did you push the pin in and out and shake it all about

 

[coldrooms]

Yes, I could hear movement of water in the pipes but no hot water came through!

Today I have bled loads of water out of the 1st rad that's cold. It heated up right to the top as I let the water out & then went cold again when I refilled the system to get the pressure back up. It still hasn't heated back up despite having the heating on again for over an hour.