Bleeding a tall tubular Radiator

[Network plumber]

HI,

I have just installed the first of a number of tall (6ft) modern
tubular (20 Tubes wide) radiators. Is there a special technique for
installing and bleeding them, as initially only the three out side
columns on the bleed valve end got hot. After lots of playing, turning
all the other radiators off etc, and bleeding from the over end of the
rad at the top by loosening the blanking nut, I now have the two out
side columns warm. But this still leaves me with 15 cold columns. The
horizontal tube across the bottom is hot.

Thoughts please

Simon

 

[musky1]

Probably like alot more people,who think they can just add rads,different sizes,bigger outputs,different heights,doubles etc without considering whether the boiler input/output can cope.

 

[HOTDOG ø]

is the flow connected correctly to the dip tube side?

 

[Mountain Man]

I had trouble with one of these tall designer rads till I rang the company who asked if I'd seen the tiny label on the back saying TOP. I went all red I did!