heating query

[kev1911]

hi all,
got a boiler in an extention with new added rads,fed in 22mm,all is working fine except 2 rads on the old pipework they remain cold and are fed off drop downs,the system has been powerflushed and bled several times but still they remain cold,any advice please as its doing my head in now.
thanks in advance

kev

 

[kevplumb]

close the working ones off and see what happens

 

[kev1911]

close the working ones off and see what happens

hi mate,thanks for replying so quickly
sorry i forgot to say in my post i've already tried that still no different.