joining onto microbore

[del15]

i have a conservatory and have added radiator from one in next room. System runs on 8mm micro bore but now neither rad is getting hot. Flow pipe on existing rad hot but cold through both rads. System runs off vaillant combi. Pressure at 1 bar

 

[chrishutt]

8mm tube is probably too small for the load your putting on it and the length of run. The shared pipe should be 15mm, although you might get away with 10mm if the run is short.

 

[JPC]

did u solder it ? is it now full of solder on the inside of the pipe ?

try turning down some other rads and see if its blockage or indeed u have asked too much from a 8mm pipework