Thanks all, makes sense that they are in parallel.
The 3rd rad is the last to get hot so I will balance the system as you describe. I'm pretty confident the system is clean and the reason the 3rd rad is last to heat is it's, I suspect, furthest in the system....being in the extension...
Morning all, I'm new here so hello and HNY!
Moved into a new (1930's) house before Christmas. The rear extension is cold compared to the rest of the house.
In the extension there are 2 plinth rads and 1 standard rad, all fed from a single flow and return loop. Issue is they are connected in...