guys I am just interested in what would be your plan of attack on this one . Large house, the home owner inherited this problem so we dont know if its been like this from day one . I am incredibly busy and dont even want to do it .. 18 ish rads , 35 kw vokera bag of shi* system boiler . 3 rads furthest away form boiler dont heat up . No stuck trv pins , open l/s , shutting other rads of doesnt seem to make any difference . I put a new pump in a fortnight ago , no difference. As said just interested in where you would start. Go for it lol Thanks in advance .