Ive got a problem in an old Victorian house with some rads not heating up. Im not sure on the model of the boiler but might be able to find out. There are 10 big rads in the house and most have the pipes running from ceiling to floor and back again, with very high ceilings. The upstairs was turned off for a few years but we opened up all the valves and the upstairs gets hot but a couple of the downstairs rads stay cold. We have tried turning the upstairs was down to nearly off but 3 downstairs still stay cold. We emptied the system, vented with copper storage tank, and the 3 rads downstairs got hot while the drain tap was open so water can flow through them. When we refilled the system and bled it water came out every air valve but the 3 rads stayed cold. Does this seem like the pump might not be big enough to cope with 10 rads? The water from the taps is absolutely scalding, will have to check the stat on the tank in case its set to high but it was hot very quickly even with the system being off for quite a while.