Many thanks, yes I followed your advice and the remote ones now get hot. I guess that means the pump is ok so thanks again for yours and the previous advice, much appreciated.
Thanks for quick response, it is a Jaguar 24KTVJ15 but I do not use the direct water heating circuit as the Central Heating circuit also heats a conventional HW cylinder with Programmer, Zone valves etc.
Additional radiators in an extension prove to be too much for the pump to circulate...
I have an old combi boiler with a weak pump and could easily fit a new pump externally, in addition, not as a replacement.
Can anyone please tell me if this is OK?
(I have already fitted an external expansion vessel successfully when the existing, inaccessible one failed).
Helpful advice will...