I have recently installed some new rads downstairs and changed one upstairs.
Instead of using microbore as the previous person had I installed 15mm. The
one upstairs worked brilliantly and still does. The two downstairs don't
seem to be flowing. I have made sure that all the valves are open but still
no joy. They are all bled. I have this evening closed all the upstairs
valves and now no water is flowing through the system any of the rad pipes,
I have traced it all the way back to the cylinder!!
I really don't know whats the matter, I am thinking maybe the pump as it was
allowed to run dry for a couple of hours by accident one evening!!! Only
think is i can hear the water flowing so I am not so sure it is the pump!!!