john2 wrote:
Owain wrote:
Coldtoes wrote:

Our boilerman came round and checked the pump, which he said was
working. He diagnosed a blockage possibly caused by a build up of silt
and sludge in the system. Following his directions we used chemicals
(Sentinel) to clean the system out. ... On our second visit from
our boilerman he recommended a powerflush - but suggested one last go
with a different brand of chemical (Fernox). ,,,


If one radiator and the tank is hot the boiler and pump are probably OK,
the rest are blocked. Could the system be half full of air after
draining and refilling. Bleed the radiators properly and try opening up
any balancing valves or thermostatic valves on the radiators.

john2

On mine the pump itself was blocxked with bit of rust and the sludge
made it turn too slow. I had to clean it frequently until the system
was clean.