your pump is probabily on its way out, so probabily need a new one
mac
December 2009
shut off your valves on your rads upstairs and bleed the ones downstairs remembering that if its a combi you will need to repressurise the system through your filling loop.if its gravity feed it will replenish itself through the slave tank which will be a small tank next to your cold water tank
mark
December 2009
Automatic Answer
We may have found other answers which could help you.
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix home heating systems.