i have a baxi back boiler which i believe is a closed loop system with a bubble in the tank for heating the radiators,we had a new pump installed which all ran fine now the cold weather is here some of the radiators are cold others hot,there is water in the cold rads but no end of bleeding seems to cure it,ive tried draining down the system to get asll the gunk out and have clear water running from the bleed off can any one help please????

gregs409l, January 2012

When you drained the radiators did they all drain, Just in case some isolator somewhere. If yes forget.

From what you say, boiler heats tank, pump moves water from tank to radiators, ending up back in tank. some rads get hot some stay cold. what type of radiator control do you have, Initial thought is that you need to balance the rads. You have on one side of rad, a valve, thermostatic or other. on the other end is a balance valve, sort of allow more or less water through. so. On the ones that are cold, make sure they are fully open, But allways turn back a touch, so they are not hard against the stop. Then look at the others, the ones that are getting hot, close the valve a bit on the hot ones, does that improve things, if so continue with small adjustments, until all ok. You could use a thermometer to check and get all the same. IF does not work, repost with all details, boiler Make Model etc plus what done.

SD, January 2012