I currently have a baxi bermuda 551 back boiler central heating / hot
water system. It has a gas fire on the front
which is no longer used.

When I turned on the central heating - it's been off since last winter
- the there was no characteristic gush of water surging round the
system and the radiators don't work, apart from one in the back bedroom.

I bled the radiators, checked the valves on the thermostatic radiator
controls weren't stuck, but still no joy.

After looking at the boiler and reading some previous posts, I am coming
round to the idea that the pump is not working. The boiler still heats
water for the hot water system but it isn't coming on and staying on for
any period of time as it usually did when the central heating was on. I
can't quite work out why the back bedroom radiator is working ok, unless
water is reaching it via the ho****er system.

* How easy / expensive is it likely to be to replace the pump on this
'antique' boiler (getting someone qualified to do it that is)

* If I replace the back boiler, could I use a combi boiler but basically
keep the same hot water/ central heating setup. The back boiler
currenly heats water in a hot water tank in the airing cupboard.

* Are there any reasons other than aesthetic why I can't put a combi
boiler on the fire place using the chimney as a flue. i.e need to be
certain height above ground, thereby minimising changes in the plumbing
which is all currently situated there.

* If I went for a condensing boiler, other than finding a way to run off
the condensate, could this be situated on the fire place as above.

many thanks
angus