combi boiler falling pressure

[clc]

I have a combi boiler that keeps on loosing pressure once the heating has gone off. the radiators are not heating up properly so I think I may have air in them, do I bleed them with the heating on and do I have to ensure that the pressure is up all the time and do I start with the furthest away radiator.

Cheers

 

[glasgowgas]

switch combi OFF

pressurise to 1.5 bar

vent rads 1 at a time, starting from downstairs

after each vent of rad, go back and re pressurise to 1.5 bar

after all rads are vented, check pressure is 1.5 bar

vent boiler pump

make sure auto air vent on boiler is open

turn on combi, run central heating, observe if any pressure rise

 

[bengasman]

Do the rads get hot at the bottom?

 

[clc]

Do the rads get hot at the bottom?

some are hotter at the top whilst others are the same temp top and bottom

thanks for the reply by the way.

 

[bengasman]

Could be dying pump, corrosion, or poor balancing.

 

[clc]

Could be dying pump, corrosion, or poor balancing.

Thanks, I have just bled all the radiators and increased the pressure, will wait and see if it falls again, if it does will get some professional help in.

thanks again