since having new thermostatic valves fitted to my radiators the pressure in the system seems to drop for no reason [no leaks to be found].The pump is also very noisy.Could this be a sign that replacement is near.
to fit any trv's the heating system needed to be drained down.
suggest you refill boiler to the recommend pressure then re bled all the rads of air again, then repressurise the boiler again.
