We have radiators on three floors. For some time it has taken a while for the upper floor rads to get hot but the first floor is always ok. New Valiant condensing boiler fitted some 18 months ago when radiators drained down. No problems with ground floor rads until yesterday. All rads checked for air and bled. Pump appears to be working as it vibrates to the touch but I tapped it with a hammer yesterday just in case the impeller was stuck and this got the rads going. No heat in the downstairs rads again this morning but all others ok. Suspect pump needs replacing as it is over 20 years old from memory. Any suggestions welcomed
