whats a more powerful pump then a grundfos ups 25-50 130

[Sachis]

Hi i have a grundfos pump 25-50 130 p/n 59525418
radiators downstairs are cold and upstairs hot after an 1-hr 2 hrs then the downstairs gets hot
i think the pump i have is too weak
would would be a more powerful pump to help with this ?
thanks

 

[ShaunCorbs]

How old is the pump as it sounds like it’s failed not too small just weak

 

[fowlerboi]

Why have you deduced it must be the pump?