baseboard heating

flooby

i have baseboard oil hot water heat in my home the loop system one ins feed up center of house 3/4 ins return in baseboards around outside walls circulator seems to work ok its a taco007 with zone valves .down stairs is ok .too hot if anything. but up stairs never seems to get very hot bled the system no air in it just replaced the feed valve it was bad and i did not know it. a 12 to 15 pound pressure valve. can anyone give me any ideas of what i could do. could circulator be too small. or loop to long thanks for any help you can give me thanks finbar looby