Gas and Oil Home Heating Furnaces - hot water heating problem

I have a very old hot water boiler and radiator heating system. I have noticed this winter that the radiators on the second floor get nice and hot while the ones on the first floor at best get warm. My system dosen't have an automatic water feed so I am forced to turn the water on every so often. I know I have some air in the lines, I usually try and bleed the system every other month after I add water. My system dose have a circulating pump, do you think this might be bad? Thanks for any help!

JDK

Seems as though you may still have air in the downstairs lines. Is the system zoned for 1st and 2nd floors. You'd have two t'stats?

If you had a bad circulating pump, you would not have hot radiators on the second floor.

Usually air in the system migrates to the point of highest elevation, and/or the furthest point from the circulating pump.

I agree with fjrachel, it sounds like a zone problem. If you have two zones, you will notice two return lines Tee'd into the circulation pump, and there will be two motorized valves (one for each zone) in the boiler discharge piping.

install a water regulating valve and set it at 15 psi.It will automatically feed your boiler when needed.PDF