hot water heating system problems

[j j]

we have a hot water boiler/radiators heating system.

I have to keep bleeding the radiators upstairs. is this normal?

where is the air coming in/water going out?

[George Elkins]

Defective or waterlogged expansion tank, perhaps? Are any pressure relief valves leaking or releasing water? The air replaces the lost water when the system cools.

[HeatMan]

No, it is not normal.

With all due respect, I can't see it from here, so I can't tell. You may have a leak somewhere. It may be in the boiler or the piping. Call an experienced hydronic tech to look at it.