I just replaced my hot water baseboard.I have a gas boiler that is brand new.. only about 6 months old(everything worked fine before I did this replacement)I shut the boiler off, then shut the supply off at the boiler.I did the replacement of the baseboard.. everything went good.I turned on the boiler and bled it down in the basement right there at the boiler.The section I replaced was down in a finished basement about 20 feet from the boiler. I went upstairs to the 2nd floor and found 1 bleeder valve. I bled the valve for 3 a good 3minutes.Then I:confused: went to the first floor and found one bleeder valve and bled that one.. o.k... now after about a week and bleeding the 2nd floor and the first floor about 3 separate times the first floor is nice and toasty but the 2nd floor is cold.when I bleed the 2nd floor it starts with cold water,then after about 2-3 minutes it gets hot.. like the hot water is trying to make its way up.. but the baseboard never gets hot... like I said the furnace is new and was installed by professionals... My buddy said about the boiler pressure. There is no gauge at all... just a pressure builder valve that says 12-15 psi.. like it maintains the pressure all the time with this valve... I am stuck.. I tried to bleed it again tonight but had no luck.. I can only find 1 bleeder on the first floor and 1 on the 2nd floor.. any info would be gratly appreciated!! /Thank you

((then shut the supply off at the boiler`))

Did you turn the water back on?
All boilers need a gauge. Install one.

((There is no gauge at all... just a pressure builder valve that says 12-15 psi.. like it maintains the pressure all the time with this valve))

Pressure fill valves as you call them cannot be depended upon to be accurate.

Install a gauge.
You need to know the altitude of the water level in your home and that is done by pressure/altitude gauge. It will also have a temp gauge built in so you know how hat the boiler is running. I a professional installed the boiler he should be shot for not putting in a gauge.