Gas and Oil Home Heating Furnaces - bleeding radiators

I have the old fashioned cast iron radiators. I am in an OLD two story home. I have bled the radiators before with no problem, but this time I get water from the radiators downstairs but not upstairs. It is 20 below outside, the furnace is on but the radiators upsatirs aren't getting completely warm - any ideas?

I suspect you need to add water to the boiler/heating system. You will need to trace the piping into the furnace, to find the water supply line. There should be a shut-off valve just upstream of the pressure regulator, in the water supply line. First, make sure the valve is open, then try tightening down on the bolt on top of the pressure regulator. Listen/feel the pipe for water flow. If you cannot hear water flowing, either the valve is closed, or you probably have a clogged basket on the upstream end of the pressure regulator. IF you cannot get water flow, post back and I'll help you on cleaning the basket/regulator.

If you get water flow, do not be afraid to let it flow for a couple of minutes, the radiators hold a lot of water. Turn your thermostat up high, like 80 degrees (so the pump will be circulating the new water), and try bleeding your radiators again, about every five minutes. You should eventually start to feel heat in the bottom of the radiators, and it will move up the radiator after each venting.

Post back and let us know what's happening.

Good luck,

Rick

Thanks arkayassoc,
After I tried to bleed the lines, I went to my basement to look at the pressure reading - turns out my expansion tank was leaking like a sieve. I got it replaced and now am bleeding the radiators again, this time it is working. I am glad I found this website.
Appreciate the adivce.