Hot Water Convector Radiator Issue

13bravo

I have one hot water convector on the second floor that is cold (supply and return pipes leading into convector are cold as well). It is in a bedroom with a second convector...which is even further from the boiler but the further convector (which branches off from the supply and return at the very end of the lines) is actually nice and hot. This is a two pipe direct return system built in the 50's. I tried bleeding it but no air or water comes out of the valve. The bleeder valve might be bad but thinking it might be something else since the pipes in and out of the convector are cold. Any thoughts?

Speaking of bleeder valves, second question: I just replaced the gas valve and turned the system on and went to clean and bleed all the radiators. All but the one mentioned above are nice and not. But half of them didn't have any water come out of the bleeder valves (and no hissing air...nothing but silence). Are these just all bad bleeder valves that need to be replaced?

Thanks in advance!!

Jamie Hall

First thing I'd check, and it's easy, is the pressure the system is running at. For a two story house, 15 psi is about right. If it's low,, not only will you not get air out of a bleeder when you open it, you'll be rather lucky is any radiators on the second floor heat at all -- that one that does may just be the fortunate exception.

If the pressure is too low, there should be a way to add a little water to bring the pressure up where it belongs. Then try the bleeders again.

But, as they say, wait -- there's more. You also want to keep a really close eye on the pressure when the system fires up once you do get the air out of the radiators. It should rise, but not more than a few pounds. If it rises more, there's a problem with the expansion tank. It could be waterlogged. It could be precharged to the wrong pressure.

13bravo

Thanks Jamie! I figured the pressure would come up and meant to note it but forgot, sorry about that!

If the gauge is accurate pressure seems good...right at 15 and goes up to about 18/19 when fired up.