Cold Radiators in different rooms at different times

Rob_38

My system is a 1-pipe steam. I have a 2-story house with moving heat from any radiator on any given time. I am having 6 out of 10 units to heat every cycle,but not the same 6! My pressure is 1.75 psi or so. I have replaced several air vents, but sometimes even they want heat and the old vents will. I have thought about changing or installing a larger, higher volume vent at the end of the main line. I have not found 1 at this point. What do you think?????? Rob

nicholas bonham-carter

mysterious venting problem

you definitely need to vent the main lines,preferably at the end of the dry return as they come back to the boiler.

air remaining in these main lines can cause all sorts of uneven heat problems.

i would advise you to get a copy of dan's steam book from this site.it will explain in greater detail the location of vents.

that being said, the vents are usually close to the elbow on the dry return, where it drops down to the floor by the boiler.look up by your basement ceiling, and follow the pipe looking for any pipe plugs which may now close off the old tappings.

if you have more than 1 main steam return each one should be separately vented. vents for these locations have more capacity than radiator vents, and should NOT be mounted right on a "tee" but back about 15 in. to protect them from water-hammer.

try and get your pressure down to ounces rather than psi.--nbc