radiators not getting hot

mattw

I have a 92 year old colonial with a 1 pipe steam system. I have cast iron radiators. For the last month or so when the boiler runs some of the radiators do not heat at all and others are not completely hot. They are cool enough to touch and some are cold in sections.

This only began recently. If I turn up the thermostat to a higher temperature (72 degrees) the heat will runs longer and most of the radiators will heat up all the way.

What would cause some of the radiators not to get hot. I also have not been hearing the usual opening/closing of the air vents on each radiator.

Thanks

Brad White_24

Your last sentence may have the answer

especially if the cold radiators have the vents which are not apparently working. You say "most" radiators heat up with longer cycles, but not "all" obviously.

Replace or remove and clean out the vents (soak in vinegar for an hour if you can afford to have the heat off) and rinse well.

Or just replace them. See if that does the trick.

Remember the old engineering axiom: In-ee equals out-ee. Air must get out so steam can get in.