vapor system missing Hoffman Loop?

vapor system

i see what looks to be a hartford loop, by your boiler, and it looks like a vapor system to me.

can you read the mfg's name from radiator valves, or other bits and pieces in the basement?

a picture showing more clearly how the steam supply pipes come out of the top of the boiler would be helpful.

i see that the pressure is regulated by a pressuretrol, instead of a vaporstat, which may account for some of your problems.

do you have a copy of "the lost art of steam heating" available from the shop? it will explain many things about steam which will help you get this system working as it once did-quiet, economical, comfortable.--nbc

That's an "O-E" water seal in your first pic

with the diamond emblem on it, so this was originally an O-E Vapor system. It's covered in Lost Art, Chapter 15, page 264.



What you probably have there is a pair of steam main vents and a pair of dry return vents. When you take the vents off the steam mains, you get steam, but there is no steam in the dry returns- just air and water.



On a radiator with a water seal, the vent hole is probably plugged so air can't leave the radiator. This would keep it from heating. I think the vent hole is in the screw next to the check ball.



On a radiator with a thermostatic trap like the other one you posted, the trap element has probably failed. You can get replacement elements for almost any trap.