Pressure in 14 story steam system

MWSASSO

I live in a 14 story building with a circa 1929, 2 pipe steam heat system with a 1970's or 80's replacement boiler. Condensate used to run through the pad of the building but the pipes went bad in the 50's and the condensate returns were moved to the ceiling of the 1st floor. No longer any radiators on the 1st floor. Our system is lumpy and we have spent the last few years adjusting the slope (no longer possible to run downhill etc) and adding vents  etc etc. We seem to be in pretty good shape now, much less noise, banging etc. The current pressure is set at 2psi and we get plenty of heat to the 14th floor. Would it be a good idea to lower the pressure to 1.5 or 1 psi? Would that be likely to help with noise?

Also the original plans for the steam system had vents and we have reinstalled them which made a big difference. We use steam vents on each main steam line and air vents on each main condensate return line. the steam vents got the steam to move and the condensate air vents seem to have helped dramatically with noisiness. Do you have any input on types of vents to use?

We do not use a vacuum or condensate return pump.

In the literature I was somewhat confused by the height requirements for steam traps in the main pipe and also for the psi in terms of condensate flowing back smoothly. For example the steam main rises vertically out of the boiler for several feet before it turns horizontal. Is the measurement taken where the pipe turns horizontal?

Steamhead

Crank it Down!

Even with the return modifications, that system should be able to run at very low pressure. As you've seen, proper air venting helps a lot.



Steam traps are rated for different capacities according to how much pressure differential exists between the steam and return sides. Static height adds a bit of pressure to the returning water.