Steam Riser Vents Questions

NYC12786480

I have a steam riser in each of my apartment's bathrooms. We are on the top floor of a 12 story building. We recently bought this apartment in a co-op building constructed in 1917. Each bathroom has a steam riser and they both have a vent near the bathroom ceiling. Both these vents are pretty small- comparable in size to a Hoffman 40. And both of them are venting steam- in one bathroom, a decent amount of condensate is forming on a nearby shelf. The super brought a plumber by to look and he said they can't be replaced until heating season is over. Is this true?

Also, one of the bedroom radiators seems to be pushing air out rather aggressively and having difficulty closing. Would a too-small vent on a nearby riser be causing this aggressive venting from the radiator? Is inadequate venting on the riser causing the radiator to be doing the riser vent's job.

The previous owner didn't know jack about the radiators or didn't do an y upkeep or maintenance and kind of left me with this mess to untangle. We bought the unit in the summer while all the heating was shut off.

NYC12786480

Here are photos I took today of the aperatures in the riser vents.

Both these seem really small to be on a steam riser.

EdTheHeaterMan

is the problem you have only condensation forming because the vent is not closing, or, do you have issues with the radiator not heating the room or the heat in the room is too much?

Tough to tell you anything else without more information about the system.

And you can change those vents if you can time it during an off cycle of the boiler. But you must be quick about it because you will never know when the steam will start up again. I would leave this job to a professional.

NYC12786480

https://forum.heatinghelp.com/discussion/comment/1880561#Comment_1880561

I have a problematic radiator connected to one of these steam risers. When the boiler cycle starts, the air escapes the vent very loudly, it takes about 10 minutes to vent the air and it gets to around 70db measured about 10 inches away. It is a large cast iron radiator,16 fin about 50 inches wide 26 inches tall. I think it is pitched correctly towards the shut-off valve with an 1/8 inch shim. It has a Gorton 5 vent on it. It is in a bedroom next to the bathroom with the steam riser with the tiny vent. The stream riser vent is pretty quiet compared to the radiator, so I am wondering if there is some kind of role reversal here, where the radiator is doing the job of the riser vent because the riser is venting too slow.

I do have one radiator that is working great- but I don't think that radiator is hooked up to these risers, so that makes me think the building's overall system is working okay and there is a problem with these risers.

EdTheHeaterMan

it sounds like you might be correct. But I have limited steam experience on your type system. I did mostly single family or two family residential steam boilers and the occasional church. There are others on this site like @clammy, @JohnNY, and @RayWohlfarth that have more experience with your type system. One of them may have even worked on your building. Let's see what they say about this.