Rattling heating pipe

I like your cat! No, that noise is not normal for steam — but it is almost certainly a noise "telegraphing" from some other noise source, maybe not even the boiler. Which is not in your apartment. Most likely in the mechanical room — and if you are a tenant, which I gather you are, that is something you can complain about — bit it is the landlord's job to fix it.

Outside plumber is not the best idea, do you have authority to even call someone to fix it? I'm not even sure that is a steam system. It sounds more like a flow control valve rattle on a hot water system. Are you the owner of the apartment that was made into condominiums, or are you just renting your apartment?

When the department of health and human services sends the building owner a violation, that speaks louder that any tenant complaining. It even breaks that language barrier.

Can you email the owner or management company? The language barrier will be overcome when your concerns are in writing. Management company first, then department of health department or renters rights or whatever NYC has that controls tenant complaints. You don't want to be THAT person right off the bat. Include the video in your email.

Everything must be in writing with nmes , dates and time. Save all your text and emails in case this gets to court. Anything that is communicated verbally should be followed up with a written email or text or letter.

Like this:

Dear Management Company Person 's name.

Thanks for taking the time to address my concern with the heating system noise. I understood you to say that you were going to do this and that and the other thing. Yada, yada, yada. (that is a New York City thing)

If I did not understand you correctly, could you please reply to this email with the correct information. If this information is correct, please reply that you received this correspondence. 

Thank You for addressing my concerns.