Need steam heating specialist in Manhattan

Hi all! Would be very grateful for recommendations. I am in need of a steam heating specialist here in Manhattan on the UWS.

I live in a circa 1900 brownstone coop that is self managed (it’s basically like a single family home we share with a few other units). We have a relatively new steam boiler. As we are self managed, I have access to all the systems.

The problem is the system is quite loud (big and unpredictable knocking/banging that suggests there’s moisture building up somewhere). And I don’t know how to diagnose the issue. Is it systematic? An issue with the radiators in our unit? The radiators above us? We need an expert to review the system and make recommendations for us and the building.

Any help would be greatly appreciated!