I've been reading through this forum all day and have learned a lot. Thanks to everyone here!
Our situation: We just bought a hundred year old house in NJ with a steam boiler system (which we also have at our current home). We're experiencing a terrible smell that started after we installed a new steam boiler. The old one was shot (had visible holes to the chamber) so we had to install this before we closed on the house. Up until then, there was no odor in the house. Our plumbers have even stated that it did NOT smell in the basement or anywhere while they were installing the new boiler.
Since installation, there is a horrible smell that is hard to describe, even after reading all of the descriptions on here. Our smell is not rotten eggs. It's not musty. It's sickly sweet and almost vomit-like. Cleaners who came in assumed the house must have had cats, but there were no pets or smoking, and as I said, no smell until this new boiler. We smell it most in the basement and in the front and back foyers on the first floor. It fades as you go up, and you can't smell it at all on the third floor. When we walk through the front door, sometimes it's so strong that it makes me nauseous. Our plumber is perplexed but is coming back Tuesday to open the boiler and check everything.
Luckily, we aren't living in the house yet, but I can't move my kids in there with this smell, and I'm worried that we won't be able to identify where it's coming from. We spent 3 days with the heat turned down and the windows open airing the house out. While the doors are open, it seems a little better, but when we close it up the smell returns, which makes me think the smell is being actively produced by a leak of some sort. We checked the vent stack, no leaks. The sewer lines are all intact and caps in place (plus, it really doesn't smell like sewer). The large radiator pipes in the basement and the furnace itself all smell bad when the system is hot, but that might just be whatever gas this is interacting with the heat.
Any ideas? We feel like we've read the entire internet trying to solve this and we aren't getting anywhere.
I'm not at the house now, but hopefully I can post some pictures of the furnace tomorrow.
Boiler: Burnham, will get model # tomorrow, gas fired, two-pipe system
Thanks for any help!