Ok, here's my situation.
I live in house built in the early 1900's, though I'm not sure of the exact year. It's been through some remodeling, particularly finishing the attic space into a large family room type space.
The boiler is in the basement and the main floor has the original cast iron radiators in all but the kitchen and dining room which have the baseboard hot water heaters. The finished upstairs also has baseboard hot water heaters.
Two years ago (2010) a new Crown Boiler (AWI162ENST1PSU) was installed due to the old one having a gas leak. However, when this was installed, there were no valves placed on the supply and return water lines for the upstairs. However, the plumber who installed the boiler DID attach a thermostat to the boiler, one for the main level and one for the upstairs. We were constantly fighting with the temperature on the lower level and wound up having to use a (good/expensive) space heater in the upstairs to keep it warm in the winter.
Recently, we called a new plumber to come out and look at the system (as the installing plumber has failed to "come look" at the issure for over 1 1/2 years despite repeated calls) to try and figure out why we didn't get heat upstairs and got too much downstairs. We were told when we moved in that you had to "mess" with the upstairs thermostat to get the main level one to work properly. Last year wasn't so bad, but this year we wound up waking up to an 85 degree main floor in the mornings.
Ok, so long story shortened. The boiler installed is verifiably a hot water boiler. The radiators on the main floor, based on my research are hot water radiators, though research also says that they can be used for steam heat. They each have a hot water air vent (standard screwdriver type)located about 2/3 of the way up the radiator on the opposing side of the supply line. On the main floor they are two line radiators, supply and return I assume though I'm not certain. The upstairs baseboard radiators are for hot water, and have one supply line coming from the basement to the RH side of one radiator, then copper line runs the perimeter of the upstairs space with 2 additional HW radiators connected inline. The return line is on the LH side of the last radiator.
So, the plumber indicates that our boiler is running at too high of a pressure. He says he needs to replace the expansion tank since bleeding the pressure relief valve doesn't bring the pressure down, and he disconnects the thermostat to the upstairs (both thermostats were connected to the boiler at the same point and there are no valves to control the thermostat for the upstairs area).
When I asked him about creating a separate "zone" for the upstairs, he tells me that the whole house would have to replumbed, including tearing out walls to do so. He tells me that it is a steam boiler, and that the radiators running on the main level are running on steam, and that the radiators upstairs are for hot water. This isn't true, as the supply and return lines run through the main floor outside of the walls. When I explained that to him that's when he said it was a steam boiler and all the main floor radiators were operating on steam, not hot water.
Is this even possible? I understand that the house could have been plumbed that way, but can you connect a hot water boiler in such a way to heat with steam? I also understand that many people who have worked on this house for the elderly owner took advantage of her absence and lack of knowledge while they worked (such as the guy who connected a non-zoned heating system to two thermostats "just because" that's the way he found it).
How can I tell if my radiators downstairs really are operating on steam and not hot water? Would the boiler, rated at 162,000 input and 132,000 output have enough pressure to re-plumb the supply and return pipes for the upstairs into a separate zone?
The radiators work fine, are not noisy at all, and have no visible signs of leaks, now or in the past.
Anyone with any suggestions (who's managed to make it all the way though this post) is not only tenacious but also very much appreciated.