This is a vapor system in a very large house. There is just the owner and his girlfriend living there. There is a ballroom on the third floor that has as much square footage of iron as Steve has in his house. So naturally the owner wants to close down much of the radiation. This would cause short cycling problems with a single boiler. The solution we came up with was to install two boilers, one larger than the other. A two stage thermostat brings on the big boiler first, it fires in high fire. If that doesn't satisfy the load, then the smaller boiler comes on, but if thats now to much steam, the pressure will trigger a low fire gas valve we installed on the big boiler and drop the big boiler into low fire. This way the owner can do just about anything he wants to with opening and closing radiators and the boilers can react to it.