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One floor hotter than the other with one-pipe steam
We have a one-pipe steam system, in a three story row house. When it is cold out (mid-30s and below), the third floor gets quite hot (80F). When it is in the mid-40s outside, it seems that the steam doesn't even make it to the third floor, with indoor temps in the high 60s. The thermometer is on the 2nd floor in a hallway, away from any radiators, and is set to a fairly constant 67F.
The first floor recently replaced their radiators with forced air, so it is possible that the boiler is now over-sized. What are peoples thoughts? Is this an issue of an oversized boiler, a venting problem, or a thermometer problem?