Jeff, It sounds like you have several problems.AS a hvac contactor I would highly recommend that you ask the sellers to have a local licensed hvac company perform a complete clean & check on the boiler operation and proper radiation in each room.This clean & check would include checking the chimney draft on the boiler & hot water htr.I am a hvac contractor in the chicago land area and have several accounts with realtors & inspectors that require me to inspect every sale. BY THE WAY GREAT JOB FINDING THE VENTING ISSUE.(did you check the draft with a lighter at the diverter?)GOOD LUCK!
I would have2 agree w/bill on the year,but if u need 2 confirm call dunkirk@716/366-5500.But I ? your reason about the last leg statement.DId you clean&check this boiler?what r the customers complaints?expansion or extrol?Whats the pressure cold?b&g strainer?cast rads.or cop.fin?I operate in chicago and deal with alot of boilers.I have found alot of copper fin tube base boards damps. closed & alot that the fins were totally clogged with dust/debri.