Peerless fuel oil model WBV-03-085-SP installed ???? (maybe the 1980's - it's not too old).
Input: 101,000 BTU/hr Output: ?????? BTU/hr

Honeywell PA404A1009 pressuretrol
cut-in set at 0.5psi with differential cut-off set at 1psi (for 1.5psi cut off pressure)

Main vent was clogged (recently I think) and is an old Hoffman #4
Radiator vents are mix of older-looking Hoffman 40 models and ????

December 2005: replaced main vent with Gorton #2 and cleaned pig tail. The pig tail was clogged and caused the pressure relief valve to pop as well as some apparent water hammer (reported by renters the last few days they were there). The high pressure and water hammer most likely clogged/destroyed the OLD main vent. The new Gorton made a tremendous difference and uncovered 2 bad radiator vents which will be replaced.

Don't really care about getting the absolute max efficiency from the system, but insulating the riser is on the list of things to do to minimize potential damage/problems with wet steam, water in main, etc., etc.

Main vent is at very end of return and not just after the last rad riser, but it's just not practical to repipe that area. Since the return goes vertical at the main vent (the vent is not back ~15 inches from the end tee) hopefully the vent will not be damaged by start-up rush of condensate/steam hitting the end of the line.

UPDATE March 2008: replaced all the old radiator vents with new Gorton ones after sizing the runs and volume of the radiators. Still thinking about adding a second Gorton main vent since the main loop is so long - as I recall it's about 100 feet (!). Everything is running fine, although I don't think the renters are going to run the boiler much because they are poor students that have bar tabs to pay.