Sorry for the length! I'd like to increase the heating and efficiency of what I think is a Richardson 2-pipe vapor system. I'm hoping The Wall can confirm the system type and help me solve a few strange issues.
Here is a sketch and some photographs of the system: https://drive.google.com/folderview?id=0BxSm-abGocfweVVES0xCc1UtQlE&usp=sharing
The system is in a 1919 brick townhouse that I've owned since 2008. It has clearly been modified, unmodified, and re-modified several times. There was a boiler replacement around 2002 resulting in the current Crown boiler -- 103,000 input, 84,000 output BTUs. The boiler seems to be working well. The boiler is running off a pressuretrol, not a vaporstat, and the pressuretrol is set at what looks like 1 or 1.5 psi. I have never experienced the boiler cycle stopping before the temperature is reached even with longer cycles in the real cold, so I don't think there is much pressure building in the system, if any (it might be vented to the outside....).
1. The radiators all heat up, but not completely. There is about a 4 to 5 degree difference between the warmer downstairs (thermostat location) and colder upstairs, despite the upstairs having larger supply piping.
2. 5 of 6 radiators have Richardson type supply valves and water seal elbows, but also have Hoffman #40 or equivalent air vents that shouldn't be needed in this kind of system. Some of the air vents push out quite a bit of air during each cycle, others not so much at all -- but they all heat. The Richardson elbows are installed eccentrically at the bottoms of the plugs, not in the center, but they really do look like Richardson water seal elbows. Radiator #3 is another story -- its connections were hacked together with copper after a bathroom remodel at some point in the past. Despite that, Radiator #3 actually heats really well, and its connection to the dry return doesn't get hot, so steam is not circulating.
3. The dry returns junction has what I think is an old Hoffman #6 Quick Air Vent / Vacuum Valve (can't tell if its doing anything), but it also has a mystery pipe running to the chimney stack, and I have to assume venting to the outside. There is no evidence of a previous radiator that would have had a dry return in the chimney area.
4. Steam Main #1 does not connect to Dry Return #1 except through the Radiators. However, the end of Steam Main #2 directly connects to Dry Return #2 through some kind of water seal loop with no trap or valve. For whatever reason, it seems to work -- the Steam Main side of the loop is hot, but the Dry Return side is always cold. In fact, the dry returns are always cold, so steam is not circulating through the dry returns.
QUESTIONS / Help Needed:
Based on reading, I think the plan would be switching to a vaporstat, cleaning the Richardson elbows, removing the radiator air vents, adding vents to the ends of the steam mains, and replacing the Hoffmann #6 with a Gorton #2 or even a pair of them. However, I'm concerned about a few things:
A. What is that mystery pipe leading to the chimney stack? If it is atmospheric venting to the outside, what would that mean? What should I do -- leave it? Cap it and replace the Hoffman #6 with a lot more venting at the Dry Returns Junction?
B. What is the purpose of the water seal loop at the end of Steam Main #2? Should I sever the connection between Steam Main #2 and Dry Return #2 and then vent the end of Steam Main #2? Should I leave it as is?
C. Is everyone sure that these are Richardson Elbows? Is there any guide to servicing the air hole in the Richardson Elbows? I don't see any way to get into them without taking the whole Dry Return line apart, and that's going to be an issue. Has running the system at potentially more than a couple ounces of pressure damaged the elbows at all? Would using clean Richardson Elbows and no radiator vents help with equalizing the temperature between the floors-- will those vents efficiently handle the volume from the larger supply pipes to the upstairs?
D. If the Richardson Elbow air holes are clogged, but still providing water seal and condensate return-- how bad is it to keep running the radiators with the Air Vents, and equalize the temperature by increasing the size of the air vents in the upstairs? Is that any kind of viable option to even out the system?
Thanks in advance for any help on any topic! I hope you find the system interesting. I know I have!