So while I'm trying to figure out my own steam system, I'm also looking at my parents' system in Brooklyn. They've got mostly cast-iron convectors, recessed on the first floor and freestanding on the second, with one thick-tube radiator in the front hall, and one oddball wall-mount thing (see pic 5) in the side hall. The system heats unevenly, or maybe it's just that the front upstairs rooms are above the outside hallways so more cold air leaks in. I did do an inventory of the convector sizes vs. vent sizes, but no pattern emerges. I'll save that for my next thread for now.
The thing is, recently there's been lots of clanging in the basement office, which is the former coal bunker next to the boiler room. We're trying to figure out what changed. They have a feeder, so the water level stays about the same as it always has. Now the pictures.
Pic 1: Aren't there usually two risers going up to the header? There's a knockout plate in the top cover of the boiler on the other side, but they didn't put any pipe there.
Pic 2: THe boiler room is right at the back of the house. The main on the left goes to the front of the house, drops to a dry return with a vent, then drops to a wet return about four feet later. The one on the right loops around the back of the house through to the office, then . . .
Pic 3: . . . short-circuits to a dry return line through this thing. What is it, and why is it there? Is that supposed to take the place of a vent? (like in the "cottage" in the end of TLAOSH) because I have no idea where the other end of that second main goes. It disappears into the wall, but doesn't come out the other side. Maybe it ties into the other main, maybe it goes upstairs, maybe it goes through a black hole to Mars and supplies the water vapor they've been finding there. If there's a far end with another main vent, I can't find it (without breaking walls, which my mom wouldn't really appreciate). If that apparatus up by the ceiling has gone bad, would that be what's causing the water hammer, and if so, where can I get another one?
Not to mention, where's the beginning of that dry return?
Pic 4: That there's what serves as a main vent for the entire house, or at least for that longer main. The vents on the convectors are a mishmosh of Hoffman 40s, Gorton C's and D's, a Gorton 6 in the room with the thermostat, and one weird sort of variable vent of dubious functionality called a Heat-Timer Thermo-Valve. The main vent, conversely, is a Dole #1933, with an aperture the size of a pinhole. I have to say that taking the smallest vent in the entire house and putting it on the main seems kind of bass-ackwards to me. I'd have swapped it for a Gorton #2, except for two problems: first, I couldn't find one locally (I was limited for time, so I only called the two nearest plumbing supplies. They both had only #1s, and one of them even asked me what the difference was between a 1 and a 2. Yes he did.), and second, there's really not enough vertical clearance under the beam, so I'm going to have to build an offset with some elbows and nipples before I can install it there. Which raises the question: if it's on an offset like that, does it still need to be 6" above the return? Or do the elbows, etc. protect it from water hammer? Because even not under the beam, there's no room for a #2 and a 6" nipple. Maybe I'd better just put a couple of 1s instead.
I also note in passing that none of the mains in the basement are insulated. They undoubtedly were once covered with asbestos, but the previous owner would have had to remove that before selling the house. Most of the main is inside a channel built downward from the ceiling and inaccessible without opening that up; the rest is very close to the ceiling. Not sure if there's going to be enough room to put insulation back on.
Pic 5: There's that weird wallmount unit. Anybody know what that is, and how to calculate EDR on it?
Pic 6: Is that copper pipe supposed to be in lieu of a Hartford loop? And if so, shouldn't it go higher up before tying back down into the boiler?