I would appreciate some informed thoughts on putting heat in an add-on room.
The original system was one zone with a flow control valve and a pump. That's four radiators on the first floor, three on the second. Each floor is roughly 1000 sq ft., radiators roughly 48" x 30" x 4" (bathroom smaller). A second zone was added to the basement (another thermostat, flow control valve, and pump). It's about 80 ft of 3/4" copper pipe; 20 of that is fin-tube. It works just fine.
When a first-floor room was added, the basement loop was split. Part of the loop went to fin-tube in the new first-floor room. The flow that doesn't go to the new room returns through the basement loop into the boiler. But the flow that is diverted to the new room returns through the original zone. Thinking about that just makes my head hurt.
When the pipe in the new room froze and burst, I just got rid of it altogether. But when I remarried, my cats were evicted from the new room, and it was turned into our new kitchen. My wife wants heat in the kitchen.
I have all the old fin-tube; I can just solder it back in. (I also picked up some cast-iron baseboard radiators that I understand give really nice heat.) I figure someone out there probably knows a bit more than I do, especially concerning the way the zones have been interconnected.
"A" is the original system: (1) thermostat, (1) 1-1/2" flow control valve, (7) radiators on two floors, (1) pump at the return inlet on the boiler.
"B" is the basement loop: (1) thermostat, (1) 3/4" flow control valve, ~20' 3/4" fin-tube baseboard radiator, and (1) manual valve added before the loop was split.
"C" is the fin-tube baseboard radiator that was added in the new first-floor room, later removed when it burst.
"FCV" Bell & Gossett "SA" Flow control valve.
"V" Manual 1/4-turn ball valve.
"P" Pump (Little Red Booster, I think)