rbeck: Thanks for the link. Looks like I have a wet return setup. From the main vent, that pipe runs for another 5-6' and then drop to the floor level for another 25' back to the boiler. What do I need to buy if I want to insulate the main?
plumbingods: I only have 1 main line. The bathroom radiator usually hiss for a few minutes and then stop when the boiler is firing. The third bedroom, it never hiss before with an old small vent. Since I changed to a larger vent, it hiss continueously as long as the boiler is firing. None of them blow out moisture though. Also, all the radiators get hot around the same time.
Question, not sure if this is normal or not. The boiler is Weil McLain EG45. The last couple of days have been cold in NYC. Outside temp is in the 30's with wind chill in the mid 20's. It took the boiler about 70 minutes to heat from 60 to 67 in a cold start. The boiler would fire up for about 20-25 minutes and then stop. It will fire up again in a few minutes for several minutes and then off once it reaches about 2.5 psi. This will repeat until the set temp is satisified at the stat. The stat is set to 2 cph. Last year, I had it at 1 cph but the temp swing was too much. Is this normal?
Here is a pic of the boiler (the pressure relief valve is piped down but not shown in pic):
