Vent sizing - pictures attached

wildrage

The house has 2 steam mains, 1 approx 70 feet long (#1), and 1 approx 50 feet long (#2). I believe #2 originally had convection radiators on it to send heat up duct work. The duct work is still there, along #2, but has since been converted to forced air, connected to a second furnace. Forced air also heats basement. Fortunately, this furnace only really turns on when the weather goes below 25. The steam from the rest of the house keeps everything warm most of the time. 280k wells boiler powering the steam.

Thermostat is located in same room as radiator #7
Forced air Thermostat located on 1st floor, away from radiators (not that it really matters)
The only steam on the first floor is in the kitchen. #6 is very large (5 feet long), on the landing between 1st and 2nd floors.


Main 1: 1, 2, 3, 4, 5, 7, 8, 10, 12

Main 2: 6, 9, 11

These are my thoughts on vent sizing. What do you think?

1. 6
2. 6
3. 5
4. 5
5. 4
6. 6
7. 6
8. 5
9. 6
10. 6
11. C
12. C

Jamie Hall

Main vents? At the ends of the steam mains? They need to be included in the plans.

nicholas bonham-carter

I would use Hoffman 1a’s on all, with several bigmouth main vents on the mains, and start there.
The main vents do the bulk of the air evacuation, as the rad vents are not designed for this.
What vents are on the rads now? If quality vents, leave them on, and spend the money on the main venting.—NBC

Steamhead

ISTR there is asbestos on the steam mains, which would need to be removed before one could install main vents- right, @wildrage ?

Doing this would be my first step.