Installing main vents

Jonathan Walpole

I have a one-pipe steam system that has no main vents. My local boiler service guy told me it was designed that way and doesn't need them but everything I have read says this isn't right.
I have some Gorton #2 main vents with a 1/2 inch threading but I don't have enough space to raise them up on a nipple. Can I tap these directly into the main or do I still need to cut the main and install a tee? Also, will the vents still work properly if they are not installed perfectly vertical?
Thanks for any advice you can give.

Steamhead (in transit)

In the old days

when boilers burned coal, the fire burned all day once it was lit. Therefore once the air was out of the system, it stayed out- so what if Junior's bedroom radiator took an hour to get hot?

Nowadays we don't have that kind of time, since the oil flame comes on and goes off. We need to vent the mains quickly each cycle. The system design has to change to accomodate automatic firing.

On systems with no main vents, we usually drill and tap 1/2" pipe thread into the side of the last tee on the main, with a slight pitch toward the tee so water will drain back. We come out with a nipple from the tapping and elbow up to the vent. Unless you have proper tools and experience, it's best to have a pro do this.

These vents must be more-or-less vertical to operate properly. If they're off vertical a bit they will still work, but don't try to install them horizontally.

Gorton #2 vents are the biggest vents made today. But to make sure they're properly sized, if you haven't done so already, measure the length and diameter of each steam main and post the results here. We can tell you for sure.

"Steamhead"

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