Main Pipe Air Vents

tsayles50

One of the projects I plan on doing on my own this summer is insulating all the piping I have access to and replacing all the vents, main and radiator. I found my main vent locations, one of which has obviously been plugged.

1. For the main vent that is in I know it needs to be raised a couple inches to prevent knocking and water hammer. How much does it need to be raised and what am I supposed to use to raise it?

2. For the one that is plugged does that need to be raised as well?

3. When I figure out the kind of main vent to use based on width of the pipe and length of the pipe how do I know that vent will fit where the access is? Are these widths standard across the board?

4. Is replacing the main vent pipes something I ought to just pay someone to address since I am already paying him to fix the piping around my boiler?

-Tim

EdTheHeaterMan

this pugged pipe looks more like an abandoned radiator takeoff. But since it looks like it was the last radiator, you could use that opening for a main vent. You would need an elbow to point the 6" or longer riser UP to mount the vent.




This vent looks like it is in the worst place to install a vent. Vents located on such a tee fitting often fail prematurely. I believe a better vent tee location is 12” before the return drop to the wet return.

JUGHNE

An option, that does not require cutting open the pipe going to the last pictured vent, is to remove that vent add a 6" or so riser with a 90 and then extend back towards the main with horizontal piping maybe 12" or so. Then 90 up with a riser for the new vent.

This give a buffer for water slugs and particles to not enter the vent itself.

This is often done as a compromise to avoid cutting and threading pipe in place.

Just be sure the horizontal section slopes to drain water back into return drop.

It looks like you may have two 2" steam mains, the length of each will determine the size of the air vent for that main.

What are the 2 copper pipes at the ceiling in the first picture for?

random12345

This helped me: https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf
Agree with @EdTheHeaterMan if you can do it that way. Otherwise @JUGHNE's idea works too. This is mine that I built with a few parts from Supplyhouse. I like the B&J big mouth vent because of the high capacity. Before you do anything though, I'd wait to hear what the pro says. Vents are expensive and have a diminishing return. You want to get the air out of the steam mains as fast as possible, but is a few seconds faster really worth spending an additional $120? I think not.