Main Valve

ACG

I have a one pipe system. At the end of my main lines (I have two), there are 1/8" valves that I suspect are regualar radiator valves. I want to replace them with the property main valves but the ones that I find labled "Main" are generally 3/4" x 1/2". Is there a 1/8" valve that is made to use on main?

Also, the valve is located on the return pipe and not on the supply main. Does that make a difference?

Thanks,

Adam

Rod

Main Vent (valve)

Hi Adam -     Post a picture of the valve. Normally there would be a reducer bushing between the present vent and the piping that you could remove and replace with the size bushing you need. While it might be ideal to have the main vent (s) on the end of the main,  they will generally work fine on the return

- Rod

ACG

Main Valve

Thanks Rod.

I will post a picture later but I am assuming that the reducer bushing is the bolt with the hexagon shaped head that the valve is screwed in to. If so then yes the returns have them.

So I am assuming I should replace the reducer bushings with ones that can fit a 3/4' x 1/2" main valve and put on a main valve?

Also, would it matter if I used a strait vent in stead of an angle vent since the opening is on the return and the air will vent sideways in stead of up, or should I put an elbow on the reducer?

Rod

Main Vents

The hex headed "bolt" is most likely a reducer bushing. Generally most main vents have to be installed in the vertical plane.as they have floats inside them that lift and close if water is present. (They, of course, also close when steam reaches them.)

You want to use either a Hoffman #75 or a Gorton #1 or a Gorton #2 as a main vent. Let us know the size and length of your mains and we can give you an idea of what venting capacity you will need.



You may want add some fittings and pipe nipples to move the vent a short distance away from the main piping to protect the vent from water. If you do that, you may want to not reduce the piping size until the point where you attach the vent. I've attached two diagrams of main venting setups that might be of help to you.

- Rod



Edit- Both the diagrams suggest you move the vent back 15 inches from the end /turn of the main pipe. While this  is "ideal" as water rushing down the pipe won't go up into the vents, however in "real life", vents are quite often found on the end of the piping.  In this case using an "antler" helps to protect the vent.  Arrange the piping on the vent line so that any water that enters the vent piping will drain out.

ryanr256

What I did

Here is a before and after of my main vents. Maybe it will give you some ideas.

And, yes, the after shot shows the insulation in progress. :-)

-Bob