master venting

Jamie0

I'm considering a master venting approach. Is it necessary to replace the angle valve with a gate valve or is there a way to put the vent(s) between the original valve and the radiator?

Dave in QCA

More Information Needed

A more complete explanation is needed to understand what you referring to.  Master Vent, for the entire system?  Angle valve, where?  which one?  Gate Valve, where?  What are you trying to accomplish?

Paul48

Can

You steer us to the place you got this idea? Monty Python.....And now for something completely different! Why not start with the things that are not right, before re-inventing the wheel? Main vents? Tee'd Main?Insulation?

nicholas bonham-carter

Counter-flow venting?

Is this a counter-flow system, which you want to add main vents to at the end of the main, above floor level?

Can you post some pictures of the boiler piping, and radiators, or even a layout drawing?--NBC

Steamhead

Master Venting

comes from Frank Gerety, not John Cleese, Graham Chapman, Eric Idle and company. Dan mentions it in Lost Art, page 118. Frank wrote a book called "How to Get the Best from One-Pipe Steam" years ago. It's out of print now, but I have a copy.



Basically, Frank pioneered the method of measuring steam mains and risers to see how much air they contain, and then installing vents sized to release that amount of air quickly at very low pressures. I don't know of anyone doing it this way before, so along with many others I ascribe it to Frank. Several people built on this, including myself, and it eventually led to Gerry Gill & Steve Pajek's laboratory research, resulting in their e-book "Balancing Steam Systems using a Venting Capacity Chart" which has become the standard. For those who don't have this e-book, you can get it in this site's online store.



Getting back to the original question: Gerety's method will work, if you have room to move the radiator to make room for the straight-way valve. Always use a gate valve, not a globe or stop valve since the latter type creates a water pocket which WILL cause banging and spitting vents. And you want the vent before the radiator valve, so even if the radiator is shut off the vent will still vent the riser.



Another way is to drill and tap the riser on the floor immediately below, about a foot from the ceiling, and install a vent there. Gorton #D vents work well in this application.

Jamie0

Tapping black iron pipe

Awesome. I know my description was a little confusing. This is my first full winter with a steam system (my first home actually). Thanks for the picture too. This is exactly what I had in mind.



Seems like tapping the actual pipe might be easier than replacing the supply valve and adding a gate valve. Could you give me instructions on what tools I will need in order to tap each of my risers and main pipes? How and what to drill with? Anything I should watch out for? I'm definitely looking forward to finally having some good venting in the system, especially since the boiler pH is pretty high. I may have to get that venting ebook too. Thanks for the help.

Rod

Tapping a Vent Thread

Hi- The easiest way is to find a friend who knows how to tap pipe!   It sounds like you haven’t done this before so here are the basics.

Pipe Thread is different than regular straight thread, like the kind you find on a bolt as it is tapered (like a wedge) so that it tightens up as you screw the pipe into it. 

To do the job you will need a 1/8 -27 pipe tap  and a “Q” sized  drill.  (The "1/8" is the size of the pipe and the "27" is the threads per inch)



Drills come in both fractional  (7/16") and Letter Sizes (A, B, C...)  Since there isn’t a fractional size close to the size  pilot hole you need for the 1/8-27 tap,  you will need to get a Letter “Q” sized drill for the job. A plumbing supply or an industrial hardware store  should have this drill. Big box stores, like Home Depot, might not have it.



Here are some fairly good instructions on how to use a pipe tap and what you will need to do it.

http://www.ehow.com/how_7419730_use-taper-pipe-tap.html

Since you are tapping a pipe wall,  you don’t want to run the tap too deep. Just put in enough threads to secure the vent. It's a fairly easy job to do. Just read the instructions well and take your time 

- Rod

nicholas bonham-carter

end of main venting

have you tried putting a gorton d on that end radiator? generally it is not advised to over-vent a radiator, but it might be worth a try in your situation, especially if the intermediate radiator vents are slow.

i have used a couple of d's on the third floor, without any condensate over-production issues, although i do have the luxury of a parallel flow system.--nbc

Jamie0

Steam main layout and venting

Great info. Thanks. I have mostly adjustable Hoffman radiator vents. My system has 5 mains that start from the boiler in the middle of the basement that sort of span each part of the house - I believe most are counter flow in nature, with some having drips connected at certain points. The two convectors are 2-pipe luckily.  I would say that there really isn't  one designated end of main in my system but 5 end of mains maybe?



I'm wishing I went with the slower (and apparently quieter) Hoffman radiator vents, but live and learn.

Jamie0

Pipe Tapping

Hi Rod,



What would I be looking at if I wanted to put in a main vent with the 1/2" 3/4" size? What's the largest tapping you would make in a 1 1/4" pipe? Maybe a smaller main vent like 3/8 would be better.