Main vent location

ChrisJ

I have a main vent which screws right into the steam main.  Should this valve be mounted directly into the main like this or should I use something to extent it up above it?

If it should be extended higher I can easily buy a 3/4" nipple and a coupler and raise it up but I am not sure if I should use galvanized pipe or black iron?



Thanks,



Chris J.

Patrick_North

Yes, an offset is good insurance.

Doing so helps protect the relatively delicate guts of the oh-so-critical main vents from water hammer, slugs of fast moving water, etc.

Search the Wall for "antler" or "menorah" to see pictures of some thoughtful applications.

Good luck,

Patrick

ChrisJ

Galvanized or not?

What type of iron pipe should be used for this galvanized or black or does it not matter?



Chris J 

moneypitfeeder

pipe

Black iron, and here's a great example of how your setup should be. http://www.heatinghelp.com/files/posts/7338/Menorah%20&%20Antler%20PDF.pdf

Greg Maxwell

Vent Location

Make sure that the vent isnt directly on the elbow of the return. A good rule of thumb is 6" back, and 6" up. Also, use a large capacity main vent to vent that air as fast as possible from that main.

ChrisJ

How fast?

I'm going to assume if one of my two mains is around 10 feet long and the other is around 25 or 30 feet long then I want to vent the 10 foot one somewhat slow and the longer one as fast as possible in order to keep the system balanced?

Rod

Main Vents

Hi Chris- In most cases you should vent all your mains as fast as possible and do any adjustment for time /length of piping etc. by adjusting the venting capacity of the radiator vents.

For venting, either galvanized or black pipe will work fine. 

Water doesn't like to travel around corners so if you use say an "antler" configuration, have the antler going towards the boiler (up slope on the steam main) as that way the  condensate coming down the steam main has to go 180 degrees to get to the vent. Also by being "up slope" any water getting near the vent will drain back into the steam main and won't collect near the vent.

- Rod

ChrisJ

What about elbows?

If I want to do 2 vents instead of a 4 vent menorah can I use 1 tee and two 90 deg elbows instead of 3 tees and 2 plugs?

This may be a really dumb question but I canont figure out why the menorah has four tee's and 2 plugs instead of 3 tees and 2 90 deg elbows.  Maybe due to cost?

Steamhead

What size pipe

is in your steam mains? 

ChrisJ

steam main size

Hi Steamhead,



2 1/2"  mains

I have one which is 11 feet long and feeds 3 radiators two of which are on the second floor.

The other long one is around 25 feet long and feeds 7 radiators 3 of which are on the second floor.



I have two new in box Hoffman 4As but it sounds like they vent too slow for even my one short run?

Steamhead

They certainly are

and anyway you need twice the venting on the longer main as you have on the shorter one. I'd use one Gorton #1 or Hoffman #75 on the short one and two on the long one. 

ChrisJ

All set

Ok,



I finally ordered the lost art of steam heat and I will be ordering three Gorton #1 vents.  I have the stuff in black iron needed to fit the two vents on the one main.



Thanks for the help!

ChrisJ

Main vents replaced finally

With the help of people on this forum as well as the info found in Gerry Gill and Steve Pajek's Balancing Steam Systems PDF I have successfully upgraded my main venting.



The system has an 11' main and a 29' main.  The 11' main had a clogged vent and the 29' main had a Dole 1933.  I installed a Gorton #1 on the 11' main and three Gorton 1s on the 29' main. 



I'm curious, where my mains drip down to the dry returns they do so at a slight angle and not straight down.  Why is this?

Rod

Main to Return

Hi Chris-

   I can only imagine that it slopes to the side to save headroom. The transition from the main to the return just needs a bit of slope and If it when straight down, it would drop the overall pipe even lower. This would be especially important if the basement ceiling was low and therefore the  "A" dimension tight.   Just a thought.

- Rod

ChrisJ

low ceilings

Rod,



I'm almost certain I have one or more dents in my head from the pipes in my basement.

kcopp

just one more....

thing. Insulate your mains w/ good quality fiberglass pipe insulation. This will make a huge difference. kpc

ChrisJ

1"

I've got enough 1" quality insulation to do both mains and the new header. Not sure what brand it is but the fiberglass is a brown color not yellow if it matters.



I need to get material for all of the fittings still, but it'll get done.