Venting capacity of a 3/8" tap on a main?

Circa1902

I've been able to add two main vents on my system, (one on each main). System works much better now! However now that one problem is solved (or taking steps to be solved) I am now moving on to a balancing issue.

Long story short, the short main heats up much faster than the long main. I would like both mains to fill at approximately the same rate - so steam hits the two main vents at about the same time. Once I accomplish this, I can move on to balancing individual radiators throughout the house.

The problem on the long main, is that it's longer (more air in the main) and the tapping on that main is smaller, 3/8", which I believe is undersized. The short main has a 1/2" tapping and it works great. (Big Mouth on each main). The long main (3/8) takes much longer for steam to reach.

My question is, with a Big Mouth on a 3/8" tapping on the long main, would adding an additional vent on the long main help, OR, am I being limited by the 3/8" tapping?

Fred

You're not going to get much more out of the 3/8" tapping, however you can consider the Barnes and Jones Varivent which will allow you to adjust the short main down enough to balance the steam flow. The varivent can be ordered directly from Barnes and Jones.

Circa1902

Well I was hoping to speed up the long main as opposed to slowing the short main, but it sounds like that probably won't happen unless I re-tap.

Has anyone ever tapped right into a pipe, rather than cutting in and installing a tee with a union? Or is that not a good idea?

JUGHNE

These are 1/4" tap on top of 2" pipe. The 1/4" is maxed out with the G-2 vent. One tap for each. Very easy to do with a good non-import tap.
This was an old abused system (most are) that I wanted to protect the vents from debris. The supports are there because of all the weight on that 1/4" tap/nipple.

New England SteamWorks

I would just repipe the section with the 3/8" fitting and put in a tee with 3/4". Not a big project for someone who can fit pipes.

Circa1902

Yes, that would be the proper way to fix it... unfortunately that person is not me.... at least not in the middle of heating season!

Gsmith

Sometimes drilling and tapping into the pipe wall doesn't leave enough threads in the pipe wall for the nipple to grab tight to and the nipple will be loose in the threaded hole. Fortunately there is another fairly easy way to connect a 3/8", 1/2" or 3/4" pipe to a steel steam main--use a service saddle, available from Romac, Smith-Blair, Grainger and others. I've recently used the Romac 101U (http://www.romac.com/CATALOG/101.pdf) on a 2" main with a 3/4" outlet. Simply drill the appropriate size hole in the steam main (make sure the boiler is off), either on the top if you have the headroom or on the side (and use a 90 degree elbow to go vertical with your vent), strap on the service saddle and connect with threaded fittings. Be sure to order the saddle with a gasket rated for steam service (240 deg F), the normal gaskets are only rated for about 190 deg F. Happily the steam rated gasket only costs about $5 more than the lower temp gasket. I was able to find a local distributor from Romac who would order the size I needed and it only took about a week to get shipped direct to my house.

Circa1902

Thanks Gary, I am definitely interested in this option. Would you mind sharing that distributor with me? I contacted Romac directly but so far they have not been of much help.

AnthraciteEnergetics

I did the 3/8 tap into 2" main last year (system had no main vents). It works well for my short mains but yes nipple is not super secure, used excess teflon tape to jam the threads. I dont think i was using a quality tap. I like the saddle tap idea.

Gsmith

i have the info at work, not there today. Suggest you go on the romac website and call the area sales manager, for me in NJ it was Reed Rohrbaugh at a number I think near Pittsburgh, he was very helpful. I might not get the info till next Tuesday or Wednesday though.

Gsmith

Aha, I found it. I bought the Romac saddle from Brent Materials I think in Florham Park, NJ. See http://www.brentmaterial.com for address and phone, specifically ask for the gasket that is suitable for steam temperatures. Very easy to install and holds very well.

Circa1902

Thank you Gary, I am in Northern NJ as well so I'll call Brent Materials directly.

JWise

Oh how easy it was, thanks to @New England SteamWorks that is

> @Circa1902 said:
> Well I was hoping to speed up the long main as opposed to slowing the short main, but it sounds like that probably won't happen unless I re-tap.
>
> Has anyone ever tapped right into a pipe, rather than cutting in and installing a tee with a union? Or is that not a good idea?