How to add main vents to single pipe steam system?

Eric_EWM123

Greetings! I have a single pipe steam system that I've been tweaking lately for better efficiency. After recently reading Dan's book and reading lots on this site there seems to be many practical things I can do to improve performance and lower my gas bill.

My system does not have any main vents and I can't find any signs that they were ever installed. The house was built in 1946 and the boiler has 1994 on the nameplate. There is a wide variety of air vents on my different radiators installed from the previous owners and then I myself have purchase some different types to tinker with.

But before I mess any more with radiator venting and balancing the system it seems clear I need to put in some main vents down in the basement.

May I have some comments on the attached PDF which shows the plan I'm considering??? I'm thinking/hoping this will be a good DIY weekend project and can be done for under a couple hundred bucks.

Further background info:
This will be my 3rd winter in the house and the system has never let me down in terms of keeping the house warm. But something has never seemed right given how my radiators sometimes heat, sometimes don't. I typically have every single interior doorway open 24/7 so I figure the rooms all balance themselves out even though the radiators are struggling to properly do their job consistently each cycle. My radiators always hiss, but sometimes its loud and gurgly, other times not so much... more on that at the bottom.

Also last week I adjusted the Pressuretrol... before Cut-In was 5psi with a 1 psi differential. Now I have it at 0.5psi and the same 1psi diff.

Without vents on my mains obviously much more air goes through the radiator vents than typical. I suspect my vents clog frequently however given so much air was being squeezed through, especially with the 5psi cut-in, they'd unclog themselves frequently naturally. This could explain why radiators would sometimes get hot, other times not at all.

-Location is central Pennsylvania.
-Cape cod style
-Winter natural gas bill is around $150-$220/month which I think can be lowered $50+ per month with some TLC.
-Back in October I blew cellulose insulation into my attic. Also air sealed everything up there as best I could too and was sure to put in proper venting down to the lower knee walls.
-Near boiler piping all looks good per the guidelines in Dan's book, including the magic 28" rise from the site glass.

Thanks in advance!

Fred

How long are those Mains? I suspect a Gorton #1 won't do the job unless those mains are around 10 feet long. You are correct, all the air in the header and mains and the rads, themselves has to be pushed out through small radiator vents before the rads can do their job of heating. That waste fuel and delays getting the house warm. Get the mains vented and then you can balance the rad venting.
Do you still have gurgling and noise after you turned the Pressuretrol down? If so, make sure your rads are pitched slightly back to the supply pipe and that all the pipes ( Radiator run-outs) are pitched back towards the main and the main is pitched towards the dry returns.

Abracadabra

Where does the pipe on the right end up? Maybe there's a vent there?

JUGHNE

This worked for me, 1/4" IPS tapping in a 2" pipe. The strainers are to protect the vents from debris and the 90 plus distance of piping are to keep water slugs from finding the vent. This was an old system with work being done that would disturb old rust.
A 1/4" tap will handle one G2 vent. I didn't want to tap 1/2" into a 2" pipe.....didn't think there was enough meat of piping in the radius of pipe.

Eric_EWM123

Fred,
Main 1 is 40-45 feet long.
Main 2 is 28-30 feet long.

A single Gorton #1 on each main not giving enough venting isn't something I've thought of...

Can the mains be over vented? What if I just do a Gorton #2 on each main which says it's 4 times the venting of a #1? Otherwise I'd need to do 2 or 3 #1 vents on each and that'll be the same cost in the end as just getting the bigger #2s.

As for the gurgling, it has gotten much better after turning the pressuretrol down but it could be all in my head at this point. I've checked all my radiators pitch and they are all good. I've never put a level on all my basement piping however I can check that.

Abracadabra,
The pipe your seeing just stops at the wall. In the first picture you can see plywood covering an opening and that goes into a crawl space under the kitchen. I took the ply down to inspect and there is definitely no venting going on back there.

JUGHNE,
I like your picture, thank you. Once I get a handle on how many G1's vs just a G2 on each I'll take your pic to my local industrial supply place so a parts guy can get me all the bits I need.

BobC

You can't over vent the mains but you don't want to spend more than you have to because you can get to the point of diminishing returns.

If it were mine I would put a bigmouth on both those mains, that will give you 6X the venting you have now. Because one main is about 50% longer I would be prepared to add the two Gorton #1's onto the longer main along with the bigmouth vent.

You might need the additional venting on the long main to balance the two mains so steam gets to everything at the same time.

Bob

Sailah

The Vari Vent might be a good option for the smaller main as the threaded cap allows you to tailor the venting capacity to match the larger main as a nice companion to the Big Mouth as suggested.

The Big Mouth vents 3.6 CFM @ 3 ozs
The Vari Vent vents ~0 to 2.5 CFM @ 3 ozs

The Big Mouths are available through Heating Help

astore.amazon.com/heatinghelp-20?_encoding=UTF8&node=13

Fred

@Eric_EWM123 , do as @Sailah suggests. He is from Barnes and Jones and desighed both the Bigmouth and the Barnes and Jones Vari vent. They are both solid ain vents and actually cost a little less than the Gorton #2, with greater venting capacity. Way more bang for your buck! The answer to your question is no, you can't over vent your mains but as @BobC says, you can get to a point of diminishing returns. In your case, you need a Bigmouth on the long main and a Barnes and Jones Vari Vent on the shorter main.

Eric_EWM123

I’m back with some verified measurements on my piping and I’ve got a couple more questions.

Also attached is a new PDF showing what I’m working with.

Thank you all for the help thus far!

Main 1
= 55’ of 2”pipe
= 1.29 cubic feet

Main 2
= [38.25’ of 2” pipe] + [10.5’ of 1.5” pipe]
= [0.89 cubic feet] + [0.15 cubic feet]
= 1.04 cubic feet combined

Point “A” on my attached diagram I’m thinking to install a Barnes & Jones Big Mouth per the recommendation of @Sailah. I’ll replace the elbow with a T and the rest is self-explanatory. I will also pipe in some distance lateral and vertical, plus a y-strainer like @JUGHNE shows in his picture. I don’t know if I have excessive bits of rust in my pipes but for ~$15/strainer I think it could be worth it.

As for where to add the other vent on the shorter main, I’m not sure if I should vent at “D” or “E”. In either case I’d like to avoid tapping threads into the main pipe and instead drill a sufficiently large hole and then cover it with a “saddle-tap tee adapter” (like McMaster-Carr 4572K212). This will allow 1/2” pipe up to the main vent without having to worry about insufficient wall thickness for the threads.

Access to install is much easier at “D” but this means the 10.5’ of 1.5” main pipe will need to vent through the two radiators.
Installing at point “E” is possible but it’s tighter quarters to work in. There is 10” clearance above the main pipe and 4” off the wall. This area is under the top of the basement steps.
Can anybody weigh in on this?

@Sailah if I put the 2nd vent at “E” should I install a Big Mouth there too, or would the Vari-Vent still be valuable given my actual pipe volumes?

Lastly, as shown in the 4th and 5th page on the attached you can see my pipes are wrapped in what appears to be kitchen aluminum foil with insulation underneath. Both “D” and “E” it appears that the insulation is a clay like covering on the pipe. It’s a grey/white color and some small chunks easily broke off when I poked it. I just googled “asbestos” and now not sure what to think… If the material is safe to remove I think I can easily cut a section of foil, chip away the insulation, drill, then attached a saddle-tap. Then once done I’d re-wrap the area with fiberglass and the aluminum foil tape.
Anybody have any wisdom on this aspect?

Thanks again!

JUGHNE

The foil wrap may have someone's attempt in encapsulate asbestos insulation.
The straight lengths may have a cloth covering over what looks to be corrugation of cardboard which is usually asbestos insulation.
The fittings might be solid plaster looking material which is powered asbestos mixed with water and applied as mud, it too may be wrapped in the gauze.
The danger is producing dust.
In the event of an emergency leak it has been said that a contractor may remove the minimal amount necessary. IIWM I
would use a bottle to spray water and soak the area down.
Carefully cut and keep the stuff wet. Into a plastic bag, water and all, then double bag for disposal.
I believe a homeowner can do this even more so than a contractor.
This is just what I have been told. FWIW.
Remember plenty of water and no dust.

The fittings or "knuckles" usually have the plaster and that can be pretty tough cutting the layers out......I would avoid those areas......which gets us back to a straight length of clean pipe for tapping a hole.