Venting Mains

jmob77

I have a one-pipe system with convector radiators in my home. It works pretty well (this is my first winter in charge of my own heat), but it's a bit uneven at times with some minor hissing in two or three spots. I haven't had the right weather to take off any valves and check them, but I'm curious about the main venting. I see one valve on one end of the main. The other end is boxed in; previous owners did work on the ceiling on that end of the basement, so the whole run of main pipe is encased. I don't want to open that up if I can avoid it. Does it make sense to add a tee and more valves on the end that is accessible to ensure proper venting of the main? Is this something to do before working on the individual radiator valves?

BobC

Getting the main venting right will make balancing the system easier. What pressure is the system operating at? How many steam mains, how long is each one, and what size pipe?

Bob

JUGHNE

To avoid confusion here just call a vent either a main vent or a radiator vent. A valve has a handle on it (usually) The conversation can go astray if the words are interchanged.

Post a picture of the main vent you can see, that will be indicative of what might be hiding on the other end in the box.

Also answer BobC's questions if you will, please.

jmob77

I have two mains that are 2" pipe, each about 35' long. I insulated the exposed stretch, most of which is in the garage, when I moved in this Fall. This is where the only visible main vent is. I've not had the time to fiddle with the pressure, but the cut-in is set to 1 psi and the gauge usually reads right around 2 psi. I realize I should probably get in and lower those settings. Photo of visible main vent to come...

Steamhead

You need to open up the enclosure at the end of the other main. There is probably a vent there, and if it fails it may leak, so you would need to get at it anyway. Put a Gorton #2 on the end of each main and watch how well it works.

jmob77

Can I test the current main vent by removing and blowing through it? It isn't noisy, but I'm not sure that means it's doing its job. No idea how old it is.

Fred

jmob77 said:

Can I test the current main vent by removing and blowing through it? It isn't noisy, but I'm not sure that means it's doing its job. No idea how old it is.

What type vent is it? You can hold it upright and blow through it to see if it is open but that certainly doesn't mean that it is adequate to properly vent the air out of the main in a reasonable amount of time.

jmob77

Here are two photos of the main venting setup. There is a single Gorton #1 which I imagine is probably not enough to do the job well. As you can see, I have pretty limited headroom between main pipe and the ceiling of the garage. Would a #2 fit if I moved it over with an antler? Perhaps it's better to put two or so more #1s on a similar setup? I'll add that it wasn't my brilliant idea to run all that cable right above the vent: previous owner!

jmob77

PS, for some reason, these photos rotate 90 degrees when you click on them. Sorry, don't know why...

Fred

You can build an antler and move the venting over. If you use a Gorton #2, you will need about 7" of head room for the Gorton #2 plus the height of the piping you use to move it over. If you decide to use Gorton #1's it takes about 3 Gorton #1's to equal a single Gorton #2.

jmob77

I have to take exact measurements. Is it possible to lower the connection a bit by making an antler that bends down 45 or 90 degrees and turns up again so that the vent faces upward? (Picture a J or L shape at the end of the antler). I think this is the only way I could get 7" of headroom. Would this cause problems with air escaping the vent properly?

Fred

Any portion of the antler that drops down will retain water in that pipe. Won't work.

JUGHNE

With any bend or slope down that portion of pipe will eventually fill with water from steam condensing and not being able to drain back into the main. That water will effectively create a water seal trap. The steam may push it out of your vents. But in any event you will have diminished the venting capacity of your venting station.

As an alternative you could cut open the ceiling between joists spaces. Avoiding the electrical cables of course. The area between joists would give you the height and spacing for large vents. Assuming you have a parallel flow steam main which would slope down towards the end of the main before connecting with the return pipe.....I would remove bushing (3/4") install a short nipple with 90 ell then a horizontal pipe pointed towards the boiler. Install the vents on the antler which would stick up into your newly created box-out in the ceiling.
In any event you want the vents straight up & down and assume that they will have water in them that has to drain back into the steam main.
You could build a antler with tees and add a new Gorton 2 and also reuse the vent you are removing. These 2 together would give you about the right amount of venting.

you probably have the same situation at the other main and may as well open the box. Just for inspection you could get a return air face which is about 14 X 6" to cover your inspection hole. Might not be enough to work thru but there are larger faces you could buy.....this may or not save you from SR work.
Air vents are working devices that should always be repairable and accessible......just as one should never bury an electrical junction box.....it should always be accessible.

ProblemSolver

Don't let the cosmetic's of things over-ride the mechanical operation of your heating system. Cosmetics don't cost you continued addition monthly expenses; but when the mechanics of a system goes awry, it increases the monthly cost and creates discomfort.

jmob77

Right on! It's not so much a cosmetic issue now as a time issue. Hoping to bang it out during the warm months...

ChrisJ

Pull that bushing out and put a close nipple into a 90, move over, put a few tees with Gorton 1s in. For your main I'd do 3 to 5 #1s but some would say it's overkill. I'm running five #1s on a 29' 2" main.

I'd also install a shield of sorts to protect that wiring from possible steam.