Steam radiator air vents

David Nadle

Scot,

Your question mighta got lost in the middle there. You need to get a gauge that measures in oz/in^2. You're probably operating at .2 psi or so and an analog gauge is usually not that accurate near its extremes.

mark ransley

Steam radiator air vents

I use 4-5-6-c-d Gorton air vents on radiators, a few are to hot with 4s, what fixed vent that a tenant cannot tamper with that will close sooner to give less heat can I buy.

Steamhead (in transit)

What main vents

are you using? This has a lot to do with how you vent radiators.....

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mark ransley

I use gorton but this apt is right above the boiler

David Nadle

Why not use a TRV? Danfoss makes a model that is supposed to be tamper-resistant.

er_2

dd

U are a rocket scientist sh.

Steamhead (in transit)

How

did you size the Gorton main vents?

This is important because the mains should vent completely BEFORE steam rises to the rads, even the rads close to the boiler.

Measure the length and diameter of your steam mains and tell us what vents are on them. We can tell you what you need.

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nicholas bonham-carter

steam economy

sounds like our situation before fixing all our steam problems.buy dan's books on steam on this site so you can do these improvements yourself.
we use all the same hoffman vent on the 60 rads,and chose main air vents sized to fill the mains at the same speed.
we dropped the pressure to 8-12 OUNCES [if you can see pressure on the 30 psi gauge,it's too high] and money is being wasted in a big way.
we insulated all the steam mains so the apt. above the boiler would not get so hot,and for efficiency.
these improvements + a new boiler will reduce our consumption about 15%. this is especially true in the shoulder seasons so now is the time to correct any problems.
i suspect you have the same problems we did, and will have the same happy result we did.as always a steam-knowlegable pro can guide you and help you do much yourself.good luck--nbc

Phil_17

steam vent mains

Hi everyone, so i was finally able to take out my rusted main, looks like a hoffman valve. I replaced it with a 1/2 inch gorton main vent valve. how do i know if this is the right size? The plumbing store told me they come in 1 size and thats it, but im reading on this forum that you have to size your vents properly.
WHat happens if you dont size up properly?

Brad White_203

What happens? What happens???

Undersizing a vent is like undersizing anything, cars, underwear, houses... no room to breathe! Your system will take that much longer to heat. You may be OK though, as we shall see.

The plumbing store is good for carrying Gorton vents at all, but as far as saying they come in only one size? Maybe they only carry that one size is what he is telling you.

"When you only have a hammer, every problem becomes a nail."

Gortons come in seven sizes, #2 being the largest main vent, #1 as the smallest main vent, then radiator vents sizes D, C, 6, 5, 4, each venting less and less but which are applied so that those closest to the boiler vent less, further vent more, such that all the mains come to temperature at about the same time.


Now, a 1/2" vent means little except for the stem size. A Gorton #1 has a 3/4" male pipe thread stem but also accepts inside this a 1/2" male nipple so you can connect it to either size pipe.

The #1 is about the size of a large pocket watch or a small hockey puck. Do not confuse the two! One good slap-shot and you are out of time.

A Gorton #2 has a 1/2" male stem and the body is about the size of one of those black and white pastries we used to get as kids, like last week. You know, about 5 inches across it seems. Maybe this is what you have?

The right way to size a main vent is varied but similar in principle. What I do is first figure out how much volume is in the pipe I wish to vent freely of air and how quickly.

For example, for 2" pipe, every 43 feet of it contains 1 cubic foot. If I have a 2" main about that long and I want to vent it at say two ounces of pressure in about two minutes, I would select a vent that passes 0.50 CFM (cubic feet per minute) at that pressure.

A Gorton #1 would do that in that amount of time. A Gorton #2 would do that at the same pressure in about a third of the time.

Of course, your main size and lengths vary.

jackie_3

Thanks Brad.

Thanks for the awesome clarification. With respect to sizing, then wouldnt the bigger the better?
Should I order a Gorton #1 now from Pex.

Brad White_203

When size matters..

Thanks for the kind words

Bigger is not necessarily better in some cases. Venting too fast to one side might not allow steam to pass into other branches because excessive venting practically can draw a vacuum. One of those phenomena that steam practitioners talk about over beer. By the end of the night, that vacuum becomes the Black Hole sucking in the entire universe...

At the same time, if it is a dead-end vent, I say, why not? Fill it with steam and let the radiators take their fill. Others may have differing opinions of course. I see no harm.

A Gorton #1, just to be clear, has about 1/3 the venting capacity of a Gorton #2, so buy what you really need.

Dry Steam

Sizing

Brad, When sizing your mains do you measure from your header to your main vent? Or where the main stops and t's off into two distinct dry returns? Speaking of my own it starts at 3" main then t's into two 2" returns at the end of whcich is a hoffman #75 on each. Clarification would be most helpful.

Brad White_203

Personally, in a one-pipe system

I would take each dead-end main as it's own entity, from the boiler if that is where it starts. The near-boiler steam piping air also has to be vented, so take that into account of course.

In your case, similarly, the goal is to get all of the air out ahead of the steam. So in your case, ideally, I would vent the 3" main separately if I could (thinking "wholesale air removal").

Absent that, there is nothing wrong that I can see with using your 2" main vents to vent that 3" section.

If the 2" runs are equal and come off the 3" at the same time, I would apportion the volume of the 3" section equally. If the 2" sections differ, say 60%/40%, I would apportion their venting of the 3" accordingly.

Now, I prefer to have vents at the ends of my mains with another at the end of the dry return, but some prefer to use their dry returns to vent the entire upstream run.

You can vent the entire run using the dry return so long as there is not a pocket where condensate can collect and block the venting,("Accidental Wet Return", which should be fixed regardless).

I see nothing wrong with doing this so long as the dry return, as a pipe size, represents enough venting capacity in itself. Usually this is a 1" pipe at least so that is plenty for a typical residential steam system, especially if one side of the house only.

No magic about it and not necessarily the only way. I am sure others approach this differently.

Dry Steam

I have a t in the 3" main two feet before the two returns split off. This was installed when the system was ( 1930's ) and is set at a 45 angle. Obviously for an additional rad at some point. I could probably reduce and raise out of that with a 3/4 pipe and install a main vent there??? It does take several minutes(5-6) for the existing vents to close. The system is very quiet, no whistling and seems to be even balanced. Should I mess with it or try to improve it? Not that I have any more knowledge than deadmen, however the boiler is different.

Dry Steam

Also the two 2" returns are evenly measured. Would another Hoffman 75 work on the 3" or something different. And thank you for your assistance it is greatly appreciated.

P.S. I love my steam heat and wouldn't trade it for anything.

Brad White_203

Hoffman

Hoffman 75's are to me, slow vents, less than half the capacity of a Gorton #2. The lengths per size and timing you expect is what is needed. Nothing meant against Hoffmans, just capacity to capacity.

Your 5 to 6 minutes is about twice what I have had others give as an ideal, so doubling the venting could not hurt that I can see. I would also hope others would chime in, but three minutes or less seems fair.

I have balanced a few systems in this past year to about 90 seconds and it took more venting than I initially thought, (by eye). In the end, the charts did not lie. By "Charts" I mean Gerry Gill and Mike Pajek's very useful and kind, "Balancing Steam Systems" e-booklet, available through the online store.

I suggest that you treat yourself and others in so doing.

Glad you love steam! I long to have one, given that I have sinned in the past with ill and ignorant treatment. Restoring them with relatively simple devices is a Mitzvah.

nicholas bonham-carter

adjustable main air vents?

i would like to see them make adjustable "big capacity" air vents with a built in thermometer.balancing the mains would no longer be such guesswork-just keep adjusting them until they all get equally hot at the same time [assuming they are at the end of the dry return].
in the absence of that, what about putting a small gate valve between vent and return so it's capacity could be tweeked?
of course a little more cost would be involved; but what of the cost of having to buy extra vents of different sizes to experiment with?--nbc

Dry Steam

Curious

So today I bought and installed a low presure gauge, 0-5 psi instead of my 0-15, and fire the boiler in hopes of fine tuning the system.. Its a one pipe wood fired with two risers one three, one two inch to a dropped 4" header. One 3" take off that runs 65' to a tee where it splits to two 2" mains and returns to the boiler room and drops after the two main vents. Hoffman 75's. System satisfied the thermostat before any pressure was indicated on the new 0-5psi gauge. It took eleven minutes for steam from header to vents.

Is the system running as efficient as can be or should I add main vents to system? I have posted here before in another thread the other day and Brad White answered some questions of mine. I thought I would change the psi guage out to determine what my system pressure is, but that didn't work the way I planned. Any thoughts? Any more info needed? I mean I get heat when I call for it, and its a quiet system. Ohh one more thing... the main vents cycled 4 times?????? Can't figure that one out.

Also posted in a thread under presure gauge!!

Dry Steam

Bump