Main vent tapped off side of main

david_and_heather

I had a steam pro come to my (new-to-me) house for our first tune up. He said that the main vent connected by a nipple (see first picture) is a bizarre install, but he's not worried because the heat works fine. He said the other one (second picture) is not ideal but OK. The house is comfortable, but all of the radiator vents hiss like crazy on cold days, and I wonder if this is making life more difficult for them. I should say that the system was installed by a regular contributor to HH, so I'm trying not to name names.

I noticed that the pipe on which the first ("bizarre") vent is mounted gets warm, but nowhere near as hot as the main itself. I've also never detected any sign of activity from the vent itself--no sound, no puff of air, no steam, no humidity, no heat. The other one definitely works--it was leaking until the pro tightened it.

This is a 2000 sq ft house with a one-pipe system and a 7yo Burnham gas-fired boiler. The previous owner had it serviced annually by the installer until it was sold.

Steamhead

Not ideal, but we've done this too. As long as it's working, i.e. the vents vent air and don't leak steam or water, you should be OK.

Where are you located?

david_and_heather

Located in Maplewood, NJ. It doesn't seem like the one on the nipple vents air, although I'm not sure. I have not noticed any sounds or air coming from it at any stage in the cycle. On the other hand, maybe it's working very well and is therefore just silent. Is there a way to check for sure?

Gsmith

Both should work reasonably well, the nipple and pipes leading to the vents look to be 3/4", plenty of capacity. The vents could (underline "could") be clogged, especially if your boiler is or was at some time operating at too high a pressure level.
What is the pressuretrol set to?

Do you have a low pressure gage near the pressuretrol, and if so, how much pressure does it read at the end of a boiler run cycle?

You can informally test those vents by lightly tapping on them when the boiler is cool and not running, they should rattle slightly when cool.

When the boiler runs and the steam mains get hot near the vents, if you tap the vents slightly they will not rattle but will feel and sound "solid" (the mechanism inside is closed).

You can test the vents more directly by removing them from the pipes (after turning off the boiler at the electrical switch if it has one or if not, turning your thermostat down as far as it will go while you are checking the vents). Those Gorton vents should be easy to blow air through when removed from the pipe. And if they don't leak steam when attached and are easy to pass air through when removed from the pipe they are pretty sure to work. Don't forget to turn the boiler back on or the thermostat up after you put the vents back.

Jamie Hall

I would add to @Gary Smith's comment that vents -- including Gortons -- even new ones -- have been known to fail. Try his test, but be careful and make sure the boiler is off!

david_and_heather

@Gary Smith, sorry, stupid newbie question: this red switch is the one you're talking about, right? And if I flip it, the only thing I have to do to turn the heat back on is flip it the other way? I don't have to re-light the pilot or anything?

Gsmith

I don't know about the pilot. I have a millivolt system with no on/off switch. maybe others could chime in.

Fred

A standing pilot will not be affected by turning off the power off.

JeffM

From your description, the first ('bizarre") vent may not be doing its job. If the section of pipe it sits on doesn't get as hot as the main, it's probably not venting much or at all. Does this section of main perhaps take longer to heat up than the one served by the other vent? If so, that's another hint that the first vent may not be working.

EBEBRATT-Ed

The vent installation is not ideal but many old steam systems aren't piped "TEXTBOOK" and work fine much to the consternation of many HH members..

The best way to tell if the vents are working (without a lot of fiddling around) is to turn the boiler off for a while so the steam piping is not hot (lukewarm is fine).
Turn it back on and make the thermostat call for heat, turn the stat up hig so it will stay running. Hold your hand on the supply pipe leaving the boiler. When your hand starts to sizzle, start timing with a watch. See how long it takes for the steam main(s) to get hot at the vent location. As hot as the boiler supply got Not the vent nipple but the steam mains itself.

Don't get burnt and restore the thermostat to it's normal setting

Then report back on the times.

Jamie Hall

EBEBRATT-Ed said:

The vent installation is not ideal but many old steam systems aren't piped "TEXTBOOK" and work fine much to the consternation of many HH members..

....

That is so true -- as I've said before, it is really amazing how forgiving steam systems are.

MilanD

The main vent that you say is sitting on a pipe which doesn't get hot is not venting. If pipe is luke warm while the main is hot, vent is not working, plain and simple. It's a dead leg and thus it's not hot. If the vent works, that pipe to it would get as hot as the main. Also, that first picture has a bushing on the horizontal run, which will do 2 things: hold the water and any debris, then get that water and debris pushed up into the vent, blocking it. Get a 90 on there that's the same size as the pipe, and then pipe it up to a correct size pipe to receive the vent. It will look like a funnel when piped correctly.

Hissing radiators can be from that closed main vent, as all radiators now take the main venting role. Also, do you know if your boiler is sized correctly? If it's oversized, workaround for the previous owner may have been jacking up the pressure. This too will create more force on the vents that work. You said it was installed by a pro from here, so probably not. However, 7 years in, pigtail pipe may be blocked and pressure may be high, or, also likely, as pressuretrols are known to be horribly inaccurate, ptrol may be out of calibration. Worth checking out.

EBEBRATT-Ed

@Jamie Hall yeah, If you get the job 90% right it will usually work. Usually
And then there are times when the other 10% just kills ya.

david_and_heather

@MilanD, I think that the hissing comes from the radiators that are served by that main. The second main only serves an addition. I was about to replace all those vents! The pro who serviced the boiler a couple weeks back did take apart and check the pigtail, and he said that it was clear. When I have him back for something else, I'll have him replace that section of pipe with a proper "T."

david_and_heather

An update on this: I let the system get cold on a 55F night. Cranked it up with a stopwatch in hand. After 45 seconds, the supply pipe at the boiler was too hot to touch. By 9 minutes, the pipe right BEFORE and AFTER the "bizarre" vent was too hot to touch--but the arm the vent is on was cold.

After about 40 minutes, the arm was hot except for the 3" before the vent. The vent itself was nearly cold.

Correct me if I'm wrong--I take from this that the arm is able to get steam into it, and that the vent itself is totally clogged. Therefore, if I replaced the vent, the system should at least work a bit better. Is that right?

MilanD

david_and_heather said:

An update on this: I let the system get cold on a 55F night. Cranked it up with a stopwatch in hand. After 45 seconds, the supply pipe at the boiler was too hot to touch. By 9 minutes, the pipe right BEFORE and AFTER the "bizarre" vent was too hot to touch--but the arm the vent is on was cold.

After about 40 minutes, the arm was hot except for the 3" before the vent. The vent itself was nearly cold.

Correct me if I'm wrong--I take from this that the arm is able to get steam into it, and that the vent itself is totally clogged. Therefore, if I replaced the vent, the system should at least work a bit better. Is that right?

Vent's not working... try tapping on it - looks like it's a new vent. Sometimes some dirt may get into it and block it, or from sitting on a truck and riding around hitting pot-holes for months. Tap on it with some kind of a tool, and if that doesn't change operation, take it off and see if it'll rattle and if you can blow air through it - there is a float inside this thing, it may just need to be jostled loos a bit.

Fred

I would say that vent is definitely stuck closed. It probably needs to be taken off and cleaned or replaced.

nicholas bonham-carter

Noisy radiator vents always signal to me a lack of adequate main venting.
You may find the main vent to be open, and yet not working as a result of high pressure pushing up the water level in the wet return enough to submerge the tapping. The water in the wet returns rises up 1.75 inches more for every ounce of pressure, and that may be enough to waterlog the main vent.
Measure the difference in height between the tapping, and the waterline of the boiler, and post it here.
A good low pressure gauge (0-3 psi.) would show what your pressure really is.--NBC

gennady

The air vent in 1st photo is a radiator vent, it is too small. switch it to Gorton 1 or 2.