Basic question - replacing main vents

WillNH

Hi all,

First off I want to thank everyone for this great community! I've already learned a ton from reading posts on this forum and Dan Holohan's We Got Steam Heat. I just started making my way through The Art of Steam Heating Revisited, but in the meantime I already identified a few problems that I want to fix ASAP, so I wanted to check here to make sure I'm not being too much of a knucklehead.

Quick background, last spring my wife and I bought a single family detached house with 1-pipe steam heat, so this is our first winter. When we first tried turning the heat on nothing happened, so our oil company sent a technician who pointed out that the sight glass was completely full of water and proceeded to drain a few five gallon buckets worth of water. Things have been running since then, but our upstairs has been too hot, downstairs too cold, and oil bill too high. The radiators also hiss quite loudly when heating, not all at the same time, but more like taking turns.

The biggest obvious issue I've found is that the main vents are clogged. I took them off and tried blowing in them, one had a lot of resistance, and the other seemed completely blocked. There are two mains, one is about 60 feet (with 5 radiators) to the vent, the other is about 40 feet (with 4 radiators). The mains are all insulated, and I haven't checked the size of the pipe yet. The vents are Vent Rite #35, which I think would be too small even if they were working properly. I am planning on replacing both with Barnes & Jones Big Mouth vents, but I am wondering if I need a smaller vent on the shorter main to balance the system?

The other big issues I've found is that the radiators all have Dole 1A vents, which are who knows how old. I removed and blew into them, and some seem okay but some have really high resistance or are completely blocked. So I'm planning on replacing with Vent-Rite #1s.

Does this all seem like a reasonable plan? Or should I do more homework with The Lost Art of Steam Heating Revisited before I start changing things?

Thanks,

Will

JUGHNE

I would go with the Big Mouth on each. It is right for the 40' and the 60' could use even a little more. If your old main vents are working, you could add those along with the BM on the 60'.
How large is the existing main vent tap into the steam pipe?
There could be a bottle neck at that point.

The thought is to not balance the main vents as much as to balance the individual rad vents.
I would not do anything with the rad vents until the main venting was done.

JUGHNE

But first, check the pigtail for blockage and where is the pressure control set at?
Do you know why the system overfilled?
Pictures of boiler piping floor to ceiling are good.

WillNH

Thanks!

Both main vents are on pipes that are about 1 inch outer diameter. You can see one in one of the attached pics.

Checking the pigtail is on my to-do list. The pressuretrol is set as low as it will go, 0.5 psi with 1 psi differential.

Not sure why it overfilled. The water level crept up again in the first week or so so I drained it back down to the normal level, but it's been stable in the three months since.

Here are a couple pics, hopefully they show the important bits.

JUGHNE

You have two steam mains going horizontally from the boiler header which has 2 steam risers going up. Are they tied together above the header riser pipes?
If so that is pretty unique....don't know the ramifications of that situation.

Your vents seem to be on 3/4" piping, 3/4" ID and about 1" OD.

Different approach with the pipe insulation wrap though.
At first glance it seemed a test of dryer venting flex.

WillNH

I squeezed the insulation wrap between the two mains, and it doesn't feel like there's anything there, so I don't think they're connected above the header.

gfrbrookline

As @JUGHNE said go with the Big Mouths, I would use 2 on the 60' main. You also can't go wrong with the Vent-rite #1's for the rad's. The are practically silent and easily adjusted.

WillNH

Thanks! What would be the easiest way to add a second vent to the main?

WillNH

Trying to answer my own question. The vent is currently on about 8 inches of 3/4" piping going vertically from the main. Can I just remove the vent, add a tee, horizontal nipple and elbow, and have one vent on the tee and one on the elbow? Is 3/4" pipe big enough for two big mouths? Or maybe a big mouth and a smaller vent?

JUGHNE

Yes, antler type manifold.
3/4" should be enough for 2 BM, IMO.

amitjm1980

I'm no expert, just a homeowner who did a lot of research but I did the math on my setup (two mains/dry returns, both with about 25' of 2.5" main pipe and 25' of 2" for the dry return) and I could have went with something smaller but I used a Big Mouth on each and couldn't be happier. I also did the test where I timed how quick the steam reached the main vent locations without the vents attached and verified it reached the same time with the vents attached. You can't do any better than that. In my setup, the main vents are at the ends of the dry returns before transition to the vertical wet return. For the price, they seem to be built way better than anything else out there.......and they made a HUGE difference in how quickly my system heats up. They don't like water so either raise them up or offset them to the left or right of the main just in case. This is a photo of mine. I've since turned the offset 180 degrees after the helpful folks on this forum noticed that they were sloped the wrong way and could fill with water instead of draining back down the wet return.

gfrbrookline

Yes, just rotate the elbow 180 degrees so it can drain and add a T in the middle for your 2nd Big Mouth.

gfrbrookline

You want a 3/4 90, close nipple, 3/4 T, close nipple, 3/4 90 or a T with a plug.

WillNH

@amitjm1980 thanks! The big mouths should arrive today, I can't wait to put them on!

@gfrbrookline thanks for the clarification, that sounds doable.

gfrbrookline

Building an antler is very easy if you have 2 pipe wrenches. Make sure to wrap the threads with tape or use dope. Only wrap the spud in the Big Mouth, no need to do anything the the union where the head mates with the spud. You need a 5/8" allen wrench for the Big Mouths.

amitjm1980

@gfrbrookline good point on the wrench, the 5/8" allen is hard to find, you may want to order it on Amazon....my local home Depot didn't even have it.

JUGHNE

Take your tailpiece to the hardware store. Find a punch that has the correct shape and just fits where the 5/8 allen would go.
Use a wrench on the punch.
Or if a "Cat's Claw" is the right size, that is a tool you might use elsewere, again the wrench on the shaft.

Or a bolt head that is that size, put 2 nuts on the bolt and jam them together. Use a wrench on the top nut.

WillNH

Thanks all for the detailed instructions! Very useful for someone like me who isn't very handy... I installed the two big mouths (used the trick with a 7/16 bolt head), and replaced all the radiator vents with vent rite 1s. Wow! What a difference! I'm able to keep the second floor cooler and the first floor warmer. Most importantly my wife is very happy.

I haven't built the antler to add the second vent to the longer main yet, but will do that soon.

I am concerned about the pigtail. I was planning on checking to see if it was blocked and to clean it, but I noticed that it is coming straight out of the boiler horizontally, and is low enough that the normal water level is above the bottom of the loop. If the water goes to the top of the sight glass, the whole pigtail would be submerged. That's not right, right? Should I just replace it with a 90 pigtail, or do I need to raise it more somehow? See attached photos.

Also thanks again for all the help! It's really awesome how much better my system is running already.

ethicalpaul

I think you're fine. You could replace it with a nice new brass "angle" kind of pigtail. That would get your controls a little higher, but I wouldn't worry about it.

I don't like the way they put the power switch stuff right in front of your skim port!

amitjm1980

I think you are good, mine is exactly the same. If the water level is higher than the pigtail connection level, I don't think the pigtail can fill any more with water. Half the loop should already be full of water either from the initial installation or just vapor collecting over time.
The water would need to displace the remaining air in the pigtail (the air between the existing water in the pigtail and the pressuretrol), but it can't because everything is sealed so there's no place for the air to go. This is a normal set up. When you skim the boiler, the water level will always be at or above the level of the pigtail inlet.

Fred

Looks fine to me. I agree with @ethicalpaul, that conduit should be moved to one side or the other of the skim port. It's not critical but, sooner or later you will replace some piping and need to skim the boiler.

JUGHNE

That conduit could enter the side of the box by using an "SLB" or "LB" fitting with a "chase" nipple to hole it in the box.
The easiest time to get that plug out is now.
Could be a spring project. Get an 8 point socket for square plugs that is a good fit. You can rent an impact drill for removal.
After applying PB blaster or such several times.

WillNH

Thanks for all the responses!
I finally checked the pigtail, and it is indeed completely blocked. A little thick, black liquid dripped out the end when I removed the pressure gauge, and the smell reminded me of the grease I used to use when working on my bicycle... I ordered the angle pigtail that @ethicalpaul recommended and will replace it later this week.
@JUGHNE thanks for the detailed recommendation. I'm thinking that's too ambitious a project for me though.

ethicalpaul

You can do anything with the whole summer coming! 😎