two vents on radiator

Please post some pictures of your boiler and the near boiler piping.

I'm a non-pro homeowner, so take what I say with a grain of salt. There should not be any copper in your near boiler piping. Here is an excerpt from my boiler's manual (Burnham Megasteam) that explains why:



Does the return (far right pipe) handle the condensate from all of the radiators or just the ones supplied by the left main in 3935? Your main venting is almost certainly inadequate if the green vent is the only one you have. This should help you understand how to balance your system:

https://heatinghelp.com/assets/documents/Balancing-Steam-Systems-Using-a-Vent-Capacity-Chart-1.pdf

I have a combination of B&J Big Mouth and Gorton #2 vents for my main venting. Works well.

I could be wrong but the water heater vent pipe looks like it was installed backwards. The crimped end is supposed to be on the water heater side, flared end chimney-side. That's to prevent exhaust gases from leaking out.

@random12345 The flue is absolutely going the correct way. If it was backwards the screw head would be on the other side. Please stay on topic. Customer wants a solution to his heating problem. Not to have his boiler nitpicked for issues that ain't related to the problem. If i wanted i could find a problem with every boiler i look at.

can you please take a full view picture of boiler and piping. it helps to have a complete picture to see whats going on

With all due respect @pedmec although your comment may have been well-intended, as far as I know you're not a forum moderator. It's not your job to tell me what I can and cannot comment on. And I disagree with you. When people post pictures on here asking for help solving a problem, it makes no sense not to comment on unrelated issues if those are potentially important. In this case, he has insulation on his mains, but not his near boiler copper piping where the heat loss is substantially higher. Regarding the water heater vent pipe, I don't see how you can tell from such a blurry picture whether or not that thing is attached correctly.

@alanm Another reason I mentioned your water heater venting is because I noticed the water heater's vent pipe appears to connect to the chimney below the boiler's vent pipe. According to NFPA 54 (National Fuel Gas Code), it should be the other way around. Whether or not this is a problem, I can't say. Not trying to make your life more difficult here.



If possible, yes I would consider insulating the near boiler piping. Depending on how long the right main is feeding the 3 rads, the reason those rads are not getting hot may be because you don't have any main vents at the end of that main. Steam follows the path of least resistance. Simply adding more vents to those rads is probably the wrong approach. You might also want to add more main vents to the other main as well. You have a lot of radiators, so your mains are probably pretty long. That document I linked to does an amazing job of describing how to balance steam systems and was written by a pro.

Post some more pictures of that main, the full length of it including the end before it goes into the wall, and as @pedmec said, pictures of your boiler.

Ok. In all those pictures, is the 3-rad main the top or bottom foil-covered pipe? Can you post a picture of the very end of that main in the basement? That would be my choice for where to install a main vent.

The easiest way to start addressing your problem is to increase the venting on the cold radiators, starting with the one on the top of the short main. You probably also have to reduce the venting on the radiators along the long main. That would "hold back'' the steam on the long main until some circulation begins on the shorter one.

Once steam begins condensing in radiators, it draws in more steam. Thus the first to heat continue heating more and those that haven't begun to heat may be completely denied steam.

You may also consider venting the short main, though the improvement may not be worth the work.

As was also mentioned, the piping around the boiler has some deficiencies which further enable the problem, but you should get satisfactory improvement with venting changes.

Switching the vents to a quality domestic product, like Gorton's, may be necessary to balance the system more precisely. Working with home store Chinese vents is often a waste of time, money and energy.

You should also check basic other concerns like boiler run time, etc.

If removing the vent entirely makes the system operate to your liking, and doesn't produce noise, then the problem should be addressable to your satisfaction with increased venting of that third floor radiator or riser.

There are several ways to accomplish this. One would be to pipe a vent on the riser before the radiator. The radiator valve would be replaced with a tee and a straight valve to the radiator off the bull of the tee. The top of the tee's run would take a nipple and a main vent. This is probably too involved, so...

Another vent could be added by drilling and tapping a second vent into the upper part of the radiator, above its present vent, where a hot water bleed would normally be placed. Newer (1930's) radiators usually have an un-drilled boss on the casting for this. This too is involved and may be more than you'd want to tackle.

If you've already tried the biggest vent you can find, like a Gorton D, you can tee two vents together as you illustrate. The drawback of this may be poor condensate handling with some spitting and gurgling, but that would be dependent on steam quality, velocity, and temperatures affecting production of condensate. This may only present on a very cold day in heating a cold radiator. Watch the pitch of the radiator, and make certain it pitches toward the valve. Give it a try. It may work out just fine.

Certainly before you cut into any pipes or drill any holes, get rid of any Chinese vents and try balancing with some real ones. Working with junk parts just wastes time, work and money.

Good luck with your mission.

@alanm There is no subsitute for understanding basic steam principles. Steam follows the path of least resistance. When your boiler fires, steam will rush out towards the single main vent on the left main. Once that main is completely filled and the main vent closes, it will start "searching" for the next path of least resistance. If you put bigger vents on those 3 other rads, the steam still has to push all of the air out of that second main before it can even begin to fill up the risers leading to those rads. In the meantime, some of the steam will be pushing towards the other rads connected to the first main, so you may have to slow the rate of venting on those as well in order to balance the whole system. It's not an ideal situation, and that's why the right approach is to vent the mains as quickly as possible with big vents like Gorton #2 or B&J Big Mouth. That + insulating those copper pipes, should save you money in the long run. A plumber may be able to cut into the second main and add a tee where you can probably DIY screw in some additional main vents and also add onto or replace that single main vent on the first main.

Alan, the Gorton vents are made in sizes 4, 5, 6, C & D. The largest is D. Get one or two big vents on that top radiator, smaller ones on the hot radiators and you should be fine. Then you can play with the rest of the stuff.

I would go with Knauf pipe insulation: https://knaufnorthamerica.com/en-us/products/pipe-insulation. Find your nearest (and cheapest) local distributor and order from them. It is formaldehyde-free. Have it delivered. Or you can go with buyinsulationproducts.com/. Fiberglass is best for steam pipes. Unfortunately, it's also best to wear a respirator/gloves/suit to prevent the fiberglass from going into your lungs and sticking into your skin. At least an N95 dust mask and goggles. Armacell makes a closed-cell elastomeric foam called Armaflex, and their UT SolaFlex is good to 300F. I don't know how well it works, but the advantage is you don't need to deal with the installation headache and it's easier to cut. You can order some and see how it performs. It's such a small job.