Possible venting issue?

bkemp

I have a 2 pipe steam boiler system in a 101 year old house that we just purchased in August, so this is our first heating season. The house is 2 stories with the boiler in the basement. When the system was fired up in early November the technician didn't know much about steam units, but through some phone calls with a colleague of his he as able to help me get it started. We have always had an issue getting the rad in the kitchen to work. I can remember one morning coming into the kitchen and it was working, other than that the only other time it worked was when we turned off all the other rads on the line before it and then it warmed up. Within the last couple weeks we have also had issues with a rad in an upstairs bathroom and bedroom. The bathroom rad worked great until just a couple weeks ago. I had "the steam guy" from the company we used to start up the boiler come and he spent several hours trying to troubleshoot and really got nowhere. So another tech came out and said that I have a radiator venting issue. There are a couple different types of Hoffman vents throughout my system. The kitchen rad has no vent, the bathroom has an adjustable one, and the bedroom has a non-adjustable one. In reading the book "We Got Steam Heat" and this forum I learned that we should have main vents, which I don't believe I have any (maybe one if the Hoffman main vent vacuum valve is a vent and is operating?). I also read in the book that 2 pipe systems don't require a rad vent. I know I have an insulation issue that I'm working to resolve. We do have some water hammer happening, it has increased slightly but it's not quite as violent as some I've read on here. So here are my questions and where I could really use some direction...
1. I found a plug at an elbow near the farthest point from the boiler on the main line...should I install main vents there? If so what's the rule of thumb (1 vent per 20ft of pipe, etc?).
2. In installing main vents do they have to be spaced out or can they all be placed together? For example...if I have 100 feet of pipe can I put 5 vents in that one spot?
3. Should my radiators have steam vents?
4. Should my return line have vents?
5. What's the best main vent for my application?
6. What are the odds that Hoffman main vent vacuum valve is working and how could I test it?
7. How thick of insulation is needed when covering the steam pipes?

Here are some pics of my system. Any insight is greatly appreciated! I am so thankful this forum and the other resources are available...thank you!

Steamhead

Looks like you have a Webster Vapor system. This was the Cadillac of heating in its day and is still one of the best out there.

That Hoffman #76 vent on top of the air trap is, or should be, the only air vent in the system. But it's too small to work properly- replace it with a Gorton #2.

The radiators should not have air vents on them. The air goes into the dry (overhead) return lines and is vented out of the air trap. If replacing the vent with the Gorton doesn't help, you probably have bad traps on some radiators. We can still get parts for Webster traps.

There should also be some sort of venting device at the end of each steam main, which may be a radiator trap or a "float and thermostatic" trap. How about taking pictures of the ends of the steam mains, as well as a few radiators?

Also, where are you located?

bkemp

I will order the Gorton #2 right away. I will get some pics of the radiators. From my memory, I'm not in front of the system currently, the mains form a loop in the basement. The pic of the plug I posted earlier is about the furthest point from the boiler. There are traps on most if not all the radiators, at least the tech told me they were traps. We are in North East Indiana right outside of Fort Wayne...so if you know of any good steam folks in this area please let me know! Thank you for your time and insight and I'll get those pics soon.

vaporvac

@Steamhead , does replacing a system vauum vent mean it can no long work as a vacuum system? If so, is there an alternative vent?

bkemp

Here are some radiators... I'll get the other pics in a little bit.

Steamhead

That's gotta be a system that was originally installed as a one-pipe system and then Websterized. We've seen a few of these Websterizations. The size and placement of the radiator valves is a dead giveaway. It also may explain the air vents on some radiators.

What did you find at the ends of the steam mains?

Steamhead

vaporvac said:

@Steamhead , does replacing a system vauum vent mean it can no long work as a vacuum system? If so, is there an alternative vent?

This kind of naturally induced vacuum doesn't work well on oil or gas firing. It was great on coal firing. But on oil or gas, it often goes into vacuum before all the air is out, and the expanding air kills the steam circulation.

But with a small vacuum pump hooked up to that single air vent, like the Dunham Differential "DH" system used in the late 1920s, you could produce steam at lower temperatures and have control over it as well.

bkemp

Here's what I found at the end of the main line...again it's in a loop. I took a picture coming out of the boiler and then the rest are from pipe off the right side of the boiler all the way across the back. It does go through a wall to complete the loop.

Also...there is a little unfinished crawl space that I got to looking around in and found the last 2 pictures. I'm pretty sure it's a main or 2 mains that get connected by the smaller vertical piping with what looks like a trap to me connecting the two pipes?

Thanks again for any help!!

Steamhead

Right, those traps vent the mains into the dry return. Those should vent quickly to give you the fastest possible steam distribution.

How long are your steam mains, and what pipe size are they?

bkemp

We've got just about 115' of main pipe. I don't know the pipe sizes, but it looks like the pipe out of the boiler (riser pipe?) is the largest, then the header pipe is the middle size and going through the crawl space and back into the middle size pipe is a smaller pipe. I posted pics of those with a tape measure.

The last 2 pics are of the turn the pipes take to come back out of the crawl space into those traps to the dry return.

Steamhead

First pic is 1-1/4" inside diameter.
2nd is 2-inch.
3rd looks like 4-inch.

So I'm assuming that there are two 2-inch pipes that come off the 4-inch pipe at the boiler, then loop around to the crawlspace where the crossover traps are. How long are the pipes between the boiler and each of the crossover traps, and is this all 2" pipe?

And what happens between the location of the crossover traps and the last two pics you posted? Do the ends of the steam mains tee together before dropping to the wet return (the one below the boiler's water line)?

bkemp

This question will show my lack of knowledge...how do I know where the water line is in the boiler?

Steamhead

bkemp said:

This question will show my lack of knowledge...how do I know where the water line is in the boiler?

It's where the water stands in the sight glass- the glass tube that shows the water level. Usually this is about at the halfway point or slightly below.

bkemp

There is 41.5ft of 2" pipe between the boiler and the crossover traps in the crawl space. There is 6ft of 1 1/4" coming off the 2" pipe into the crossover traps. I'm not sure if I have this concept correct, but from the crossover traps a 1 1/4" pipe comes back toward the boiler, drops down below the water line and tees into another 1 1/4" pipe that runs back to the bottom backside of the boiler. The pic with the green bucket is of that pipe.

I tried to get shots of the pipes from the top of the boiler and the backside of the boiler.

There is just a straights shot from where the 2" pipe ends and the 1 1/4" pipe begins and heads into the crossover traps. Then like I said above it runs back toward the boiler tees at the bottom of the crawl space and heads to the boiler...there is a pic of that though not a good one.

Steamhead

I think I see what may be part of the problem.

After the crossover traps, the 1-1/4" pipes (which are return lines beginning at the tees that go to the traps) drop to the bottom of the crawl space, tee together, and from there a single pipe drops to near the floor level and heads back to the boiler. This single pipe tees into the pipe coming down from the vent trap, and then rises to the Hartford Loop at the boiler.

But if the bottom of the crawlspace is above the boiler's waterline, there will be no water standing in the tee where the two return lines connect. This lack of a "water seal" can allow steam to pass from the end of one main to the end of the other.

So here's what I'd do after installing the Gorton vent:

Start the boiler, wait for the steam to start moving into the 4-inch riser, and go back to the crawlspace. Check to see how long it takes for the steam to get to the crossover traps- the steam should go up the 1/2" pipes to the traps but not come out the bottom into the dry return. If no steam goes up to the traps, or the steam comes out the bottoms of the traps, the traps have failed. If the traps appear to be working but the steam takes more than about 2 minutes or so to get to them, they are not venting air quickly enough.

Then check to see if the steam travels down one of the returns to the tee in the crawlspace and up the other return. If so, there is no water seal in that tee.

If the crossover traps are not working, you can either rebuild or replace them. These are Webster #02H traps and parts, as I said, are available. However, even if they are working but the steam takes more than 2 minutes or so to arrive, I would replace them with Barnes & Jones #122A or MEPCO #1E traps, since these will vent air much faster than the 02H units. You can hang onto the 02H traps to use for parts if needed.

Now as to that tee in the return line- if, after the crossover traps are working properly, the steam goes down into the tee and up the other side, and either bangs or closes the crossover trap on the other main before the steam arrives from that main, this tee will need to be repiped. Basically you would need to drop both returns to the level of the single return line near the floor and tee them there. This way, some water would stand in the pipes above the tee and the steam could not get past the tee. But you may not need to do this if the steam arrives at both crossover traps at about the same time.

I know this is a lot to digest, but once everything is working as it should, the system will run much better and use less gas.

Fort Wayne would be a pretty good place for a steam specialist. I've consulted there in the past. If any contractors in that area are reading this, please speak up! Better yet, get a Find a Contractor ad on this site. It's the most effective way to get into the steam market.

bkemp

I will install the Gorton #2 and then check the returns. Do you think I need more venting on the main? Also, should I remove all he steam vents from the rads and plug those holes?