Steam newbie on path to enlightenment

Unknown

You've grasped it well.

You have an old Dunham Vapor system. You can't run that at a pound if you leave it gravity, and I WOULD leave it gravity.

The air vent is the place in the system that steam pushes air to when the system starts. Picture everything rushing down the mains and back down the returns, at that vent.

The other thing is a return trap, or alternating reciever, or one of many other names.

It pushes water back into the boiler with steam and air pressure, if the steam pressure built up too high.

If you have the Lost Art of Steam Heating, look at pages 270 (#5), 252 (5), and the picture on 230. Do you have the piping arrangement on page 230? If so, it's an oldie. I'm thinking you don't, and it's a little newer.

Noel

Steve_35

I'm a steam newbie looking for some experience before I shoot myself in the foot. We've pretty much been handed a larger (350K input) steam job and I need to educate myself. I picked up most of Dan's stuff on steam and have been going through it.

I checked the connected load using Dan's EDR. It's too cool to find this old stuff in a book with all the info you need. In any case the current boiler is properly sized for the load.

I'm trying to wrap my mind around the piping. This is a two pipe gravity system. A question here. I think the term wet return refers to returns that are full of water when the system is off and dry returns would be pretty much empty of water when the system is off and at ambient temperature. Is that right?

Here's where I want to clarify something. It's about 87" from the ceiling to the mid point of the sight glass and 24" from the floor to the same point on the sight glass. So any returns that are at 87" down from the ceiling or less are going to be wet, right? And we want to maintain an "A" dimension of at least 28" from the water line to the bottom of any horizontal dry return if we're using 1# steam pressure, right? BTW, I have all these "rights" in here because I'm looking for confirmation that I understand this.

There are a couple of short horizontal runs that seem to me to be too low here. One measures 80" down and the other 84" down. Now the boiler water line is 87" down. Is this an existing problem?

I'm still a ways from finishing "The Lost Art Of Steam Heating" so please bear with me. Most of the radiators have a valve/trap on the return side. It's marked "Dunham #1A Heating Device". I assume this is a device to allow the water into the return but not the steam.

There are also a couple of things in the basement. Both are made by Dunham. One is a return trap type #3A and the other is an air eliminator type #220. I don't want to assume what these are. Could someone enlighten me?

Thanks for any help you can offer.

Steamhead

You have a Dunham Vapor system!

This was one of the nicest systems of its kind. Once you read the fundamental chapters of "The Lost Art of Steam Heating", go straight to chapter 15. You'll find a very good description of how this grand old system works.

The Air Eliminator is the only air vent in this system. It vents air from the dry (above the waterline, you had it backwards- anything higher than 87 inches from the ceiling or 24 inches from the floor will be dry when the boiler is off) return. The steam mains are probably vented into the dry return through standard radiator traps like your 1A units. The 1A traps on the radiators work just like you thought- they pass air and water but close against steam. The air from the radiators goes thru the trap, into the dry return, and vents thru the Air Eliminator.

The Return Trap is there to help the water get back into the boiler if the pressure gets too high. This is needed since the drip from the dry return is a "B" dimension rather than an "A" dimension. If this unit is not working, Tunstall (www.tunstall-inc.com) can rebuild it. If you use a Vaporstat on the boiler instead of a Pressuretrol, the Return Trap is not really needed... but can be kept as a backup.

How about some pics?

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Steve_35

Pictures

Here are a couple of shots.

Unknown

Wow

Cast Iron Hams! WAY cool!!! Don't pipe the new boiler quite the same way........

I just dug out an old Webster system, in pictures. I want to bore you with them.

The olderest vent trap I've seen is the one above, in the other post. Yours is newer.

Pick up a clear, 5/8" or so hose, and put a garden hose female end on one end. Use it on the boiler drain, and hung up above the highest main pipes, with an open end. Open the drain. See pics....

As you build vacuum or pressure, the water in the hose moves up and down. Just like the water in the returns. You can see how high the water in the returns is at any time, with this tool. You can use it to see vacuum in the boiler, and pressure in the boiler. 8 ounces is a 1/2 pound is 14 inches water column. Use this to see the water rise up at that return trap. Use it to see how much water is stacked behind those check valves. (you need them to work, if you keep the reciever).

Noel

Boilerpro_3

Boy, that's a....

really bad pipng job! You're going to save them a fortune and give them comfort they never knew they had if you get the new one installed right.

Boilerpro

Unknown

Hey Boilerpro...

Did our rep contact you?

Noel

Boilerpro_3

Nope, What's Up?

Steamhead

\"Rust\" photo

That rusty pipe coming out of the floor may be the wet return line. If so, I'll bet it's leaking. Pipe the new one slightly above the floor if you can.

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Unknown

I'll call you

Monday. Any special time?

Boilerpro_3

About 9:30 Central Time

Hope to hear from you then!

Boilerpro

Steve_35

Piping questions

Remember this is a steam newbie here. From reading Dan's book it looks like they should have left the lines off the boiler at 3" and manifolded them together using 3" as well. They do have at least 24" above the water line before the horizontal steam line. Do you see something else here or am I totally off base?

I think I've got the pressure relationship as we do a lot of water boilers. This is sort of an extension of that but trying to sort out just what's happening inside the system is taking me a while.

I like the idea of the clear tube to see just what's going on inside.

What about the dry/wet return question in my original post? The water line is 87" down from the ceiling. There are a couple of horizontal dry returns at 80" and 84" down respectively. Isn't that a potential problem if they're not at least 28" higher than the water line or at most 59" down from the ceiling?

Steve_35

pressure

> You have an old Dunham

> Vapor system. You can't run that at a pound if

> you leave it gravity, and I WOULD leave it

> gravity.


There's a pressuretrol on it now set for about 3#. This thing is really a mess. We're there plumbing a new bath and two new kitchens. Their indirect quit working. While my son was fixing that he took a good look at the boiler. The far end of all the burners is lying on something that looks sort of like white sand. The support for them is rotted away and it looks like a couple of the burnres may have holes in the end. The steel support for the casting has holes rusted through it. He checked the CO right off (good boy) and it was surprisingly low. Less than 50ppm air free.

I haven't wanted to touch this thing any more than necessary because the bottom of it looks so darned fragile. Thankfully the gas valve died today and that made it a MUCH safer boiler.

Unknown

Ok

It might be a few minutes later. You start before I do....

I'll call you as soon as I get in.

Noel

Unknown

Look at pages 40 & 41

The boiler with the glass pipes made it all work for me, too.

Thank you, Dan. That day was the epiphany for me, too!

I took pictures for you. Here is the boiler, the glass plate in the front, the header that has to be big enough to carry all of the steam that feeds the mains with room for a BUNCH of water underneath it, and the equalizer that is NEVER big enough to get all of the water back into the boiler as fast as possible. This is the key to understanding water level problems. If the water that flies up the risers can get back into the boiler, uninterrupted, as soon and hot as possible, and not into the system, the waterline won't drop out of sight. If the waterline drops, and the HOT water is screaming up the mains, the boiler is going to see some pretty cold return water pretty fast. Ouch.

Noel

Unknown

Water line

When the boiler is steaming, that water line DOES indicate how much water is in the boiler and piping, but it DOES NOT represent how that water looks or acts. While the boiler water WEIGHS the same amount, in total, it is full of bubbles and is way up in the risers. The glass, somehow, indicates that that water really is still present, but here is what it looks like.

A-mazing.

Noel

Unknown

Consequences

We hear about water hammer, if the piping is incorrect, or if the water is oily.

Here is what it looks like when the boiler hurls water down a dry main and slams it into the elbow at the end.

Less the main and elbow......

The boiler water had a little bit of oil added to it. This is the result.

Noel