one pipe condensate around a door

Dave Gray

I added a doorway in my basement and had to relocate a condensate line that was 20" above the floor. I made a u loop in the floor. My water line is at 25" above the floor. I remember, but can't find , a picture of a pipe going around a door that both went above and below. Is that only for steam and I'm OK with what I did on condensate? I have the Lost Art of Steam Heating, but can't find any reference in it. Did I miss the page?

Brad White_15

One detail I use

(Not sure it is in THE BOOK but it may be) is that the return pipe approaches the door horizontally into a tee branch connection and then drops below the door. (Trench or sill concealment with plug tees for cleanout if you like.)
When the horizontal continues on the other side of the door it resumes with a tee at least one inch lower than the upstream side of the door.

(At the drop/rise on each side of the door you will note that there is a tee. The branches of the tees face away from each other across the door. The mains of the tees are in the vertical.)

There is an air loop which extents over the door and connects the tops of the tees. (Easier to sketch than describe apparently!) The configuration is a big "O" around the door; condensate below, air over the top.

But you can see the goal is to promote flow by a difference in height across the door and the air loop over the door acts as a vacuum breaker to keep any suction created from holding back the flow.

Brad White_9

Detail

Let's see if this detail "sticks":

Long Beach Ed

If it is a wet return, which is what you describe, what you did is correct. You would only need to loop above the door if the pipe was carrying steam.

Long Beach Ed

Brad White_9

My mentor

Ray Stevens (one never questioned Ray, rest his soul) insisted on the air loop due to its anti-siphon effect. His concern was that a large slug of condensate would hold back flow downstream. The air loop relieved this so the incoming line never filled above the first tee.

Probably no harm leaving it in but I do see the value if it also carried steam. If it were steam-bearing, I would size the "air" loop larger for the steam load and condensate the same or smaller, sort of inverting the detail.

Thanks for the thought though, Ed, something to chew on..

Dale

page 95

In lost art pg 95 Dan shows a steel beam offset, steam being a gas the detail should work just as well for a door.

soot_seeker_2

Thanks, Brad but...

Thanks, Brad, let me see this...

Ray felt that slug of water filling the pipe laying low, say under a door would hold back the downstream water. Wouldn't the weight of the upstream water push the water through this "invert"? Certainly this invert would never drain, but water spilling into it would displace water pushed out of it.

Tell me what you think. If you're sure that this is the application he ment, I'll look further into it. We'll even build one if we have to and give it a try.

Ed

Brad White_9

I had trouble grasping

that at the time (and learned never to argue with Ray too much) but he did teach me to think... This was all explained to me in the late 1970's when I was just starting out, so the rationale is worth re-visiting.

I always saw this the way you did. "In-ee equals out-ee" and that weight/mass rules when gravity is imposed. Most of the time.

But Ray insisted on the "soda straw" theory and wanted to allow the breaking of vacuums especially in gravity flow situatations with low differentials in height. Nature abhors a vacuum, and so, apparently, did Ray.

He was aware of vapor-lock, flashing and giving non-condensibles a path, a place to go. He could visualize a system in an instant and could walk up to a problem, so this is one thing I took on faith. But the detail has been published elsewhere (for condensate, never saw it for steam except around a beam in the Carrier manuals of yore), so perhaps it is an article of faith from a Dead Man.

soot_seeker_2

Brad...

...after this economy goes total bust and everyone is finished spending their refinancing money and I am laying around with nothing to do and have split open every ancient sealed steam vent in the shop to see what's inside, we'll conduct experiments and let you know the outcome on this one...

Ed

Brad White_9

Ed-

You are the MAN! Cannot wait to see the results....

Still, I used the detail for years without incident. Of course, Ray, the man who gave it to me, is dead... lotta good it did him....

Unknown

Here's some pictures...

There are more than one because I wasn't actually taking pictures of the return going under and over the door. This was a 2 piper vapor system, but the theme is the same...

(excuse the clarity, the building was on fire)

Noel

soot_seeker_2

\"Returns Containing Air\"

Yes, I've seen the detail used many times in the old books. Never as pretty as in your pictures, but never in a burning building either.

The 1936 ASHVE Guide shows the detail with the note: "Sutable for any dry return line and any return line carrying air".

I suppose this would include a gravity wet return. Without the air pipe around the door, air would avoid dropping down below the opening and accummulate at the elbow.

By 1939, the Guide showed the same detail but only noted "for dry returns". Maybe something happened to the way air behaved sometime between '36 and '39.

Ed

Unknown

actually...

This was originally piped (I believe) as a dry return, with the boiler originally lower, in a pit that has been filled in. Steamhead and I found another building like this, and one that the boiler was STILL in a pit. In this building, that return IS dry, and there is a boiler feed pump in a pit in the right foreground of this picture. The 1" iron pipe across the floor is the pump line to the back of the boiler.

The supply side consisted of a (dripped) express riser that went straight to the attic, and there were perimeter mains around the attic that fed down through the building. The building, and the basement, had convectors in it that used this return all of the way around the building.

Noel