Puzzling over pitch

Ed_10

I have single-pipe steam in my house. Assuming it is the original, the piping was done 101 years ago. I recently had the asbestos insulation removed from the pipes, which made some sagging clearer. I want to correct that before reinsulating. Here's the question:

The system has the boiler in the middle of the house. It feeds two loops via a T above the boiler, one totalling 50 feet oriented site-east, and the other totalling 50 feet site-west. On the site-east loop, the main runs 20 feet horizontally, i.e., dead level, from the T over the boiler (checked with string and spirit level), turns, goes a yard, then drops via a couple elbows and returns to the boiler at a pitch of a half inch per 20 feet.

The other loop is similar, except there rather than being horizontal, the main *rises* at about inch per 10 feet before looping around and pitching back to the boiler.

So, this system will return some condensate to the *steam
header* rather than to the return because of the slopes on the first runs of the mains.

Is that OK?

The system doesn't hammer (even uninsulated), heats well. There's some gurgle in two spots...so maybe its on the edge. I need to decide if this has to be corrected before I reinsulate.

Thanks. Oh, all the returns are dry returns. And, I've seen a diagram of a counterflow system. I don't think that's what this is because those mains sloping back to the boiler slope to the header, not to a return and because they eventualy turn and pitch back to a return.

Steamhead

Both mains

should pitch down from the boiler. The house may have settled, altering the pitch. If you slightly lengthen the pipe hangers at the ends, you should be able to re-establish the proper pitch.

This would also be a good time to add main vents to your system. If the steam-carrying portion of each main is 20 feet of 2-inch pipe, a single Gorton #1 or Hoffman #75 vent should be installed at the end of each main before it drops into the dry return.

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Ed_10

Steamhead: Thanks for the reply. On one loop, I think I can reslope. On the other loop, because of runs to radiators, I don't see how. In other words, I already experimented and determined that if I go so far as to let the mains hang from the first floor radiators (!!), I'd not get the pitch to go down from the boiler. And, unless the house settled UP, I'm not sure how to blame settlying. That's why I was wondering if the guy who built this did something clever.

Oh the other problem on that loop: If I drop the end of that loop so that the main pitches down away from the boiler on the outbound leg, I'm going to loose the 1/2" per 10 feet on the pitch back to the boiler for the return.

Venting mains: there's one installed at the end of each main, about a foot back from the last elbow that drops down to the boiler for the return. On the tune-up list is to replace those with new or have the Boiler Man convince me those are good or can be cleaned.

Steamhead

In that case

you might have to do a little pipe work to get the right pitches. But the results would be worth it. This may be more than you want to handle- try the Find a Contractor page of this site to locate someone near you.

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Ed_10

Steamhead: thanks again.
I'll see what the boiler guy says when he comes. And, I
do see how to blame settling, without needing the house to settle up :-). The basement floor is junk. I could easily see the floor under the boiler settling the half-inch, although the boiler is level now. It's up on some crumby cement blocks...maybe a hint that someone leveled it but also inadvertently dropped it down.

Out of curiousity: I noticed there's an equalizer between the steam header and the return on one of the loops, but not on the other. (The two loops return to opposite sides of the boiler and share nothing in common except that T where they originate over the boiler.) Why doesn't water push out of the boiler into the loop without an equalizer?