Baffling question! Help, please!

greg556

Hi--

This isn't a problem to solve, it's just something that is baffling to me that I would like to understand. I have one-pipe counterflow steam in my house. Here is a picture of the near-boiler piping for the return. It's all normal and correct. There are two drains for sludge. One is connected to the bottom of the Hartford Loop, and the other closer to the boiler. When I open the valve closer to the boiler, it dumps water out directly from the boiler, and can of course empty the boiler in a couple minutes. That's fine. My question is about the other valve. The way I am looking at the Hartford loop, it looks to me like the entire pipe of the Hartford loop, the lowest copper section, should be filled with condensate at all times, from the return line to the loop which is just a little below the water line. When I open that valve, all that water should drain out, emptying the copper pipe. Instead, only a tiny trickle comes out, not more than an ounce or two, not nearly as much as should come out to empty the whole Hartford loop.

So, there is something I am not understanding. How is that copper pipe not always filled with condensate?! Why doesn't it drain when I open that valve? Thank you!

Zman

Is it plugged with sediment?

JUGHNE

FIWM, I would take off the last 90, the nipple might be easier.
Then open the ball valve and stick a long enough rod into reach the 90 before the valve. It may be plugged there.

Jamie Hall

Are there any other pipes connected to that U shape copper assembly feeding the Hartford Loop? Granted, it shouldn't be just a trickle -- but the only water that will come out of that drain, once the water is below the Hartford Loop, will be what is in that U bend.

greg556

It can't be blocked, at least, that's extremely unlikely. The whole installation is only a year old, and this behavior isn't new--it has never been more than a trickle from that valve since it was first installed.

pedmec

It might be in a vacuum. Try draining with the relief valve open.

ethicalpaul

> It can't be blocked, at least, that's extremely unlikely.

If a pipe that is directly connected to a few gallons of water doesn't drain, I would say that it's in fact extremely likely that it's blocked. I mean, there's no such thing as magic.

greg556

Yes! That is what I think it is, some kind of vacuum lock. This is the exact idea I just had.

(To ethicalpaul, Yes, obviously it's blocked--the question is with what--sludge (almost impossible) or maybe air. I can "block" soda in a wide-open straw by holding my thumb over the top. I think some kind of vapor lock feels more likely to me, but I can't actually picture where/how it's happening. But I am going to see if I can make the pipes fill up. That's a good idea.

Here, here is a manufacturer's picture of the piping. The piping on my boiler is exactly the same except for one thing--the two drains on my boiler go *down* from the T rather than straight out as in this picture. Could that be a problem?

JUGHNE

Try the lift of the relief valve first.

If you want you could put a hose adaptor on the last 90, then using double female hose connections....like a long washer hose.....maybe from the bottom of your water heater; give it a shot of house pressure that might loosen junk.

The first 90 looks to be a street 90 type screwed into a reducing bushing.
That reduction might give you a collection point for junk.
That pipe is the lowest point in the return and will accumulate any return piping junk.

ethicalpaul

> (To ethicalpaul, Yes, obviously it's blocked--the question is with what--sludge (almost impossible) or maybe air. I can "block" soda in a wide-open straw by holding my thumb over the top

it does work with a straw, but try it with a two liter bottle, which has an opening even smaller than your pipe there. But regardless, good luck in your search!

EdTheHeaterMan

If it is a vacuum, then opening a vent or loosening a union or removing a plug in the vacuum section would release the vacuum.
if it is a vacuum, then by opening the pipe where the vacuum is located, the water will flow out.

Not sure where the vacuum is being created, but it is possible. To make sure the wet return can be flushed out, you can install a full port ball valve 28" above the water line (or as high as you can) then install a boiler drain just below the ball valve. Then you can pressure flush the wet return when ever you do maintenance.

However, if the system is working, and all you want is to understand what is happening, then I would file this under: "If it ain't broke...don't fix it", and the understanding part under "It's Magic"

greg556

Thank you everyone, I will try "snaking" it up to the loop, but it really can't be blocked with sludge, because the very first time after the new boiler was installed (one year ago) it was already just a trickle. This is a design problem or something, it can't be sludge accumulation. As for "if it ain't broke, don't fix it"--my concern is exactly what someone else said--the return NEEDS to be cleared out, or it WILL get blocked. It worries me that nothing comes out when I open that valve.

EBEBRATT-Ed

@greg556

If it is not in a vacuum, then it is definitely blocked.

109A_5

Hello @greg556,

I would fill the boiler (Blue circle) so it is definitely above the Hartford loop pipe (Blue line) and while it is still filling open the Hartford loop drain valve (Red circle) and see what happens.

greg556

Yes, thank you that is exactly what I did. (The water is always above the Hartford loop level, normally.) I opened both valves to drain enough water that it was several inches below the top of the loop level. Then leaving the loop valve open, I added water until it was above the loop level. Nothing changed. So, maybe it is a block--the question then is, what is the block? Is it possible for the plumber to somehow block a pipe when he's installing it? Is it even possible for the entire drain to become blocked in TWO WEEKS? Back to my original question: what is going on/what happened? Why do we always talk about sludge accumulating over years, if it can become completely blocked two weeks after a new boiler is installed?

(Do you think it's possible the installer managed to block the entire pipe during installation? (Maybe he was overzealous with the pipe dope? Or somehow crimped something?) Or was it a giant pile of sludge waiting in the pipes that was somehow loosened by the new boiler and traveled all the way down several feet of almost horizontal piping in order to get stuck in the drain pipe? All these theories are highly implausible--does anyone have a PLAUSIBLE theory? Thank you!)

bburd

The boiler and nearby pipes may be new, but the rest of the system is old. Sludge and sediment accumulated in the older pipes over time will flow down into the newer return pipes in the normal course of operation.

EBEBRATT-Ed

@greg556

It's not worth discussing what happened. Either the valve is defective and not opening only a little or something is blocked. It's an easy fix. Drain it and unscrew the pipe and see.....either you or your plumber.

JUGHNE

As I stated previously, the fittings at the bottom of the Hartford Loop are condusive to creating a pinch point. IMO

As the steam traveled thru the old system pipes it will wash sludge back and that lower cleanout you have is just like a P trap under a sink. Junk will settle in it.

The back flush with house pressure would tell you quickly.
If the water flows then it would start to fill the boiler as you can view the sight glass.

Fred

I'm thinking it is a bad valve that isn't opening properly, when you turn the handle. It just leaks a dribble.

109A_5

Hello @greg556,
Since it is assembled like a dirt pocket with a horizontal drain I would think it plugged up, especially if the return system of the boiler seems to presently work OK (no excessively slow condensate return). For the cost of a Plumber versus a pipe wrench or two I would just get the needed tools and take it apart, no more guessing, and then you will know. Then keep it clear so you don't need a Plumber.

With back flushing that may tell you too but then you are pushing the muck (if any) into the boiler and the return pipe instead of getting it out of the system. Which is kind of the point of having the drains, to get the muck out.

JUGHNE

You could back flush on the slow drain and then open the other drain to drain away any sludge that traveled over the HL and down.

Then once those are cleared up you could drain the boiler, refill and be sure to fire up to steaming to boil off O2.

mattmia2

Sludge blocking the valve or the washer coming loose in the valve and blocking it are possibilities, if you unscrew the valve (either be ready to put it back quickly or drain the boiler below the hartford loop), see if water comes out freely then. When there is little water coming out, does it stop or will gallons come out at a very slow rate?

greg556

I am surprised someone said that it's not interesting why the drain is blocked. That is the entire reason I wrote--to me it's quite shocking that either (1) so much sludge accumulated in ONE WEEK to block the drain pipe--if that's possible, it kind of destroys the entire assumed maintenance plan of draining the sludge every week, or (2) the pipe fitter somehow managed to block up a new pipe upon installation. That that is even possible, it seems to me, would be a good piece of information for people to have going forward.

I have fixed the problem. It was blocked. I bought a small snake and pushed it up around the bend. It would not go toward the hartford loop. I pulled it back out a few times. Want to know what was on the wire, interesting or not? Plumber's tape and pipe dope. Apparently the installer was so sloppy in connecting these pipes that he managed to leave so much tape and dope inside the pipe that it made the hole small enough that almost nothing could come out from the very beginning (which then may have contributed to a faster than normal build-up of sludge). I was able to push through and now the drain drains quickly.

If that's not an interesting "war story" to you, I guess we have different definitions of interesting.

mattmia2

They may not have kept the tape away from the very end of the threads and stretched a membrane of tape over the end of the pipe.

ethicalpaul

I admit I got confused by your timeline. You at first didn't say how old it was, then you did say it was installed a year ago and also said that it has been that way from the very start (which I admit I missed), then you said TWO WEEKS then you said ONE WEEK

But I'm glad you found the problem! Fortune was on your side because that is the one part of all your piping that is easy to get to from outside.

Now we all have to wonder what else the installer left inside your other pipes

greg556

EthicalPaul--I know, I don't WANT to imagine what else the installer left in the pipes! It's crazy. And yes, two weeks or one week--the point is it NEVER worked; not once has a full swoosh of water come out of that pipe (until this morning). I think I still do need to take off the last bit of pipe where the valve is and reach up and really smooth out that T from the condensate return to the Hartford loop. Crazy.

To Mattmia2--I am imagining that must be what happened--he wrapped the threads so quickly, he actually stretched the tape across the opening. Ridiculous. That is some serious not giving a **** about the quality of your workmanship.

Thank you everybody! With this mystery solved, I finally have this new boiler purring like a kitten. (I had to skim it TEN TIMES last winter and this fall to get the water clear and the water level not bouncing and no more water hammer.) Given what I just discovered, can you imagine the grease and chemicals he left in the water?!