Mysteriously missing make-up water

Curious_J

Since my new wife and I bought our first house about six months ago, I have spent many hours reading Dan's books as well as posts on this forum (interrupted by frequent trips to the basement to trace a pipe or apply a newly-learned concept) trying to understand the steam system we have in our basement. This post was originally intended to ask your help in understanding some things that would help me with a repair/maintenance/optimization strategy. However, I set the post aside for a couple days and in that time a much more urgent problem has arisen. Before I start with that, I will give you an overview of my system.

The System

• Two-pipe system that I believe is a Trane vapor system
  
• New Yorker CGS-A Series boiler circa 1998 rated at 245k input BTUs
  
• Honewell PA404 additive Pressuretrol (set at near .5 cut-in with an additive 1psi cut-out)
  
• McDonnell probe-type LWCO
  
• McDonnell electric solenoid water feeder
  
• American Radiator Co. tubular radiators with Trane valves and Trane B1 traps
  
• Main vents and return vent I believe to be Trane float vents (confirmation appreciated)
  
• The system heats a 2,900 SF house in southeast Michigan built in 1884
  

The Problem

I have had three boiler mechanics look the system over and, aside from a lack of documented maintenance, they all have generally had the attitude of "if it works, don't touch it". While, I do not feel the need to spend unnecessary money or time "touching" something for which there is no benefit, I am convinced I have some things that are not quite right that need to be addressed. The first among those was the not infrequent addition of make-up water. I work at home and would hear the solenoid on the water feeder "clunk" several times a week. I scoured everywhere that isn't between plaster and lath and have not been able to find any evidence of any leaks excepting a very small leak around the stem of a radiator valve. And, despite all of this make-up water being added, I have never seen the sight glass more than about two-thirds full.

Reading scores of posts that warned about the dangers of make-up water got me good an paranoid and prompted me to call in the mechanics. To make a long story shorter, I was told to have a blow down performed and that the addition of make-up water was normal. I clarified that the make-up water was being added nearly every day, if not every day, but again was assured it was normal.

It is now about a week after the blow down was done and the boiler now calls for make-up water multiple times during a single firing cycle. Worse yet, it calls for make-up water when the boiler is NOT firing about every 5 minutes - this is not an exaggeration. I figured that the boiler had to be losing water independent of its operation, so I turned it off at the switch (which cut power to the feeder) and waited. Sure enough, I came back in an hour and the sight glass was empty.

The Theory

After some head scratching, the process of elimination has guided me to a theory - please forgive me if I get terminology wrong or mix things up. The steam mains combine into one pipe and then go through a concrete floor and under a brick chimney (to complicate things) before it surfaces and ties into the wet return. There is no Hartford loop or anything to prevent water from draining out of the boiler (that I'm aware of) through the wet return piping. My theory is that the section of main/wet return that runs through the concrete floor has some serious corrosion that was potentially knocked loose/dissolved/dislodged by the boil down to make existing holes worse. This would allow water to be lost both during operation and simply through gravity when it is not in operation. Crazy? Is there any way to verify what the problem is?

I have attached some pictures.

Any thoughts, ideas, concerns, etc. are greatly appreciated!

BobC

Pipes that go under the cellar floor are suspect because you can't see whats going on and the harsh environment makes the subject to more corrosion.

While that boiler is actively making steam, step outside and see if you have steam billowing out of the chimney that means you may have a hole above the waterline in the boiler. If you don't have billowing clouds of steam the returns under the concrete floor are very suspect.

Bob

nicholas bonham-carter

Most likely the underground returns are leaking, but just to make sure, why not do the overfill test to verify whether or not the boiler itself is leaking.
Let the boiler cool a bit, and then fill it until the header is cold with fresh water, and let stand for a few hours. Look for water around and under the boiler.
If the boiler needs replacement, then make sure it is finally piped with a proper horizontal header and Hartford loop.
I can’t understand why these boiler mechanics thought it was normal to be adding water so frequently. Probably they are only used to process steam boilers, (in a bakery, or brewery), where the steam is lost, and as a result, the water must be replaced.
If the returns are suspect, then they can be replaced above the floor.—NBC

EBEBRATT-Ed

Probably a 90% chance that your problem is the under floor returns are leaking and that the boiler is ok.

But you need this fixed because raw MU water is no good,

Congratulations for learning your system and for being observant.....steam is a "hands on" system.

You can run the return on top of the floor to save installation cost if it's not in the way. Try finding a contractor who knows steam. You can use copper tubing for the wet returns.....and only for the wet returns nothing else.

There could be a complication however the piping may be covered with asbestos

Curious_J

Thank you for your quick and helpful replies. As a bit of an aside, I am excited about engaging more with this community. I have been scouring the forum for several months now and I have been incredibly impressed at how knowledgeable people are and how willing they are to share and teach what they know. I'm also impressed at the 'academic-type' culture that invites theories and allows it to be okay to not be correct.

As far as my current problem goes, I did what Bob and Nicholas suggested... there was no billowing steam from the flue and there was no apparent leaks when I filled the boiler up into the headers - the water disappeared, but there was no evidence of it on the floor or anywhere else. Thus, I am guessing - a little more confidently now - that the leak is in the buried pipe.

I had wondered if the replacement pipe could be run on top of the floor as Ed had mentioned. My contractor was on-board with the idea. However, he consulted with another knowledgeable boiler mechanic (who happened to be his competitor) and was told that the pipe could not be run on top of the floor because the underground section of pipe served as a hartford loop. So, as I understand it, taking up the concrete floor is my only viable option unless I want to put in a condensate pump (which would be much more expensive). My contractor suggests coating the replacement pipe in tar to prevent corrosion; sound like the best option?

Now that I'm doing this work, I have some other questions:

• I believe the main vents and the return vent are original to the system; one of main vents clearly vents steam, the return vent is audible (which I think I read is not desirable), and the other main vent is on a short main and the connected radiators are slow to heat. Replace all of them? What do you recommend? If this is a Trane Vapor System (confirmation appreciated), do I need a specific type of vent (containing a vacuum check valve)?
  
• Given that the Direct Return Vent is connected only to the return line, would it serve any function? Is it needed if operating at a low pressure? Should it be tested and/or repaired?
  
• Is there any way to test the two check valves in the return line (on either side of the riser with the direct return trap)? Are those still needed if operating at a low pressure?
  
• I just got done reading Dan saying that vents should not be at the elbows of mains or returns. Mine are. Yet a diagram of my system (or something very similar to it) shows the vents at the elbows (see embedded diagram). Should these be changed?
  
  
• Is there anything else that I should have tested, repaired, altered, etc. while this work is being done?
  
• Moving upstairs... my radiator traps are Trane B-1s, I believe.
  I have taken a few of them apart and they appear to have the original innards. Given that the assumed age of this system is 100 years +/- should these be replaced? I've heard that they have a very long life.
  
  

Any additional thoughts?

KC_Jones

I think you need to find someone more knowledgeable to consult. That is not functioning as a Hartford loop, in fact near as I can tell you don’t have one and an underground return, to an extent is quite the opposite of what a Hartford loop is trying to do.

As long as the pipe is below the boiler water line it absolutely without question can be run above the floor. The only restriction would be if there are doors or some kind of obstruction like that to prevent it being above the floor. Even with that there are ways to run it above the floor. No way would I personally bury a pipe in the concrete again.

Gilmorrie

Your system is maybe hot-water, not steam? I notice, from your pix, a circulating pump and an expansion tank.

gfrbrookline

Where are you located?

Have you tried the find a contractor on this page to see if there is anyone in your area?

Since your boiler is not sitting in a hole you should be able to reconfigure the return since it will be below the waterline.

JUGHNE

I see the exp tank....probably on the DHW tank.
Don't see a cir pump....older auto feed sort of looks like one though.

But do see sight glass, P-troll, pigtail....don't see a temp control on boiler. The real give away is the sight glass losing water. IMO

nicholas bonham-carter

Maybe we should all be wearing our academic robes while online!
I wholeheartedly agree with KC. The new return could be done in copper, maybe on thin tiles running across the floor. Leave a ball valve on a tee at each end so that the pipe can be flushed out later. If there is a doorway in the way, then it could briefly submerge under the floor. it will not need to slope, as it is below the boiler waterline.
Sailah is the resident trap replacement expert, although he has left Barnes and Jones to form his own company, he has a wealth of knowledge, and experience. He is away now for a few days, but will be back online soon. if you do a search for Trane system, you may find he has answered that question for someone else about the modern replacement. Do you know that they are not working?
Maybe Steamhead can answer the other check valve, and steam line to Direct Return Vent question.
Offsets could protect the main vents on top of the risers.--NBC

KC_Jones

Actually thinking further, the reason you can empty the boiler with an underground leak is entirely due to the lack of a Hartford loop. It’s specific purpose is to prevent a low or underground return from draining the boiler to an unsafe level, quickly.

Fred

It has to be a leak in the buried wet return, otherwise the boiler would not empty while it was not running. If it did, you'd see water somewhere on the floor. As has been said, anyone who tells you the buried wet return is acting like a Hartford loop may be smoking something AND I want some of it! Replace it and put it above the floor, if you can route it so that it doesn't obstruct anything that poses a problem for you. Just make sure it stays below the normal boiler water line. I don't see an equalizer on that boiler either (unless I just can't see it from your pictures). It isn't piped correctly so you may want a REAL steam Pro to evaluate the near boiler piping and add an equalizer and a Hartford or Gifford loop.

EBEBRATT-Ed

You need someone that knows steam. The under floor pipe does not serve as a Hartford loop and has nothing to do with a Hartford loop. They don't know what they are talking about

Ying

My returns are all above ground right on top of the basement floor. Dont see any reason why yours can't be. Don't think the pipe under the floor has anything to do with being the harford loop. Just make sure the return is below your boilers safe operating watet level and finish the loop next to the boiler.

Curious_J

KC_Jones said:

That is not functioning as a Hartford loop, in fact near as I can tell you don’t have one and an underground return, to an extent is quite the opposite of what a Hartford loop is trying to do.

KC, that is my understanding of the purpose of the Hartford loop: to prevent an excess of water from draining from the boiler should something go wrong with the return lines. If this below-ground pipe was intended to do that (and I cannot understand how it would), it failed miserably and actually facilitated the drainage.

Gilmorrie said:

Your system is maybe hot-water, not steam? I notice, from your pix, a circulating pump and an expansion tank.

Gilmorie, it is definitely steam. Jughne is correct, the expansion tank you see is for potable hot water. There is no water pump of any kind.

Fred said:

Just make sure it stays below the normal boiler water line. I don't see an equalizer on that boiler either (unless I just can't see it from your pictures). It isn't piped correctly so you may want a REAL steam Pro to evaluate the near boiler piping and add an equalizer and a Hartford or Gifford loop.

Fred, I assumed that the vertical pipe circled in red in the embedded photo below was an equalizer; is it not? Is there a reason that the diagram I posted in my previous post (which is substantially similar to my system) does not have a Hartford loop? Does the Trane Vapor System predate the Hartford loop?



I am in SE Michigan and I spent months trying to find a good steam heat person who was familiar with these old systems. The outfit I am working with came highly recommended by a reputable contractor colleague. I gather there are not many around this area that truly know the old systems.

In regards to going underground vs above-ground: I do have to go under a doorway and a chimney that is solid and nearly 3'-6" wide. Ultimately, it looks like it may be cheaper for me to go under rather than do the boring and other things to keep it above ground. Given that it is ultimately cheaper, is it a major mistake to go below ground? Is there a "best practice" for doing this?

Thank you all for your help and feedback!

KC_Jones

Curious_J said:

KC_Jones said:

That is not functioning as a Hartford loop, in fact near as I can tell you don’t have one and an underground return, to an extent is quite the opposite of what a Hartford loop is trying to do.

KC, that is my understanding of the purpose of the Hartford loop: to prevent an excess of water from draining from the boiler should something go wrong with the return lines. If this below-ground pipe was intended to do that (and I cannot understand how it would), it failed miserably and actually facilitated the drainage.

That's my point, when the Harford loop was developed it was so that if you had a leak in the wet return it wouldn't drain the boiler. You do not have a Hartford loop on your system and the assessment by your professional is dead wrong, further keeping them underground has zero to do with a Harford loop. The only thing that matters is keeping the return piping below the boilers water line.

Your boiler isn't piped correctly. I am not 100% sure what that large vertical portion is connected to the risers, but I seem to recall companies making some kind of steam drum separator.

The pipe you circled in red might sort of act like an equalizer, but it's not right as near as I can tell. Remember the equalizer not only equalizes pressure, it gets the water from the header back into the bottom of the boiler. I don't see how that will work on yours. Actually I don't see any way for the water to get back other than the boiler risers, which is certainly costing performance.

As far as the return, keep in mind it doesn't have to run exactly where it is now. It needs to connect point A with point B and stay below the water line. I would still be inclined to try and keep it above ground so I can see what's going on with it and save the money on busting up all that concrete. If you are set on going underground I would definitely go with copper.

Jamie Hall

Southeast Michigan does seem to be a bit of a black hole for steam. However, steam is so easy to learn to do right that a really good plumber, not afraid to learn new things and not afraid to thread pipe, will do just fine.

And perhaps the very first step -- at least where I started anyway! -- is to figure out why certain things are the way they are, and how they are supposed to work. Then you can work variations on them, as needed for a particular system.

So, in that vein... Haftford loop. It's purpose is simple: to prevent water from leaving the boiler into a leaking wet return. To do that, it is tied into the boiler below the water line, turns and goes up to the design water line (Hartford) or above (Gifford), turns horizontal for a short distance -- shorter the better -- then turns and goes back down a picks up the wet returns. However, it also needs a vacuum break at the top, otherwise water cold siphon out. The system also needs to have pressure equalization between the steam lines and the wet returns, and a way for condensate in the header to get back to the boiler. Voila: the equalizer, which goes from the low end of the header to the top of the Hartford loop.

It isn't bullet proof: while it will protect against a major leak in the wet returns, it won't protect against a leak in the boiler, nor against slow steam loss or leaks in the system. Therefore, you also need at least one low water cutoff.

On underground wet returns. They are sometimes unavoidable, though not a really good idea. If you have to put one in somewhere, it should be heavy wall copper -- not DWV! -- and it wouldn't be a bad idea at all, if you are starting from scratch with one to put it in a larger sleeve, which could and probably should be ABS or PVC drain pipe. Bring it to the surface with fittings arranged in such a way that you can get at both ends of the underground section with plugged Ts, so that you can flush out the underground section when and if you need to. Enclosure in a sleeve -- same as you would for a buried oil line! -- will alert you to a leak if there ever were to be one, and make replacement easier, should you ever need to.

Grallert

I have a couple of pictures take of a buried return I replaced this past summer. We love pictures. But darn if I can't get them out of my phone onto this computer. It's pretty remarkable how much water can disappear into the ground.

Grallert

Grallert said:

I have a couple of pictures take of a buried return I replaced this past summer. We love pictures. But darn if I can't get them out of my phone onto this computer. It's pretty remarkable how much water can disappear into the ground.

looks lik
looks like I found them

Jamie Hall

That's ugly...

Curious_J

A picture is worth a thousand words and those say it all!

Now I'm worried about all of the dirt and sediment that has been picked up and deposited in the piping and, especially, in the boiler. Oye!

BTW, I'm looking for ways to keep my replacement above the floor.

Curious_J

I understand the basic premise of a Hartford Loop, but I am sure I will have some specific questions when I can get down to my basement and try to apply it to my scenario.

KC, you mentioned that the boiler piping - and I assume you are referring to near boiler piping - is not piped correctly. I have heard this from others and I also got a sense of that from reading Dan's books. My primary questions are one of pragmatics: a) how much benefit will I see from re-piping the near boiler piping and b) is there harm in leaving things as is? I want a proper installation; however, until my underground leak, the system was working quite well and I had no significant complaints. If the cost is $x,xxx and the benefit is a savings of $xx a year or is largely theoretical, I may well wait until I need to replace the boiler. (The asbestos removal may be the most costly part of the job as most outfits have a minimum full-day charge.)

JUGHNE

Is all of the radiation on the floor above the boiler?
It might be possible to turn your wet returns into dry returns.
Could be an issue with head clearance though, was most likely one of the reasons for burying them.
But new piping could be dry returns and then drop in the boiler room as wet returns and then into a new Hartford Loop.

How are the wet returns vented now, before dropping down to below the floor?

Fred

@Curious_J , That pipe you circled (in your last picture is not an equalizer. It looks more like a Drip, to me. This system looks like it is at least partially a Counter Flow System, meaning that some or all of the mains slope back to the boiler. Are any of the mains pitched back with the lowest point at the boiler. It may be that the main pitches back to the boiler and then, somewhere along the main, it starts to pitch the other direction, hence the buried wet returns. There are a lot of pipes there and it's difficult to put them all into perspective, from these pictures.

In any case, the biggest benefit in re-piping the near boiler (clearly replacing the leaking wet returns is a priority) but you need a proper Header and each main needs to tie into that header. That Header allows water droplets to fall out of the steam before it enters the Mains. The Header needs a slight pitch towards a proper equalizer at the very end of the header so that that water can run down it and back into the boiler. Dry Steam is essential to an efficient steam system. You need a Hartford Loop to ensure another leak, below the boiler water line does not fully drain the boiler. It the boiler fully drains, you could have a dry fire which can be catastrophic. Vapor systems are wonderful steam systems and must be run at typically less than 8 ounces of pressure. It needs to be piped correctly to take advantage of the potential it can offer. Having said that, all steam boilers need to be properly piped to provide the best comfort and reliability. Dry steam is essential to their performance. Can we say how much annual savings there might be with a properly piped system? Not likely.

As has been said, finding a good steam Pro in Michigan has been a challenge but, if you understand how it needs to be piped, find a plumber or heating Pro who is willing to work with you and learn, you can manage the installation as it progresses, with the help of the people on this site and you can get it done.

Grallert

Jamie Hall said:

That's ugly...

It was hard to tell where the cement and soil stopped and the pipe started. My rough guess from my water use so far this season is I'm saving about 5 or 10 gallons of water daily. This short length about five feet is the only buried return. The replacement is wrapped in protective PVC tape and insulated. I think this is my last truly ugly issue.

Curious_J

@JUGHNE Yes, the boiler and piping that you see in the pictures is all in the basement - all radiators are above this. They are vented with, what I believe are, Trane Quick Vents. You can see them in the first picture on the first post of this thread. If I implemented your idea of extending the returns over the doorway and then dropping them down, would they need to slope toward the boiler?


A couple basic general knowledge questions that have been puzzling me: What is the point of the steam main tying into the wet return on a two-pipe system? Does the cooler main and risers condense the steam and the connection to the wet return allows for its return to the boiler or does it have to do with pressure equalization or something else entirely? Also, can somebody help me to understand what is happening at the union of the wet and dry returns as shown in my sixth picture. I'm having trouble thinking like steam here. The condensate water starts to fill the vertical pipe of the dry return and the water is being pushed up through the floor (?) by the pressure of the steam in the main (am I right, so far)? Then, what is the interplay and and what forces lead them to the boiler (which is about 4' to the right in that picture)?

Jamie Hall

@Curious_J -- I think I have figured out which system is yours and which is Paul's here...

So let's get some basic terminology straight here, first, so we can agree on what we are saying. Note that my usage differs some from some other folks for one pipe systems, but not for two.

Steam main: this is a pipe which carries live steam at, or very close to, the pressure generated by the boiler. Runouts or risers to the inlets of radiators come off this line. A steam main may or may not be vented, depending on the system. See dry return.

Dry return: this is a pipe which carries air forced out of the radiators through the traps and condensate from the radiators. On some systems, it also carries air forced out of the steam mains through crossover traps. It must be vented to the atmosphere.

Wet return: this is a pipe located below the water line of the boiler which accepts condensate from the steam main(s) and dry return(s) and connects back to the boiler through the Hartford or Gifford loop.

Now. Steam mains produce condensate, and dry returns carry condensate from the radiators. Therefore, there are pipes called drips which carry that condensate from them to the wet return(s) so that it can get back to the boiler. Water will stand in the drips at an elevation controlled by the water line in the boiler and the pressure in dry return or the steam main. The pressure in the dry return is, or should be, atmospheric -- 0 gauge -- so the water in a drip between a dry return and a wet return will have to be higher than the water line; 28 inches for every pound pressure in the boiler. The pressure in the steam main, however, is the same or very nearly so as the pressure in the boiler, so the water in a drip between a steam main and a wet return will stand at about the same level as the water in the boiler.

Curious_J

@Jamie Hall - Thank you; that was very helpful! I've spent hours staring at that section of piping, scratching my head, and trying to visualize the steam flowing through the pipes. So, at normal boiler pressure of less than a psi, the check valves are unneeded - the height of water in the drip in the dry return will not get higher than 28 inches per psi and the water coming in from the dry return will add to the head of water and push it down into the boiler until it reaches that 28 inches per psi height again?

Jamie Hall

Got it. In fact, the check valves rather get in the way. If you can keep the pressures under control, gravity does all the work for you -- and needs no maintenance!