Finding a leak in underground return line

shelley77

I must have a hidden leak in my underground return line - I was losing 500 gallons a day the last week of April 2017 until the weather got warm and I was able to shut the boiler off. I have a 21 unit multifamily and it's a single-pipe steam system. After I shut the boiler off, it took about 2 hours and the boiler was emptied of water completely. The boiler room is as dry as a bone, as are the areas around the visible return lines. Any suggestions on how I find the leak?

ScottSecor

Is the smoke pipe/breaching rusty? Is the boiler cabinet rusty or is the paint chipping off? Does your boiler have an atmospheric burner or does the boiler have a power burner? I would not rule out the boiler just yet.

Harvey Ramer

I would try a THERMAL imaging camera.

EBEBRATT-Ed

If the boiler was still running you could walk around on the floor in your bare feet and find the warm spot.

Or better yet get a cat. It will find the warm spot to lay down on.

Where the leak is isn't the problem, how to fix it is. You need a steam guy who is creative. all the pipe under the floor is probably shot. You may be able to run the pipe above the floor to avoid breaking up all or part of the floor. A condensate pump may be part of the fix, like I said you need someone who is creative

gerry gill

I agree with Ed- the whole underground is likely deteriorated to the point you wont be able to just fix one spot. Or if you do, you will be back at it again in short order.

MilanD

Hartford loop should not allow boiler to drain out completely and through the wet returns. That is, if there is Hartford loop, but one should be there. What boiler is this and how big? What's below it? Is there a condensate return tank?

shelley77

It's an HB Smith 28A-S-6 using #2 oil. It was installed 15 years ago, there is concrete below it, which was installed at the same time. There is no visible rust on the boiler. There is a Hartford Loop. I don't know what a condensate return tank is, but I don't think there is one - some of the return lines are buried.

ratio

The condensate tank is where the buried lines drain to, then it is pumped into the boiler—unless the boiler is lower than the buried lines. I solved a similar problem with the help of a Fluke VT-04. Led me right to the leak, then I paid lots of $$$ to have it dug up & repaired, but no more leaks.

shelley77

The boiler is definitely NOT lower than the return lines - does that mean there must be a condensate tank?

ratio

As long as gravity works the same there as here, water won't drain uphill. I totally dropped the ball here, pay no attention. But the next part still holds:

Maybe post a few pics of the boiler so we can see what it looks like?

nicholas bonham-carter

The Hartford loop would prevent the boiler from becoming completely dry, from a leaking return, unless you mean there is no water in the glass.--NBC

Jamie Hall

Oops... the boiler can be higher than the wet returns. What happens is the that water stands at the far end of the wet returns at the same level as the water in the boiler when the whole thing is off. Which means, among other things, that the wet returns are... wet... All the time. There is no need for a condensate tank with wet returns below the boiler. There is no need for a condensate pump, either. Gravity does the job.

Wet returns can and do develop leaks, though, and as has been said if you have one you are likely to have a whole lot more following right along after.

ratio

Oops indeed, I hadn't thought of that. I'll edit my response above.

MilanD

How can the boiler drain dry if there is a Hartford loop and, apparently, boiler it self is not leaking? From a leaking wet return, water in the boiler would drop 2 inches and stop there. No?

Fred

MilanD said:

How can the boiler drain dry if there is a Hartford loop and, apparently, boiler it self is not leaking? From a leaking wet return, water in the boiler would drop 2 inches and stop there. No?

A Hartford loop will buy you a little extra time but the boiler will continue to boil and make steam up until the time the LWCO kicks in and that's well below the Hartford loop

MilanD

> @Fred said:
> How can the boiler drain dry if there is a Hartford loop and, apparently, boiler it self is not leaking? From a leaking wet return, water in the boiler would drop 2 inches and stop there. No?
>
> A Hartford loop will buy you a little extra time but the boiler will continue to boil and make steam up until the time the LWCO kicks in and that's well below the Hartford loop

Op said: turned boiler off and after 2 hours it was dry.

KC_Jones

The OP stated it went dry when shut down. Steaming isn't a factor then.

Fred

KC_Jones said:

The OP stated it went dry when shut down. Steaming isn't a factor then.

True, In that case I would have to suggest what the OP is calling a Hartford Loop is probably the pipe coming up, out of the concrete floor and tying into the Equalizer off of a Tee right at the bottom of the boiler.
A Picture would certainly help!

shelley77

I'll post some pictures tomorrow - thanks for all the help!

shelley77

And I did mean there was no water in the glass, not that the boiler was completely empty.

MilanD

> @shelley77 said:
> And I did mean there was no water in the glass, not that the boiler was completely empty.

Yep. Wet return will need to be rerun. Pics will help on deciding how best to do it. There is a post here from earlier of a gentleman that rerun them in 1" copper and ran them inside/on side of the basement wall.

EBEBRATT-Ed

Smith 28-6 is probably around 1 million input, that's a guess I didn't look it up. This is not a house boiler.

there may or may not be several ways to fix this correctly, maybe the old returns need to be dug up maybe not.

It's going to take a lot more than 1" copper to fix this one

Depends on the type of system. Your best bet may be a condensate pump. No one can give you the correct fix without seeing the job

MilanD

EBEBRATT-Ed said:

... It's going to take a lot more than 1" copper to fix this one

Depends on the type of system. Your best bet may be a condensate pump. No one can give you the correct fix without seeing the job

Agreed. Steam man/woman will have to see it to evaluate.

My point with redoing return is that the wet return may be ran on surface or at the wall below water line and not buried as long as it's feasible. I'd stay away from return tank, having one and not liking all the blowdowns and an extra float, motor, tank, etc...

There are wider copper tubes too and may be ok to use it in a wet return application, matching tubing size to black iron that rotted away. My point here was that someone posted his redo of leaking buried wet return that was done in copper, and done quite skillfully, which happened to be 1".

Sorry for the confusion.

shelley77

here's some photos:

shelley77

more

shelley77

shelley77

Pictures in order:
#1 front of boiler
#2 rear of boiler
#3 burner
#4 feeder
#5 Hartford loop
#6 rear view - return line on left floor
#7 another return line
#8 same return line as #6 from the front
#9 side view of boiler

Fred

I'm trying to put the height of that Hartford loop into perspective with the sight glass on the front of the boiler and it looks to me like the Hartford loop is still below the bottom of the sight glass. Is that the case?

clammy

If you are sure it s in your buried return you should get isolation valves installed at the ends of the mains and drips and do a pressure test to confirm thats where your leaks are and if so i would look into running them new and exposed returns as long as there well below your noilers water level .Its alot of work and possible difficult but in the long run much cheaper then the condensate pump ,reciever and feed tank and bs and much less maintance in the long run gravity retruns no moving parts beats pums everytime peace and good luck clammy

Charlie from wmass

after reading this thread there is only one thing that you need to do and that is replace your wet returns. There is no more testing there is no more magic that can be done.

jimmac

Shelly ,your boiler looks to be a Weil McLain 88 series not a Smith, but ask Entec what your flue sensor is reading as well. Your smoke pipe show's the first signs of a bad/cracked section.