pressure testing an old system

SteamedInDC

We have a 14 unit building with 50 radiators, a two pipe system and a Weil-McLain 780 boiler and have had a water loss problem that no one has been able to identify with any certainty. On a bad day we may see 60 - 80 gallons of water fed into the boiler through our VXT Feeder. The building is almost 100 years old and has not been well maintained. One hypothesis is that it could be all of the valves and traps could be leaking since they have been poorly maintained. Could a building with this much age and that has been poorly maintained withstand pressure testing the pipes. I've read another thread by Long Beach Ed talk about this technique to find leaks.

There are no buried pipes, we've crawled around in the crawl space, we've look in the boiler room, looked in the flue, looked at what's coming out of the flue and we haven't had any luck.

We'd like to consider doing a pressure test, but don't know if its the right option for the state of the pipes.

Any thoughts on doing this test to buildings this old?

Thanks,

Jamie Hall

Ah... well... I wouldn't. Not so much that the pipes couldn't take it -- they probably could -- but if you used water the radiators and traps might well not, particularly on lower floors, and the vents certainly wouldn't. And you can't use air, as the vents won't close on air.

That said, that much water use indicates a really huge amount of leakage somewhere. Much more than I would expect from leaking vents or valves.

JUGHNE

Just more crazy ideas.....I recall reading in one of Dan's books about a building that had a terrible aroma whenever the steam come up. Well that case was a 1 pipe system with a disgruntled employee/supt. He would collect his urine every day and add it to the boiler during down time at night. This didn't bother him as he was in the basement with no rads. Everyone else had a 1 pipe air vent on the rad in their apt.
This is a 2 pipe system so there should be no venting anywhere in the building living quarters? So could some civil/sanitary odorant be added to the boiler water. Say something mildly offensive as vinegar? Or if you never told anyone you could try the Supt. special liquid (just kidding).
Some where the odor would show up and at least give one a general area of leakage.
Or even better might be a trace liquid dye that would boil to a vapor and then condense back to a colored liquid when exposed to air. We use that in refrigeration with the UV lights for leak detection (Spectronics Corp).
Whatever the mystery additive is it would have to not affect the boiler, or water and be easily flushed out of the system.
Actually the refrigerant dye stays in the system and would expose any new leaks with the use of the UV light. Think about how complex the refrigeration cycle is involving oils, liquid and vapors and any state in-between those phases; plus the extreme temp changes involved are more drastic than steam.
So just another crazy idea waiting to be developed and invented. (Just remember if this comes to pass that my name is attached) Also don't try this at home.

nicholas bonham-carter

Start by overfilling the system-with water, let it sit for an hour or two, and then examine the boiler, and the returns for leaks. If it is not coming from the return piping, then it could be the boiler itself.
If the boiler is the culprit, then resize all the radiators to properly size the replacement, and do not simply go by the rating of the old boiler, which may be wrong.--NBC

vaporvac

Re @JUGHNE‌ , I have read here of using peppermint essence.

nicholas bonham-carter

Better than urine!--NBC

JUGHNE

Some tenants are reluctant to call landlord in, for a variety of reasons. Something pleasant like peppermint may not instigate such a call. However vinegar (or worse) smell and your phone would ring.
But 60 gallons a day very well could be going up the chimney. I assumed they would already have done the boiler flooding test.
Back to the disgruntled Supt. could someone be "borrowing" water from the boiler? (nasty water though).

SteamedInDC

what about putting peppermint essence in the boiler water and letting the system run? assuming that there are no vents on the radiators, if a unit smells of peppermint, then there must be a leak or more. The one example I heard about with peppermint essence was associated with a pressure test. Is there any concern about damaging the boiler with peppermint essence?

RobG

I would suggest calling Dan Foley the principle of "Foley Mechanical". He is the premier steam expert in the DC area and I'm sure he can find and fix your problem. If Dan is to busy you can try Frank Wilsey of "All Steamed Up" out of Baltimore. He might be willing to make the trip. Either way, you need a pro to save your system. Both of these people can be found in the "find a contractor" section of this site.

SteamedInDC

Thanks RobG, Frank is going to be down in March. Hopefully he'll be able to find the source(s) of our woes.

ChicagoCooperator

Have you (I assume you have, but I'll ask again) gone through and checked that all the valves are leak-free, etc? Also, is the read-out on the auto-fill accurate? That's a truly massive amount of water to be leaking out everyday! Unless you have one of those new roof mount vents or building side ice maker/sprinklers...

JUGHNE

I have seen one old system where one of the boiler mud leg drains was piped directly thru the concrete floor and into the sewer. They did not like water running on the floor to the floor drain when there was a drain down. Of course there was a globe valve on the pipe. This has since been corrected and we get the floor wet as needed.
However if you had a set up like this any valve with some years on it can fail and pass water without you ever seeing it happen.
This is a real long shot; but in a 100 year old bldg. there are probably dead pipes and surprises all over the boiler room.

No one has asked for pictures yet? Always good to see some.
When did the water usage start? Or did were you just made aware of it when the VXT feeder was installed.

Long shot #2: Original under floor wet returns were abandoned some years ago, replaced with new dry returns. Far ends of wet return pipe were capped. Then on maybe a boiler change out the boiler end of wet return was reconnected (along with newer dry returns) to the return system and is leaking water (back feeding)under the floor unnoticed until now.

SteamedInDC

JUGHNE - these are good questions, I'll answer what I can

I moved into the coop building about the same time as the new boiler was being installed. The boiler is 1 yr. old Weil-McLain 780 gas boiler. It was installed by a contractor that really botched the job. We had the have all of the near boiler piping redone, the header and equalizer were done 3 times. We think we have everything properly installed now but we fired that installer. Below are my observations:

From what I can tell there is no pipe from the mud leg to a drain.

We checked out water bill, it seems like this problem was also going on while we had our old boiler, we didn't have a water feeder with a read out, (or no one was paying attention) so we are assuming the water loss is in the system and not the boiler.

From what we can tell, supply and return system are hooked up properly. We have had one plumber say that perhaps the return system has been mistakenly connected to a plumbing waste return over the years. That would be a hard one to track down, but not out of the question in this building.

I'll post pictures later

JUGHNE

Are there any pipes coming out of the floor connected to the boiler or any of its piping anywhere in the system that you can see?
With the boiler running a good flow of steam & assuming you have cast iron drain pipes you could look for one that is consistently hotter than others using an infrared thermometer. And also a cold/cool condensate return line would be suspicious. Hopefully you have access to some of these. That IF thermometer works best on dark surfaces; not so good on copper or PVC.
Maybe part of your return got connected to the drain somewhere; if so it should be still accessible unless remodeling was done. Surely not done a 100 years ago? If so that would have be the death of several boilers.

SteamedInDC

No pipes coming out of the floor and connected to the boiler.
I'll start feeling the waste pipes to see if they're warm
One of the return lines starts out cooler than the two others. We've been able to trace that to a open concrete trench that goes under one of the tiers of apartments, but don't see anything yet.
At least that limits us to 4 units to investigate.
Lots of work has been done to units over the years, they had a dopped up plumber for years that did some really messed up work. Lots to attempt I untangle.

nicholas bonham-carter

If you have done the overfilling test by now, what did you see? If not, then why not?
If not then remember, that it only needs about a foot or two of water above the header to equal the same pressure as the steam.
Let us know what the results were.--NBC

icesailor

Look to the plumbers:

The use of Peppermint Oil to find waste or any leaks is a common use of the product. Pour some into the boiler (it won't take much) and let it boil. The smell should go to wherever there is a leak. Including the units that they won't let you in. The smell will come under the doors and you will smell it somewhere in the building. Then, there's dye. It would seem to me that the loss isn't in the steam, its in the water. Sometimes, we plumbers or water companies get calls for excessively high water bills. Water providers have vast computerized records. They can print out and locate patterns of use for you. Sometimes, it is leaking toilets that cause problems. They have special high test dye that you put in toilets and look for the dyed water in the sewers. If there are floor cleanouts, you can look in those for colored water. If you can't see beyond a Wye, use a portable camera. Cheap. If you put dye in the boiler, and it is being pushed out the return, you should find signs of the dye if someone drained it in to the sewer.

I found that when using my True Spot Smoke Tester, if there was a lot of moisture in the exhaust, the paper came out all wet or damp if there was too much condensation.

Another thing. With the water use, I assume that the feed water is shut down once it warms up and the boilers aren't running. If the feeds are on, there must not be any flow or usage. But, looking at the monthly records, can you "adjust" the water usage to be consistent throughout a year or does it increase when the boiler comes on or go off? If it was oil, most oil companies have sophisticated computer systems that can give you all kinds of useless information that can be useful.

Don't be afraid to use air. My small, portable nail gun air compressor, set to 10# or 12# will locate any leak in the system. All you need to do is listen. If your hearing is bad, get help. If you have a hissing air vent, remove it.

I've seen this.

A Weil-McLain 78 Series boiler uses gaskets to seal between sections. They are absolutely emphatic that you DO NOT!!! Put ANY RTV Silicone on the gaskets or the surfaces they go against. The #72, 1990 vintage boilers had only a stop ring cast into the sections on the OUTSIDE, the thought was that the pressure was always OUTWARD. But if someone put RTV on the gasket or surface, when the sections were pulled together, the gasket wanted to slide somewhere and because there was no inside stop. So, the gasket could slide inside and cause a leak. I saw a boiler run for 9 years like this. It wasn't until I dis-assembled it that I found all these leaking gaskets. The later boilers have the inside shoulder. If the former installer did as quality a job as you describe, he certainly didn't read the I/O manual for detail. And if he did, and noticed that part about the RTV and the gaskets, he was probably smarter than the engineers that wrote the I/O manual. The RTV goes on the outside machined shoulder to keep exhaust gasses INSIDE the boiler block. Not to keep water inside the block.

Because it is not common to do a smoke test on a gas boiler, you might have high humidity in the flue has as it leaves the boiler. Check the exhaust with an oil burner smoke tester and see if you can see any humidity on the paper. It will be obvious.

FWIW.