The leak detection job from hell — Pt. 2

This month’s column is a continuation of my May column about a mysterious leak in a condo complex. Read on to find out more about the mystery...

There was a unit right next to this unit (the one consistently at 80°F) that also had elevated temperatures (75°F), and it had recently had its floor jack hammered up by someone else attempting to find this rogue leak. Did I mention that this process had been going on for numerous years? Well, that jackhammer surgery session was a waste of time because the floor beneath was bone dry. But I had to perform due diligence, and determine why this unit was so hot. I attempted to perform a hydrostatic test on the lines because there was isolation gate valves on the supply and return lines serving this unit, and a drain valve to access the line pressure. One slight problem: The isolation gate valves had been affected by the continuous flow of makeup water, and would not hold pressure. So much for hydrostatic testing...

We ended up having to drain the building and install new ball valves in order to get good isolation on this suspect part of the system. The preliminary test that we performed after the installation of two 3/4” ball valves proved that the piping between the valves had not been breached in this unit. The reason for the unit overheating was that the zone valve was not closing off completely, possibly due to a hardened ball in the zone valve or possibly a bypass being caused by the recently replaced circulator.

Extra sleuthing

We replaced the zone valve, and temperature did reduce some, but it would not cool down completely, indicating that there was bypass occurring. We verified this by closing off one supply ball valve, and determined that it was in fact bypassing due to the oversized circulator. A check of the three speed circulator found that it was being operated on the highest speed. At this point, I had to do some extra sleuthing, because the original circulator was nowhere to be found. I went to another boiler room serving another part of the complex and found the original circulator. It was a three piece circulator typical of pumps being used during the era that the original system was built. A comparison of performance curves found that even on low speed, the new circulator was capable of generating enough pressure to cause the zone valves to bypass, and there was no pressure activated bypass in the mechanical room. Hence another “issue” to throw a monkey wrench into my sleuthing.

As I told my associate, who got me involved in the first place, I have had many years of dealing with these board of directors for Home Owners Associations (HOA), and have found in all cases, that none of the board members want to make a decision about the physical plant, especially when expenditures are involved, and none of these associations ever has any money to spend in the first place. Therefore I was reluctance to get involved, but these people were desperate, and I love a challenge. I knew that my recommendation to either replace the circulator with a properly sized circulator, or install a properly set pressure activated bypass valve would fall on deaf, nearly bankrupt ears. Yet, I had to charge onward. There was still water running out of the electrical conduit on the far end of the complex. I created my own non-pressure activated bypass in the mechanical room in an effort to alleviate the bypassing zone valves in an effort to keep moving forward.

During our investigation, we had to access all of the lower garden level apartments in the suspect building. We asked the HOA to get notifications out to the residents, telling them that it was critical that we be allowed access to their units, and that the floors needed to be completely free of all items, including mattresses, bedding, clothing etc. This is a requirement in order to perform a no pump forced flow infrared survey in our efforts to find any suspect hot spots in the floors of the living units. When we showed up to do the no-flow, hot pressurized infrared survey, we were faced with units that were locked with no access, and when we finally did achieve access, we found floors completely covered with items that make it virtually impossible to perform an infrared imaging inspection.

We wasted a lot of time and effort, and decided that if it was going to be necessary to do this in the future that we would take the initiative to do this foot work ourselves to insure that everyone understood the details and requirements. In some cases, the residents claimed that they had not been notified. And in some cases, there was miscommunications as to the times and dates of our inspections.

Tune in next month as we continue our search for the elusive leak. Until then, happy hydronic leak busting!

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