Leak in church hot water heating system with inaccessible piping.

Here is a "rough" sketch of the piping showing the arrangement in the boiler room. Lots of question marks and no markings of which return is for which pump. I wasn't familiar with the method of maintaining the temperature in the system, but got some help understanding that the boiler pump recirculates the hot water and the individual loop pumps supply water to the registers. Only one of the circulating pumps has any key to what it serves (it's the one marked sanctuary). I'm not sure of the path of the hot water lines to the faucets in that part of the building.

Since I wrote the initial post, I was informed the trustees had a plumber come who was able to identify which loop is affected by tracing the sound. The "good" news is that the loop feeds some rooms not that far away and underground piping may not be all that extensive. But it does go up to second floor spaces.

I appreciate the comments and will look into the comment about the hot water liner.

In my conversations yesterday with a couple of the trustees, I did mention the possibility/probability of future leaks in the system. Abandoning the loop and installing replacement piping, etc. to provide all existing functions will be a challenge, both physically and financially. Since this is a church, I'm not sure if it is allowable by code to eliminate the hot water to the faucets served by this loop.

You caught me with my foot in my mouth…not the first time on HH. I know better, the truth was hidden among all the other truths hiding deep in my mind, waiting for a time to be exposed.

I think I had messed up thinking the two tapoffs just before the left red and sanctuary pump loops are hot water. But like @Jamie Hall said that's not likely. I have no idea what they could serve.

Also a hot water heater is in the same room, so I can prove myself wrong by tracing its hot water line out of the room.

None of the boiler room floor openings have any water in them. I will check into that.

@Mad Dog_2 The trustees did just what you said. When the trustees couldn't positively identify which loop is leaking, they got an experienced plumber to troubleshoot. He was able to determine the leaking loop and fortunately the valves in the loop don't leak. That loop is now isolated, and the rest of the system is fine (who knows for how long as mentioned earlier in this discussion by many of us).

Their plan is to eliminate use of that loop and establish a different heating system for that section of the building. Hopefully it won't be too horribly expensive.

Thanks to all for their comments.

I agree a large amount of makeup isn't the greatest thing, especially at 1 gallon a minute (1440 gallons per day). At the same rate as I pay for my house ($45.02 for 8186 gallons = $0.0055) which is walking distance from the church, that amount of leakage would cost $8 per day ($0.0055*1440 = $7.92).

Since the church is not occupied 24/7, the intent of the water meter is to be an easily monitored indicator of a leak. Unlike steam systems, hot water systems shouldn't consume water. Depending on the nature of any inevitable leak, the scenario that happened can be repeated. No one knows when or where the next will occur. The way the trustees found out about the leak is from the quarterly water bill from the town. The leak started in January, increased substantially in early March and was not found out until they got the water bill in April.

I agree installing a water meter is questionable, but given the history of the system (radiant heat failures years ago, current failure), the cost for a meter is inconsequential compared to the cost of leaked water even at much lower leakage rates. Installation cost is minimal. Additionally, no one knows what the effect of the current leak has on the ground below the building.

Installing it acknowledges the reality of a future possibility and accepts that another can/will eventually occur. I look at it as a preventive measure to ensure what just occurred won't be as extensive in the future. Abandoning and substituting something different for all of the current system is cost prohibitive.

I don't know if the other system has ever had a leak. I will look into it.

Once the current leak is removed from the system, it is a good idea to do a followup leak check to see if pressure is maintained in the system. There is an expansion tank in the system and temperature change in the system can mask a leak. These will have to be taken into consideration to get the truth. It's somewhat like leak testing an underground fuel tank.

Tell me more about Fernox. Treating the water seems worthwhile.

So, here's the next question, even though some believe the idea is a waste of money.

Instead of a totalizing water meter, is there a device that can send a signal to the internet when an add of water to the system occurs?

A couple of decades ago, when I was on the board of directors of a senior citizen complex that had auctioneered pumps for the septic system, the only way to tell if an alarm occurred was if the folks living nearest the system could hear the alarm. When we did an upgrade of the system, we had an alarm added that fed the fire alarm system notification setup. That way there was notice 24/7 of the occurrence.

I wonder what might be available to monitor makeup water in the system that has underground piping and some history of leaks.

Here's the update. Yes, the leaking loop has been identified and isolated. Plans are being developed to provide a different source of heating to the affected area. With the warm weather, heating will not be an issue and hopefully the plan can be formulated and executed before the next heating season.

The subject of monitoring makeup water is to acknowledge the history and future possibility of another leak and to be able to "find" it by some means other than a quarterly water bill. The building already has some leak detectors in several rooms, but I don't know if they are just local or connected to the monitoring system.

Here's a small world side story. Yesterday, I went to the church to look for whatever may exist for a monitoring system. There is one and I found the name of the company that does any service. A few hours later, I was blowing the grass clippings off the sidewalk in front of my rental and one of the company's service trucks came down a side street across from the house. I waved the guy down and had a good discussion with him and he said he is pretty sure they can handle the situation. What a coincidence!!!!

If the trustees decide to do something, there are at least these choices:

Install a local reading water meter and take periodic readings. Someone would have to be appointed to take the readings. This is probably the least expensive option.

Install a locally "alarming" device.

Install a device that can connect to the existing monitoring system. This is probably the most expensive option, but gives 24/7 surveillance of the condition of the system and does not require any direct action on a routine basis.

One technical consideration is to identify equipment that will be able to identify the leak at a reasonably low level of leakage.

Obviously this concept is primarily for undetectable leaks in the system and can be a warning for small ones that become visible.

Obvious idea. One of my considerations in setting up a logging system is how long before it tells us something is going on. If nothing happens for "years" it might fall into disuse.

I was informed yesterday there are temperature sensors attached to the monitoring system, but do not know where they are located. I'll look into that. Assuming it already would provide enough warning it's easier than the wacky scheme I have been dreaming up.

More to follow.