Loosing heating hot water

Mike Cash

I have a large school complex that does have some underground heating loops. on days that the heat has long off cylces, the system will loose approx. 13 cubic feet of water in two days, it does not leak when cool, or really working hard. There are no apperant leaks anywhere visible. It also has 2 vert. expansion tanks that seem to be slowly filling, but no water loss at tanks

Brad White_9

I think you know the answer.....

You have eliminated everything above ground as the location so yes, underground. Losing 2 GPH does not sound like much on a GPM basis, but seems realistic for a weeping joint. Expansion and contraction as you point out may be causing a joint to open up that otherwise would not when cool.

I would isolate the underground and pressure test it.

This will not get better and the new oxygenated water will start a downward cycle.

Unknown

did you?

Sounds like u have a very large boiler(s)... Wondering have you look inside the boiler, I had one leaky inside and doesn't show up as it was weeping into the floor cracks, etc..

Brad White_9

Good point

that the water may be evaporating into the combustion chamber.