Detecting Glycol Gloss in a Closed-Loop System

I would check my gauges. Provided there is no provisión for automatic makeup, the temperature gradient across de evaporator will decrease. Also, as the mass of recirculating liquid in the sistem decreases the recirculating pump discharge pressure will likewise decrease.

I'm not sure what temperature or pressure guages would accurately reveal. It's true that adding glycol changes pump curves, but certainly not to the extent that a casual observer could decide that glycol concentration has been reduced to the point of a freeze up. I'm sure there's expensive monitors.

How about a "low-tech" monitoring system? Cut in two TEES in the main line, one on each side of an elbow to create a small pressure drop, then install a boiler guage glass or a thinner glass tube with an outside diameter of a commonly available compression fitting, along with the acompanying isolation valves, to allow a trickle of free flow. Then break open a cheap anti-freeze tester, throw the balls in and you've got a reliable in-circuit guage to monitor concentration plus a "window" to see other pollutants.

TRY A HYGROMETER

I may be wrong, but if you have a Glycol loss, won't the temperature on whatever you are using it to cool goes up?? If you see the temperature goes up significantly, then I would check to see if there's any problem with my coolant. Whether its loss of fluid, or plugged stainer, etc.

MidniteFighter