The GMP4’s primary function is to automatically supply pressurized water or a water/glycol mixture to a closed-loop space heating, chilled water, snowmelt, solar, radiant heating or process control system, to ensure that minimum system pressure levels are maintained. It features a 15 L (4 gal.) tank perfectly suited for mid-sized residential applications, and can be used for installations holding up to 300 L (79 gal.). Among its outstanding features are its rectangular design and compactness, meaning it occupies less space in occasionally cramped mechanical rooms. As well, it comes with its own wall-mount rack so the installer simply hangs the device at no further expense. The GMP4 is also equipped with an alarm floater so that users can hook up a sound alarm and be notified when liquid levels fall too low, a potential sign of leakage.