User Guide

Construction details
AutoFill™,
code 553642A
Backflow preventer,
code 573403A
Filter housing, code NA573100, with
demineralizing cartridge, code NA573102
Isolation ball valves
Most closed-loop hydronic systems lose small amounts of water and air over time. These losses
come from automatic air purging of dirt separators, weepage at air vents, valve packings or
circulator flange gaskets. Fluid loss also occurs when a component such as a circulator is replaced.
Over time, a standard make-up water assembly would allow untreated water to enter a system as
demineralized water is lost. If the system was filled with treated demineralized when commissioned,
untreated make-up water could bring undesirable compounds, such as calcium carbonate, back into
the system. To prevent this, Caleffi offers an enhanced assembly, code NA573022, that includes a
demineralizer cartridge. This is a replenishment water treatment assembly consisting of a backflow
preventer and a pre-adjustable automatic filling valve with pressure gauge used to automatically
feed small quantities of demineralized water into the system. This assembly is shown above. This
unit would be installed, of course, after initially filling the system with the Caleffi NA570 series
HYDROFILL™ portable water treatment filling unit.
This assembly uses a special 10-inch demineralizing filter cartridge, code NA573102, containing
the color changing resin beads necessary to demineralize water passing through it at relatively
low flow rates. The cartridge assembly can be isolated by closing the two ball valves. The clear
housing can then be unscrewed to remove and replace the cartridge. The Caleffi cartridge will
appear blue color when new. Its internal color will change to amber as the resin beads approach
a spent condition. Each cartridge can demineralize approximately 30 gallons of water at 180 ppm
of untreated water. This should provide several years of normal make-up water supply, assuming
only minor water losses from the system occur.