Shleprock
New Member
I have an 1860's stone home with a gas fired boiler force feeding cast iron radiators on three floors. There are two zones controlling cast iron radiators and one zone controlling a PEX loop installed in joist bays under my kitchen floor. I am trying to solve cavitation on the main boiler circulator whenever heat is called for only for the PEX loop. This is a common condition as the kitchen has no cellar underneath and the area is less insulated..so the one zone that is almost always on is this floor loop. The hydronic PEX loop has its own circulator (Grunfos 1/25 hp which is how it is controlled via thermostat), but the main circulator also runs when this loop is on only...and cavitates...and there is no zone valve on this loop. Is the restricted flow (the other zones being closed) and the taco 1/25 hp forcing 180F through 1/2" PEX causing the cavitation? My concern with lowering the cut on temp of the PEX loop is possible freezing in the line...Just looking for some suggestions..thanks!