Happy 4th everyone!
I would appreciate your advice please. I'm re-piping my chilled-water AC system (Spacepak) this weekend to improve performance - I'm installing a Heat-Flo buffer tank in the attic with short, fat 2" headers for the secondary supply and return. I chose this tank as it fits vertically in the limited space available. Before I make the final connections, I wanted to run this past The Wall.
My concern is with the primary loop. Most of what I've read recommends the cold supply from the chiller to be connected to the bottom port, and the secondary loop supply header to be placed directly across from it for laminar flow. On this tank, there are four 1 1/4" ports - two on the left, one on the right aligned with the bottom port on the left, and one out the top of the tank. I'm assuming the chiller return should come off the top of the tank, with the SpiroVent and expansion tank at the high point. I plan to bring that line horizontally into the SpiroVent, then exit into a 45 toward the attic floor, leveling off with another 45 and then into the primary loop pump (pump A). The pump is pumping away from the expansion tank, and is about 22" lower than the pipe exiting the tank.Do I need to worry about pump cavitation with this arrangement
? The pump is a Taco 2400-50, sized for the higher head of the chiller (21' @ 12 GPM) and the 1" pex for anything that is not 1" copper. If there is any air in the system, it should be in the pipe at the top of the tank and ultimately will be removed by the vent when I perform the final top-off. I run a 30% Prop. Glycol solution and I monitor the pressure - about 20lbs at rest. I don't have a water-makeup system - I add solution if the pressure drops - it doesn't really ever lose fluid.
The attached diagram shows the relationship of the components. The chiller is out-of-doors at ground level -single story house.