Reply to "Overflow tank"

some more of my thoughts...

with the 14" tank plumbed like picture #2, and the tops of the expansion and swirl at the same elevation, when the pump stops there will be a path so that the water level in a partially filled expansion will equalize with the swirl, thus the level in the swirl will go down and the expansion go up.

If I should go with partially filled configuration, I would try to raise the top of the expansion about 7" above the top of the swirl. thus if I filled the swirl, it will fill the expansion to the same elevation.

the reason for the swirl tank is to remove air from the circulating coolant. taking the seperation of coolant and air farther would be to eleminate any pressurized air and coolant boundary by completely filling the expansion tank like picture #3. with this configuration, the elevation between the swirl and expansion can have both tops the same.

another consideration between the partial filled or the full filled expansion tank would be the rate of pressurizing the coolant as tempertue increases. with a full tank, the pressure quickly goes to the cap rating (15psig shown). If the expansion tank is not filled exactly to the correct level the coolant pressure will not reach cap rating.

I am thinking picture #3 will be my choice