On Thu, 14 Jun 2007 19:30:19 -0400, Nate Nagel
wrote:


As I understand it, it's not actually inside the tank, but wrapped
around the tank but inside the outer sheetmetal shell in a long spiral.
Of course, I can't state this with 100% certainty as I haven't removed
it and cut it apart yet.

As an aside, but a related one - how does one "charge" the heat transfer
fluid? It appears to be pressurized to about 20 PSI.

Is that because the pump is running?

Other than that, I think there is no way to pressurize antifreeze
(which would only expand a tiny bit), but if you make everything real
hot, you can pressurize the air in the tubing, like in a car's cooling
system. I don't see any advantage to it being pressurized since I
don't think it reaches the boiling point. The purpose of pressuring
the car's cooling system is to raise the boiling point. At any rate,
if it's sealed, the pressure will increase as the temp goes up.

nate