quote:Rocky
The expansion tank should have a non-pressurized cap
Thats wrong, the Expension tank must have a pressurized cap, the overflow a non pressurized cap.
Simon[/quote]
Sorry Simon, Rocky is correct.
The two tanks are FOREVER being mis-named by owners. It makes these types of discussions very difficult and confusing when the same tank is called a different name by different people.
Please refer to the diagram posted in this thread by JFB.
The tall tank, the one that has the overflow hose that drains to the ground, does NOT use a pressured cap.
The shorter tank, the one that has the large diameter hoses at top and bottom, DOES need a pressure cap.
Larry