water expansion tank

[Lc_shi]

we usually install the expansion tank at return pipe of system pump. is there any concern if install at output of the pump?

[botrous]

Is it an expansion tank for a heating system . eg boiler ???

[Brian_UK]

If it is an open vented system then ideally the tank should be connected at the neutral point as regards pressure.

[RogGoetsch]

we usually install the expansion tank at return pipe of system pump. is there any concern if install at output of the pump?

The expansion tank provides a constant pressure point in the system. When operating, the pump pressure rise equals the total system pressure drop. If the expansion tank is placed at the pump intake, it provides a constant pressure at the pump suction and the pump pressure rise is added to the static value.

If placed at the discharge of the pump, it will maintain its static value at that point and the pump suction presssure will drop in relation to the static value. The potential harm is in cavitation at the impeller due to low pressure. Cavitation damages impellers.

Rog

[Lc_shi]

professional answer！ very good. thx indeed.

[shogun7]

The expansion tank provides a constant pressure point in the system. When operating, the pump pressure rise equals the total system pressure drop. If the expansion tank is placed at the pump intake, it provides a constant pressure at the pump suction and the pump pressure rise is added to the static value.


Rog

This is also known as the point of no pressure change