Misleading and sometimes incorrect statements regarding how to select and pipe expansion tanks can be found in design manuals and manufacturers' installation guides. Some of the more common claims follow. Claim: Expansion tanks must be connected to the system near the suction of the pump. Fact: Closed expansion tanks (those not vented to the atmosphere) may be connected anywhere in the system provided their precharge (initial) pressure and size are correctly selected. However, maximum pressure ratings of some system components may limit expansion tank connection location.