Moisture detecting air cap indicator for expansion tank failure

A tank comprising:

• a housing defining a cavity and being formed of a material that corrodes and rusts when in contact with a pressurized fluid;
• a flexible member positioned within the cavity and connected to the inner wall of the housing, the flexible member separating the cavity into a first portion sealed to contain a pressurized gas and a second portion sealed to contain the pressurized fluid;
• an indicator connected to the housing in communication with the pressurized gas in the first portion of the cavity, the indicator including a cap having an inner end and an insert disposed within the cap, the cap being connected to an outer surface of the housing and including a transparent portion at least at the inner end, and the insert including a display portion that is a first color and that extends into and is spaced from the transparent portion of the cap to form with the cap an area for receiving the pressurized gas and/or fluid between the inner end and the display portion,
• wherein when the pressurized gas is free of the pressurized fluid, the first color of the insert is visible, and
• wherein when the pressurized gas includes a level of pressurized fluid that causes the material of the housing to corrode and rust, the pressurized fluid will be a second color visible through the transparent portion.

A tank comprising:

• a housing defining a cavity;
• a flexible member positioned within the cavity and connected to an inner wall of the housing, the flexible member separating the cavity into a first portion sealed to contain a pressurized gas and a second portion sealed to contain a pressurized fluid;
• an indicator connected to the housing in communication with the first portion of the cavity, wherein a first color is visible through the indicator when the pressurized gas has a level of moisture below a predetermined level, and a second color is visible through the indicator when the pressurized gas has a level of moisture at or above the pressurized level;
• and
• a valve at least partially enclosed by the indicator and in communication with the first portion of the cavity and the indicator such that pressurized gas expelled from the valve enters the indicator,
• wherein the valve includes a valve body connected to the indicator and a valve stem, and
• wherein the valve body includes threads on an outer surface thereof and the indicator includes threads on an inner surface thereof that mate with the threads on the valve body.