A reduced pressure treatment apparatus includes a charging chamber storing a first pressure less than an ambient pressure and a regulated chamber storing a second pressure less than the ambient pressure. The first pressure is less than the second pressure. A conduit provides fluid communication between the regulated chamber and the charging chamber. A regulator member is operably associated with the conduit to prevent fluid communication through the conduit when the second pressure is less than or equal to a desired therapy pressure and to allow fluid communication through the conduit when the second pressure exceeds the desired therapy pressure.