Back Pressure Transducer Valve

1. Connect vacuum pump to two uppermost ports one at a time and check them for leakage.
2. When vacuum is applied to uppermost port and port immediately below that is open to atmosphere, uppermost port should open at 2.36 inches Hg.
3. When vacuum is applied to top two ports, they should both open at 19.69 inches Hg.
4. When two uppermost ports are open to atmosphere, valve should be closed.
5. If valve does not operate as described above, it should be replaced.