A major air leak can prevent the pressure levels from being low enough to turn on the system. Possible causes of a major leak might be a loose or disconnected fitting, an improperly positioned O-ring, or an open valve.
Procedure
- Listen for a rush of air or a hissing sound coming from the MS.
- If you do not hear these sounds, there is no air leak.
- If you hear these sounds, continue with step 2.
- Shut down the MS for service. See Shut down the MS system completely for planned service or storage.
- Visually inspect the vacuum system and vacuum lines for leaks.
- Check each fitting and flange on the system for tightness, and tighten any that are loose. Start with fittings that have been changed recently and fittings that have been subjected to heating and cooling.