Work from the outside in:
- Leaks in piping, flanges or valves — perform a pressure-rise test first
- Blocked inlet filter or exhaust filter
- Emulsified or degraded oil, or low oil level
- Worn seals, rotor or vanes
- Gas too hot, too humid or heavily loaded with dust
- Gas ballast or check valve not working correctly
Most low-vacuum complaints trace back to leaks or oil condition — check those before stripping the pump.
