Why can't I reach or hold my target vacuum?

Let’s check these possibilities.

• Cold trap first — if it is saturated or not cold enough, solvent vapour passes straight to the pump and seriously limits achievable vacuum.
• Seals and joints — inspect every elastomer seal, ground joint and hose connection with a leak test, since a single hardened O-ring will defeat an otherwise tight system.
• The pump itself — degraded or contaminated oil, a worn vane set or an undersized pump at your actual operating temperature will all reduce performance.
• The material — moisture, light solvents or dissolved gas in the feed outgas under vacuum and must be removed by degassing or pre-treatment.

Most “vacuum faults” resolve at the cold trap or the seals.