Module 06 — Pumping Systems & Maintenance | VacTech Fundamentals | Shop-Floor Reference
| Check Item | What to Look For | Pass / Warning / Fail Criteria |
|---|---|---|
| Oil Level Daily |
View the oil sight glass with pump running. Oil should be between the MIN and MAX marks. |
PASS: Level between MIN and MAX
WARN: At or near MIN line
FAIL: Below MIN or not visible — stop pump, top up
|
| Oil Colour Weekly |
Compare against fresh oil sample. Should be clear amber/golden. Dark or milky oil indicates contamination. |
PASS: Clear amber, transparent
WARN: Darkening — schedule oil change
FAIL: Black, milky, or particulate — change immediately
|
| Ultimate Pressure Monthly |
Blank off the inlet and measure base pressure after 30 min pump-down. Compare to manufacturer spec. |
PASS: Within 2× manufacturer spec
WARN: 2–5× spec — check oil, gas ballast, seals
FAIL: >5× spec — service required
|
| Noise & Vibration Daily |
Listen for unusual knocking, rattling, or grinding. Feel for excessive vibration at the pump body. |
PASS: Smooth, steady hum
WARN: Intermittent clicks or increased vibration
FAIL: Grinding, knocking, or seizure sounds — stop pump
|
| Exhaust Filter Monthly |
Check oil mist eliminator for blockage or oil bypass. Inspect exhaust for visible oil mist. |
PASS: No visible mist, filter clean
WARN: Slight mist visible — replace filter element
FAIL: Heavy oil mist in exhaust — replace immediately, check for backpressure
|
| Check Item | What to Look For | Pass / Warning / Fail Criteria |
|---|---|---|
| Tip Seal Wear Quarterly |
Track hours since last tip seal replacement. Manufacturer typically recommends replacement every ~10,000 operating hours. Check for increased base pressure as a proxy for seal wear. |
PASS: <8,000 hrs since replacement, base pressure nominal
WARN: 8,000–10,000 hrs or base pressure rising
FAIL: >10,000 hrs or base pressure >3× spec — replace tip seals
|
| Base Pressure Trend Monthly |
Record blanked-off base pressure monthly. Plot trend over time. A gradual rise indicates tip seal wear. |
PASS: Stable within 50% of commissioning value
WARN: Rising trend >50% above baseline
FAIL: >3× baseline — tip seal replacement due
|
| Noise Daily |
Listen for scraping, clicking, or irregular rhythm. Scroll pumps should produce a smooth, quiet whirr. |
PASS: Quiet, smooth operation
WARN: Slight clicking or increased volume
FAIL: Scraping or grinding — stop pump, inspect scrolls
|
| Check Item | What to Look For | Pass / Warning / Fail Criteria |
|---|---|---|
| Spin-Up Time Each start |
Time from start command to full rated speed. Compare to commissioning baseline. Increasing spin-up time indicates bearing degradation. |
PASS: Within 10% of commissioning time
WARN: 10–25% longer than baseline
FAIL: >25% longer or fails to reach full speed — bearing service due
|
| Vibration Weekly |
Check controller vibration readout if available. Alternatively, place a hand on the pump body — a healthy turbo should feel nearly vibration-free at full speed. |
PASS: No perceptible vibration, controller reads nominal
WARN: Slight vibration detectable or controller warning
FAIL: Audible vibration or controller alarm — stop pump, suspect rotor imbalance or bearing wear
|
| Bearing Temperature Continuous / Daily |
Read from pump controller. Normal range depends on pump model (typically 40–60 °C). Rising temperatures indicate bearing degradation or insufficient cooling. |
PASS: Within manufacturer’s normal range
WARN: Approaching upper limit or trend rising
FAIL: Exceeds limit — controller may auto-shut-down; investigate cooling and bearing condition
|
| Purge Gas Flow Daily (if equipped) |
Verify purge gas (dry N2) is flowing at the specified rate. Purge protects bearings from process gas ingress. |
PASS: Flow rate at set point (±10%)
WARN: Flow reduced or supply pressure low
FAIL: No flow — bearing damage risk; check supply line and regulator
|
| Check Item | What to Look For | Pass / Warning / Fail Criteria |
|---|---|---|
| Foreline Pressure Continuous |
Monitor foreline (backing) pressure between roughing pump and turbo. Must stay below turbo’s maximum foreline pressure (typically <10 mbar). |
PASS: <5 mbar (typical)
WARN: 5–10 mbar — check roughing pump performance
FAIL: >10 mbar — turbo at risk; check roughing pump, foreline for leaks or blockage
|
| Backing Pump Coordination Each start-up |
Verify backing pump starts before turbo and remains running while turbo is spinning. Turbo must never operate without adequate backing. |
PASS: Backing pump running, foreline pressure below threshold before turbo start
FAIL: Turbo started without backing pump — shut down turbo immediately
|
| Cooling Water Daily (if water-cooled) |
Check cooling water flow rate and temperature at inlet/outlet. Verify no leaks at hose connections. |
PASS: Flow nominal, ΔT <15 °C, no leaks
WARN: Reduced flow or ΔT rising
FAIL: No flow or visible leak — shut down cooled components, investigate
|