To keep an Edwards E2M or E2S two-stage rotary vane pump performing at its rated ultimate vacuum of about 2×10-3 mbar, do three things: change the oil when it darkens (using Edwards Ultragrade Performance 19), keep the gas ballast closed except when pumping vapour, and have the pump serviced (vanes, seals and tip seals) when performance drops. Girovac is an authorised Edwards distributor and services these pumps in our workshop.
About the E2M and E2S
The E2M and its successor the E2S are two-stage, oil-sealed rotary vane pumps — reliable workhorses for laboratory vacuum, freeze-drying and backing turbomolecular pumps. The E2S is available in nominal 5 and 12 m3/h pumping speeds and reaches an ultimate total pressure of 2×10-3 mbar without gas ballast.
Oil: Edwards Ultragrade Performance 19
These pumps use Edwards Ultragrade Performance 19 mineral oil. Check the level and colour through the sight glass; change it as soon as the oil darkens, goes cloudy or the vacuum drops — see how often to change vacuum pump oil. Warm the pump first, drain fully, refill to the mark, and don’t overfill (overfilling causes oil to leak from the exhaust).
Using the gas ballast
The E2S gas ballast has three positions — closed (0) and two open settings (I and II). Open it when pumping water or solvent vapour to protect the oil, and close it for dry running to reach the deepest vacuum. Learn more about gas ballast. A solenoid valve is available for automatic control.
Routine checks
- Oil level and colour at the sight glass (weekly).
- Ultimate vacuum — if it won’t reach ~2×10-3 mbar, start with this troubleshooting guide.
- Unusual noise or oil leaks.
Major service and reconditioning
When the vanes, seals or tip seals wear, the pump loses vacuum and a workshop service restores it. If the pump is tired, a full reconditioning — strip, rebuild with genuine parts and test — brings it back to its rated performance for a fraction of the cost of new. We hold genuine Edwards spares.
Need an Edwards E2M/E2S serviced, reconditioned or spared?
We’re an authorised Edwards distributor with genuine spares and workshop servicing. Email [email protected] or request a quote.
Frequently asked questions
What oil does an Edwards E2S vacuum pump use?
Edwards Ultragrade Performance 19 mineral oil. Change it when the oil darkens, goes cloudy or the pump loses vacuum, and fill only to the sight-glass mark.
What ultimate vacuum should an Edwards E2M or E2S reach?
About 2×10^-3 mbar (total pressure, without gas ballast). If it won’t reach this, check for leaks, oil condition, an open gas ballast or worn vanes and seals.
Can Edwards E2M pumps be reconditioned?
Yes. As a two-stage rotary vane pump with genuine spares available, the E2M/E2S can be stripped, rebuilt with new vanes, seals and bearings, and tested back to its rated ultimate vacuum.
Written by the Girovac technical team. Girovac Ltd has supplied and serviced industrial and laboratory vacuum equipment from its North Walsham workshop since 1983. Last updated: July 2026.