Just thought i would share this with you, i have two of the smaller EC vac pumps and both have given me good service but i had noticed one was becoming very slow at pulling full vacuum. I decided to change the oil as it was due but noticed no difference in performance so i dismantled and inspected the vane pump and checked the valves and all was good. Whilst i had the pump body removed i opened the air valve and tried to blow through the valve only to find that air did NOT travel through it easily. I removed the valve to find a small gauze filter  partially blocked with resin, i removed the blockage and now the pump is as good as new. I do not recall the pump having sucked in any resin as i use catch pots but at some point it clearly had ingested a small amount.