good morning,
I vacuum bagged 5 layers (1.7m x 0.500m) 650 carbon fibre.  I have a DVP EC.4 Compact Composites vacuum pump fitted with a SMC vacuum regulator and vacuum leak flow indicator.  The indicator showed there were no leaks in the bag. The pump ran for 9 hours and the timer shut it down.  When I arrived in the morning and disconnected the pump there was about 1cm of oil in the tubing between the pump and the regulator.  I can replace the tube, but would like to know if this is normal? (as it hasn't happened in the 20+ times I've used the pump previously) or is it indicating a problem? On your website it indicates that oil should not flow back into the tube. Any advice is appreciated.
As always, Thank you