Why is there white smoke coming from the exhaust fitting
The “smoke” that is coming out of your pump is actually oil vapor mist.  It is normal for a small amount of oil vapor mist to come out of a pumps exhaust while the pump is pulling a chamber down to its ultimate vacuum. Most customers never see this happen as their pump exhaust may be piped out of building or they may have an exhaust mist eliminator attached to the pump.  The vapor mist should subside to almost nothing once the ultimate vacuum is achieved. If it does not, then there may be a vacuum leak at some point in the system or within the pump itself. The simplest explanation is air in, air out. Make sure all of the pump connections are clean and snug. If possible, blank off the pump inlet and see if the vapor mist subsides. This will eliminate the vacuum pump as the possible source of the problem.  If the problem persists, please contact one of our sales engineers for more information.