the surging you are experiencing I think may be caused by the condenser. the style of condenser you have needs a fairly high flow rate to cool properly, so you are most likely having very cold water hitting very hot vapor, this will create a vacuum/pressure cycle that while similar to "chuffing" has a much longer cycle time
as for solutions,turn down your water flow to the condenser till it stops, your distillate will probably come out hot if left like this, but turn the cooling water up slowly till you find a point of equilibrium between surging and warm distillate. On a larger system suffering from this same issue, a vacuum break can be added to the top of condenser.
one other more costly option would be to swap out your condenser for a more efficient inverted flow multi tube condenser, if you are not recirculating your cooling water, this will save you a lot of water down the drain.