That is a good question. Mudduck had purchased one of these, and gave me some info on your type. It seems that this was one of the very first Vacupack models ever produced. Evdentaly this was a no frills machine that does not have the current improvements with the removable bottom plug, or the time adjustable bag sealer. Also from what mudduck said (who was informed by the P.M.G. guy) was that the unit nozzle can be removed via a screw at the bottom. Mudduck also conveyed to me that there seems to be a small hole on the right side, that may have an adjustment with a jewelers screwdriver to adjust the time cycle of the sealer.
Mudduck won one of these on E-Bay, but sent it back,as he didn't want to be bothered with the hassle of the bag sealer. I would check with P.M.G as E-rain stated for advice on servicing and procedeure. I think your machine is ok, just a little more primative than the newer units.
Dennis