Vacuum packaging machines use after a period of time, may not work, if there are several reasons for this reference;
1, power supply problem caused by vacuum packaging machines do not work (check lines),
2, limit switch broken switch or limit switch paddles touch the trip caused a vacuum packaging machine sometimes work sometimes not working, (this is the most common)
3, the valve will not open will create a vacuum packaging machines do not work, (the valve is bad, or the valve is not powered up),
Phase 4, vacuum pump, or fails (read carefully pump instructions).