The sniffer piston can be very tricky and frustrating to set. First thing is get 500 sheets of your best sheet hopefully around 80#, front and back trimmed. Feed sheets at 3000 iph. Once the sheet gets to the storage drum you should see the pin on the left side of the piston box push out, depressing the microswitch. As you increase speed you will see that this pin gets a little movement in it, the faster you go the more movement. The trick is to get the switch adjusted in a position where it will let you run at high speeds but also still detect a "actual" dropped sheet. You will have to experiment with the switch. Final test is take 1 sheet from your 500 and trim 2 more mm off the length of the sheet. Mark this sheet with a huge black X and place it 20 or 30 sheets into your pile. Run your press at your desired speed and the press should detect this "X" sheet as dropped. If this does not happen your switch has been adjusted too close to the piston box. While you should be able to run at a speed of higher than 7000 iph, you may not be able to run at full speed. Bear in mind too that it also could be a vacume leak somewhere in the plumbing of your storage drum. I would make sure your suction pump is sucking properly and the filter in it is good. Make sure the hoses from the pump to the piston are good. Make sure the hosed from the piston to the storage drom are good. It is possible (but unlikely) that the turning valve may be bad too. You should also check the suction cut off time too. This is the time that the tail suckers let go of the sheet. This is very easily adjusted. As you inch the press and look down between the storage drum and side frame you will see a post sticking out of the storage drum. The top of the post closest to you is between 2 pins sticking out of the storage drum. These two pins are welded to a plate which is bolted to the drum. This plate has slotted holes which allow you to slide the plate forward or back, moving the post forward or back, by doing this you can either lenthen or shorted the time the suckers hold the sheet. Best way to check this is mark the current position of the plate so you can move it back to its original position if needed. Than move it all the way forward and feed sheets, move it all the way back and feed sheets, if you notice improvement in either position you will need to adjust suction cut off time and you will need a degree value for this. I might be able to help you with getting a degree value if you need it.
