Wiring a square D class 9016 GAW-21 vacuum switch to control my 240V vacuum pump

I am confused as to how to wire my vacuum pump to this vacuum switch.  The pump is 240 V single phase and I need it to come on at about 22 inches of mercury and shut off at about 28 inches of mercury.  I have two line leads coming from the pump that need to be switched.  I don't understand the diagram (first picture) that covers the connection terminals.  I think if I can get it wired properly I can set the on/off points using my vacuum gauge and trial/error.  Can anyone help me with this?

Picture of Wiring a square D class 9016 GAW-21 vacuum switch to control my 240V vacuum pump
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Aerospaced3 years ago
Ok, here we go.
Lets start at the top end.
Terminals 1,2,5 and 6 are your high end shut off points. 1&2 for the LINE 5&6, for the NEUTRAL.
Terminals 3,4,7 and 8 are for the low end turn on points. 3&4 for the LINE, 7&8 for the NEUTRAL.
NOTE THE STATEMENT ON THE LABEL OF " SAME POLARITY" . Your line (1,2,5 and 6 ) should be kept to one side and the neutral (3,4,7 and 8 ) to the other.
You can test the states of each contact with a continuity meter in the following manner with out applying power through the switch itself.
3,4,7&8 show to be normally closed. This will be true at ambient pressure. Probe between 3&4, you should get a "ring" on your meter. Repeat on terminals 7&8.
Next, dial down you trip point to its lowest limit. Place probes between 1&2, there should be NO CONNECTION YET, then use your pump (connected to a power strip with a switch on it) to draw a vacuum on the sensor port of the device. Your meter will ring once the proper vacuum is drawn. Repeat for 5&6.


I am trying to do the same thing and am confused about the term NEUTRAL on 220 single phase. I believe I have two hot or LINEs and no NEUTRAL. Some diagrams show a combined GROUND/NEUTRAL. Should I use a combined NEUTRAL or have hot LINEs going to each side while ensuring the same polarity.