Video: How does the M4 option on a 9013 F limit switch work?
9013 Pumptrol pressure switches
The M4 option includes a low pressure cut off, available only on standard action switches. It is not available on reverse action, where contacts open on falling pressure.
When the pressure drops 10 psi below the cut in setting, the switch will move to a maintained OFF position.
To reset the switch, move the selector lever to Start and hold the lever in the Start position until pressure in the system rises above the low pressure cut off point. Release the lever to Auto and the 9013F will then revert to an automatic cycling of the contacts, as long as the pressure remains above the low pressure cut out.
There is NO automatic way to exit the low pressure cut off. The lever is spring loaded in the Start position and must be held against spring pressure to allow the system pressure to build above the cut off point. Auto and Off are maintained positions.
The low pressure cut off is a fixed 10 psi below the cut-in range of the switch, and will follow as that value is adjusted up or down. Also, if the system pressure is restored from some outside source, the lever must still be manually moved from Off to Auto to allow operation of the contacts to resume.
On initial installation, after applying power to the system, the lever must be held to the start position until pressure builds to within 10 psi of cut in.