P29NC is a low pressure control with time delay and lockout, which requires manual reset.  A drop in pressure energizes the time delay relay and opens a contact after 60 secs. shutting down the equipment.  The time delay prevents nuisance shutdowns due to momentary fluctuations in system pressures. 

Specifications

• Switch Action: SPST
• Presssure Range: 20 in. HG Vacuum to 100 psi (-68 to 690 kPa)
• Differential: 2.2 - 1.5 psi, 15.2 - 10.3 kPa
• Max. Overpressure: 325 psig, 2241 kPa
• Max. Working Pressure: 250 psig, 1723 kPa
• Pressure Connection: 1/4" male flare fitting
• Time Delay Setting: 60 seconds (factory set)