if the vacuum is sufficient but the switch remains open

you ensure continuous

this model is an "open enclosure" type (No Enclosure) intended for mounting inside an existing control panel or equipment housing

The calls from the thermostats remain active

making it suitable for high-temperature hydronic cycles and standard low-pressure steam environments

Johnson Controls P170AB-2 Pressure Control Els PW 17895 if the vacuum is sufficientThe Johnson Controls P170AB 2 is a heavy duty single pole single throw (SPST) low pressure control engineered for critical cycling and high pressure cutout applications. This industrial pressure switch operates with an open low action, featuring a versatile pressure range from 20" Hg to 100 psi. Designed for reliability in commercial refrigeration and HVAC systems, it handles non corrosive refrigerants including R 22, R 404A, and R 134a. The unit