The Johnson Controls P74FA-5C Differential Pressure Control; SPDT; F/Water SYS;DIFF 2#;SNAP ACT;1/4″F(SEE:EMSU-90-06.
Series P74 measures the pressure difference between two sources: supply lines and return lines. A change in differential pressure will reposition the switching mechanism to cause corrective action of the supplementary control equipment.
Features
- field-proven Pennswitch with a completely enclosed contact mechanism
- pressure differential setting is easily changed without removing the cover
Applications
- differential pressure sensing on chillers or water-cooled condensers
- lube oil failure cutout for refrigeration compressors (same as the P28, but does not incorporate time delay)
- positioning M100 Series motor-actuated valves (P74JA-2)
- to prove pump operation