Hi ,
I have experiencing HP switch (cartridge type) erratic tripping issue with our AC units. This switch is Schrader pin type and has a cut out pressure of 30 bar. When we tested the unit by partially blocking the condenser , the HP switch initially tripped at 445 psig and reset at 300 psig then tripped at 350 , 270 psig. The switch was installed in a liquid line after condenser. What would be the problem? It is happening almost in all the units

Regards,
sendhil