The pressure swtich (40/60 psi Square D switch)on my well pump was turning on and cutting off rapidly. I replaced it with a new one and it worked ok for about 2 days. Now the new switch is doing the same. If I bipass the switch the well runs great, so something must be wrong with the switch. I am the one that installed the last switch and it worked well for 5-6 years. I installed it the new switch the same way. I don't know why this stich keeps turning on and off. Any Ideas???