Sounds like the contact inside the float is stuck. It can be corroded and not letting the circuit open and that will keep the pump running. If it had been fine but just started doing this, that is what I'd check. If someone could have accidentally wired it incorrectly when they were trying to fix it, perhaps they accidentally bypassed the float switch and have it "running hot" all the time.
There is a Cherry-style microswitch inside of the housing that is magnetically operated by the vertical float and float-rod. After years of cycling on and off, the microswitch contacts eventually wear and weld closed which cause the pump to run constantly. This has happened to me twice. The switch is a Cherry D48X 21(8)-2HP-250VAC 1HP-125VAC. The switch assembly is made to only be replaced as a full assembly, but the switch can be carefully removed from the assembly and replaced.There is a Cherry-style microswitch inside of the housing that is magnetically operated by the vertical float and float-rod. After years of cycling on and off, the microswitch contacts eventually wear and weld closed which cause the pump to run constantly. This has happened to me twice. The switch is a Cherry D48X 21(8)-2HP-250VAC 1HP-125VAC. The switch assembly is made to only be replaced as a full assembly, but the switch can be carefully removed from the assembly and replaced.
Answers & Comments
Sounds like the contact inside the float is stuck. It can be corroded and not letting the circuit open and that will keep the pump running.
If it had been fine but just started doing this, that is what I'd check. If someone could have accidentally wired it incorrectly when they were trying to fix it, perhaps they accidentally bypassed the float switch and have it "running hot" all the time.
There is a Cherry-style microswitch inside of the housing that is magnetically operated by the vertical float and float-rod. After years of cycling on and off, the microswitch contacts eventually wear and weld closed which cause the pump to run constantly. This has happened to me twice. The switch is a Cherry D48X 21(8)-2HP-250VAC 1HP-125VAC. The switch assembly is made to only be replaced as a full assembly, but the switch can be carefully removed from the assembly and replaced.
Just buy a new one, they only last soo long.