vro 3 wire to 4 wire

[ba1525]

replaced vro pump old pump had 3 wire new pump 4 wire a purple wire three dealers local could not tell me what the forth wire does purple.

 

[ob]

Re: vro 3 wire to 4 wire

The purple wire is "keyed" 12 volt source.

 

[seahorse5]

Re: vro 3 wire to 4 wire

The 3 wire pump used the gray wire as a power lead to run the "computer" chips on the VRO and to tell it the motor's rpm. For better voltage reguation and dependability, the purple 4th wire is a constant DC current ranging from 12-14.5 volts to power the computer. The gray wire now is ONLY used for sensing rpm.