2 speed pump not working in low speed unless given a boost by switching to high then to low

[Superflo]

I have a Pentair SuperFlo High-Performance Pump 340038 was making noise so I installed a 356630S 2-speed pump (for cost saving during the summer) that was wired IAW the diagram. Line 1 to 1 on the pump, line 2 (Black ) to black switch pig-tail with a wire nut, then yellow from the switch to 2 on the pump, and white from the switch to 3or4 on the pump. Now, when I turn on the pump on low, the pump will energize but will not turn the pump unless the pump switch is moved from low to high fast. Once the switch is cycled then the pump will flow in low. No issues with the high speed. Only at low speed. I did try to isolate the issue by switching the white (high) and yellow (low) wires on the pump to see if the switch was the issue but the low speed did the same. Would it be the capacitor?

 

[sktn77a]

Is it a new pump? Still under the DIY warranty?

 

[setsailsoon]

I have a Pentair SuperFlo High-Performance Pump 340038 was making noise so I installed a 356630S 2-speed pump (for cost saving during the summer) that was wired IAW the diagram. Line 1 to 1 on the pump, line 2 (Black ) to black switch pig-tail with a wire nut, then yellow from the switch to 2 on the pump, and white from the switch to 3or4 on the pump. Now, when I turn on the pump on low, the pump will energize but will not turn the pump unless the pump switch is moved from low to high fast. Once the switch is cycled then the pump will flow in low. No issues with the high speed. Only at low speed. I did try to isolate the issue by switching the white (high) and yellow (low) wires on the pump to see if the switch was the issue but the low speed did the same. Would it be the capacitor?

Super,

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Sounds like it could be a capacitor. Let's see what our experts advise @Jimrahbe @ajw22. May help if you can add a photo of the wiring also.

Chris