[Pump won't start on low (hums), does start on high]

On 6/30/2020 at 5:05 PM, RDspaguy said:

There is one more label, you can barely see the edge of it on the right of the first pic.

The centrifugal switch switches the motor from the start coil to the run coil and could cause it to not start in low but still start in high, due to the higher power created in high. Just as bad bearings can. These are internal motor parts, so if you are not experienced should be checked at a motor shop.

Thank you @rdspaguy !

Great call on the extra label on the back of the pump. Hard to get to, but pictured below. Emerson model T55CXCAS-1179.Also a great call on the centrifugal switch. Definitely no grinding or resistance to spinning, but I found the plate for the switch seems to stick in whatever position I leave it (not springing back to one or the other). Some WD-40 loosened it up some, but not enough to fix the problem. I suspect the next step is to replace that part, and I haven't found anywhere online to even look up, much less buy the part. Any tips where I can do so?

Video of the switch: https://photos.app.goo.gl/V3xm9VA31TbFtdut7

 

[Pump won't start on low (hums), does start on high]

I can't find identifying markings for the motor manufacturer, I'll attach a photo of the labels if you see something I don't. 

The motor is not loud, and I don't recall any resistance or grinding when turning by hand. But I will double check this tomorrow to be sure, because it sure would make sense that some minimal resistance might prevent startup on low-power, but full power wouldn't care.  

The centrifugal switch sounds worthy of looking into. Is that something that would cause the same problem regardless of speed?

[Pump won't start on low (hums), does start on high]

I am so excited to be a new owner of a really old hot tub, and part of a forum of kind helpful folks!

My main pump is two speed. It starts on high just fine, and then if I turn off the jet it will step down to low (filter only) just fine. It won't start on low though, hums for a few seconds 'till the thermal overload trips, repeats after a couple minutes when the thermal overload automatically resets. I can start it on low by spinning it slightly with a screwdriver. This problem began a few days after getting the tub installed and running at my home.

Sounds like a bad start capacitor, right? It was even leaking a little oil. Replaced it. No change. Well, maybe the bigger capacitor is the start capacitor (I really don't think so), replaced it too. No change. 

Is it possible the start capacitor in the pump is the wrong specs to begin with? Maybe the new one I bought was bad on arrival? Any other ideas?

2001 Leisure Bay Genius Series G2
Aqua-flo Flo-master XP2 pump, Model 06626462-2
88-106 MFD 330 VAC start capacitor