AO Smith SQS1102R Motor only works on low speed

  • Last Post 27 June 2017
PeterMartinez posted this 22 April 2017

Just a few days ago I notice that my pool pump was no longer working. On inspection I notice that it will start on low speed, but when I try to start it on high speed it hums and turns a bit, then the overload protector kicks in and the motor shuts off. I replace both run capacitor and start capacitor and no changes. The motor is not even 2 years old so its hard to believe that the windings are burnt out. Any ideas where I should look next?

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InyoRob posted this 22 April 2017

Hello Peter - How do you switch the speeds on the motor. Is it a manual switch or is the motor connected to a control panel?

VK3131 posted this 21 June 2017

I have the same problem with a 1 1/2 year old Jandy Stealth 2 speed main pool pump I purchased from INYO Dec 2015.  Ran fine until the other day I tried to start it on high for backwash and it tripped out (buzzed then overload tripped it off for a while).  I have a 2 spd timer wired into main timer.   I suspected the start capacitor because once started on low, I can flip the timer into high and it will run all day no issue.  But try to start from full stop to high it trips offs.  The OP above says he replaced the capacitors so has me thinking either his capacitor is still an  issue or could it be a centrifugal switch issue?

Service posted this 27 June 2017

Hi VK3131,

We reached out to one our motor engineer friends and they stated the following....

This motor is PSC on high speed, and split phase on low speed.   On high speed there is a main winding, and phase winding with a run capacitor.  If any of these components are not functional, the motor will not start.  If low speed is on, it may be possible for some motors to continue running when switched to high.  The run capacitor is 25 MFD, 440 volt.  Previously, a 25 MFD, 370 volt capacitor was used.  The voltage rating on a capacitor is the amount of voltage it can withstand, including line voltage, and voltage impressed on it by the winding.  The voltage was increased from 370 to 440, to allow more tolerance against high capacitor volts.  Running lightly loaded is one cause of high capacitor volts.  There is a good chance this motor is lightly loaded, compared to the design potential, given the fact that this motor will run all day on high speed.  The capacitor is the easiest thing to check.  If it checks ok, the likely cause of the problem is a shorted phase winding.  The 440 volt capacitor is 2” in diameter, and the previous 370 volt capacitor was 1 ¾” in diameter.

Thank You