I have and Image 631 Spa brought back in the summer of 2002 it has 2 pumps a single speed and a 2 speed pump

Its a 240 volt system wired into a 50 amp GFI spa Box
Its got the Balboa 2000 le conrol pack.
It's always preformed flawlesly.
During the Thanksgiving weekend I drained and refilled it .
Powered backup, everything seemed normal it started right up went into its low speed heating mode, did the heating thing, next morning checked it out it was at 102 everything seemed great. Following night I went for a little dip and noticed it was at 97 degrees... the 2 speed pump was humming and no water flow , I hit the low speed button and it started its heating cycle. Next Morning its was at 97 degrees again motor humming and no water flow. Hit the button a few times to get it going, It went into High when I turned off high, it automatically went into low and started to cycle for water heating. It will not come on by itself when the water drops below 102 degree "temp I always like" . I have to manually start the pump for low to circulate the water for heating. Pumps works fine every time I push the buttons myself, Seems like there is plenty of water flow at the jets

Check every single pvc plumbing union you can find. Be sure everything is tight and nothing is leaking (air or water).

What's happening is that air is creeping into your line from somewhere causing a mild airlock preventing the water from flowing.

Pageup,
Thanks for the reply, I did as you suggested but could not find any leaks of air or water; however since my original post my spa has taken a turn for the worse. My 2 cycle pump will not turn on in low speed. Although I do have high speed and that seems to work just fine. My spa is not heating because of the low speed motor not running. Could this be caused by a bad pressure switch?

I had a tech come out and look at whats troubling my spa, turns out the 2 speed pump has to be replaced. The tech said it's the low speed thats burnt out, The quote was 600+ dollars to replace the pump. Geesh! that hurts.
Is it possible to have the motor rebuilt?

That tech must be driving a Bentley.

You don't need a new motor. Upload a photo of this pump or send one to the email that you see with my pic at the top of this screen.