I have a Teledyne Larrs Flextemp Lite for my spa. It has been working fine but recently the heater will not stay on. It works for about 10 minutes then shuts off. I bypassed the pressure switch and I have the same results. I'm thinking maybe the thermistat?

Hey, Did you ever fix it? If so, what was it, as I am experiencing a similar problem, but my cycles on and off after about 5 to 10 seconds instead of every 10 minutes like yours.
Thanks.