Newbie with a question.. I have a 120V 2003 Tiger River Manora spa that's been working fine until about a month ago, when it started shutting off (light, circ pump and main pump) on its own. There is power going to the PC board, so the GFI isn't tripping, and the shutting off happens even if I disconnect the heater element.

It WILL, however, consistantly allow me to start it up again by lowering the thermostat until the relay clicks on and then turning it back up. It runs for about 30 seconds before stopping again.

Is there any way to tell under what conditions the power is shut down (I.e. it thinks there's no water flow, or high heat, or low heater resistance, or..?), as it seems like a sensor's getting confused somewhere.

I'm out of ideas and I'm not sure how much longer these warm days in the northeast are going to continue. Thanks very much for any thoughts!! (The circ pump and filter are less than a year old, too, and it doesn't have an ozonator as far as I can tell. The 20A GFI switch was replaced, as was the PC cable from the thermostat board to the main control board - no difference)

I'd be willing to bet it's a 1993, not a 2003.

It's shutting itself off because it's not detecting flow through the circ. pump line (little pump that runs in obscurity 24hr.'s a day)
When lack of flow is detected, it shuts everything down. You reset it by turning the T-stat down and up again.

Check for the circ. pump for proper operation. It's either a circ. pump failure, flow-switch (and harness) failure, check valve failure, or main circuit board failure.

1st thing, check the tiny pump for circ. pump flow.

Yes - 1993.. I lost my mind there for a second. Good call and thanks for the quick reply!

The circulation pump is fairly new, and when the thermostat is turned down and back, the faint whirr can be heard and the check valve is forced toward the pump, vibrating in the water flow to indicate it's all working as God and Watkins planned. The output can also be felt in the spa itself. Circulation is good.

The only thing I don't see is a way for the board to know what's flowing. There's no electronics/wires/sensors/harness/etc near the circ pump and check valve. Maybe I can get a picture. Do you know where it's supposed to be?

On the front of the control box, on the left side, you'll see a phone cord type plug, and next to that a 2-pin connector harness. That's the harness for the flow-switch.

Unplug it, check for ohms through the flow switch harness. If OHMS are good, then either the harness isn't making good contact with the male prongs of the PCB, or it's a PCB problem. If it isn't Ohming out, replace the flow-switch.

I traced the wire to the previously missed flow switch. Ohms measurement indicated an open circuit, with the spa on or off!

Just to be sure, I wrapped the switch closed temporarily (I am positive water flow is OK), and the spa stayed running for the first time in many weeks.

I will get a replacement flow switch assembly, but at least I don't have to buy the motherboard ($$$).

You're my new hero, and I'd send you a cash reward if I could figure out where to send it.

Thanks again! You and this forum are a sanity-saver.