When a spa enters watchdog mode it will not leave without a full reboot.
This error can be caused most commonly by any of the following things. (and rarely multiple!)
- Bad boot up sequence or power fluctuation, this can be caused by a small "brown" out, or just unclean solid power.
Solution: Try turning off the spa for 1-2 minutes, then reboot. This allows ample time for the board to get a full reboot. If problem persists move to next.
- Temperature overheat, a dirty filter or low flow conditions, this cause would likely take almost a minute to cause the watchdog error, and should show you other errors before kicking to watchdog, like FLO or OH. If you see no other errors, or the watchdog error shows quickly, move to other reasons.
Solution: If you are experiencing this type of behaviour it may be time to deep clean your filter, or may be time for replacement. Remember 2 years is an average filter life.
- Bad temperature sensor, this is a relatively cheap part that can fail over the years. One easy way to sometimes confirm this part has failed is as follows: Have one person stand at the power for the spa, another person will stand at the spa control panel. When power is applied the person standing at the spa is looking for a reading of the temperature before the display goes to all dashes. (this can be very quick, this is why it usually needs two people) What the person is looking for is the temperature to display a very high temperature, usually over 110 degrees before it kicks to watchdog, if you see this behavior you most likely need a new temperature sensor.
Solution: Replace temperature sensor, we have an instruction sheet printed up explaining how to do this since it is an easy process, we have many clients that perform it themselves. Good eyesight is useful as two of the connections are very small. Don't be rushed, Don't do it in the dark.
- Bad capacitors on main circuit board, many capacitors supplied in electronics in the early 2000's suffered from capacitor plague, this is often fairly easy to diagnose since you can visually inspect the capacitors and see if they have and "bulge" to them, they are usually located near the center of the board and kinda look like batteries soldered onto the board. Then ends should be perfectly flat and if they have a swollen appearance they are bad and can cause the watchdog error. It seems like cold weather or being shut off for a while (circuit board cools) are when capacitors really start causing the watchdog error.
Solution: Replace board, we always recommend replacing the entire board since it is very easy to ruin a board by trying to desolder and replace the capacitors, it can be done, but it is much more reliable to just replace the part. For most users this often would require a service call, although if you are ok reading a wiring diagram or take some good pictures, it is a fairly easy job.