I have a Caldera Vanto spa, and the other day i noticed the 2 speed pump wouldnt run on low speed, but ran fine on high speed. The second pump worked fine. As soon as i turned the pump to high speed the heater then came back on and worked as it noticed the flow. I pulled the capacitor and tested it as it was dead. I replaced it and still having the same symptoms. I thought maybe the pump was bad, but when i swapped the low speed and high speed wires, the pump would pump low speed when i turned it on. This showed me that the pump was able to run at low and high speed.
The next thing i tried was to check the power coming from the main board but didnt seem to getting power from the board when i went to low speed. This tells me that for some reason the board isnt triggering that plug to turn on on low speed.
Does anyone have any ideas what would cause this? My gut is telling me the board, but was hoping it would be something i could replace on it.