OH Error code, spa not hot, pump doesn't run

[Dux]

My hot tub display shows OH then 125. Not hing changes when I shut off the breaker and turn it back on. The water, the heater, everything, is room temperature. Would this not be the temperature sensor? My Google search indicated a few things other than that, like low flow or the pump isn't working. It seems to me that, in those cases, the heater would get hot, too hot, and then shut off. This error shows as soon as I turn it on. The pump doesn't go. The heater doesn't go. But it seems to me that, if the temperature sensor thinks the water is 125 deg, it won't let the heater start (and not the pump either?).

Is there some way to test the temperature sensor?

Thanks,

Dux

 

[JamesW]

Test resistance of sensor. It should be about equal to the resistance as shown on a 10k thermistor chart. For example, at 77 Fahrenheit, the resistance should be 10,000 ohms.

If the reading is 125 Fahrenheit on the display, the resistance should read 3,382 ohms.

If the sensor is not reading the correct resistance for the actual temperature, it's bad.

 

[Dux]

Thanks. I checked the resistance. I get 1,145 ohms. The temperature is about 68 degrees Fahrenheit. So, I should be getting something in excess of 10,000 ohms. I'm going to guess the mas temp reading is 125 but the sensor probably thinks it's even hotter than that. So, it would see to imply the sensor has ceased to function. Do you agree?

 

[JamesW]

Yes, probably a bad sensor.