Testing a high limit sensor

[harryc123]

I believe that my high limit sensor is not working properly. Although my hot tubs pumps run there is no current getting to the best coil which is leading me to believe that this particular
Sensor may be at fault.
The sensor does not have a reset button but instead looks exactly like a 2 inch long silver bullet. I have removed it and tested it for continuity and get no tone. Would this indicate that the sensor is stuck open preventing the circuit board to call for heat?

[Dr. Spa™ Ret.]

There are different sensors for different spas, and you omitted any information on what you might have. But generally, the sensors are "thermistors", which change resistance depending on the temperature. The most common is a 10k ohm thermistor...which will have a resistance of 10,000 ohms at 77 degrees Fahrenheit. As the temperature increases, the resistance decreases. At 104 degrees, the resistance is 5,326 ohms. At 60 degrees, the resistance is 15,314 ohms

There are also 3k ohm sensors...which will have a resistance of 3,000 ohms at 77 degrees Fahrenheit.

[clover]

the hi-limit is not the source of your problem, it has a different purpose and result.

[harryc123]

My tub is a thermospa and the spa pack is made by balboa. I'm unsure of the model number.
basically  there is no voltage getting to the heater despite the tub running. I have tested the heat coil and it appears to be fine. I've checked for voltage and get zero at the coil.
I'm not sure where to go from here.

[Jacuzzi Jim]

 Bad pressure switch.   Any error's on the topside?