Do you have any other temperature measuring device? Try to take the tank temperature. If temperature is cold, then the thermocouple or termostat is down. If water is hot, it must be no gas, or gas leaked out from chiller gas line. Your case mostly not the compressor spoil.
Babareef is right, try to stop the chiller is it didnt cool down the water. No point wasting electricity and worse if the gas leaks into the pipe which your saltwater flows in. That means dissolving the gas in your tank.
Some cases people dead sleeping in the car due to aircon gas leakage. This gas will make humans dizzy and later go up small lorry.