Question 168Refrigeration & AC - Assistant Engineer

70% to pass

You are checking the supply chilled water temperature thermistor probe on a high- pressure hermetic centrifugal chiller. Using the illustrated chart, what statement is true if the supply water temperature is verified 45°F with a digital thermometer? Illustration GS-RA-48

AWhen checked with control power off and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts.

BWhen checked with control power on and the thermistor probe isolated, the thermistor probe voltage drop should be 3.805 volts.

CWhen checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 11.416 volts.

DWhen checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 3.805 volts.

AI Explanation

The correct answer is D) When checked with control power on and the thermistor probe connected into the circuit, the thermistor probe voltage drop should be 3.805 volts. This is correct because the illustrated chart (GS-RA-48) indicates that at a supply water temperature of 45°F, the thermistor probe voltage drop should be 3.805 volts when the control power is on and the probe is connected into the circuit. The other options are incorrect because option A assumes the control power is off, and options B and C do not match the voltage drop value indicated on the chart for a 45°F supply water temperature.