Abstract: A temperature sensing device including a conduit or tubular section acting as a condenser extending throughout the interior of a refrigerated environment such as a refrigerated food case with an evaporator section extending to a collection pot located remote from the condenser tube such as under the shelving of freezer cases, the entire tubular section being hermetically sealed with respect to the ambient and filled with refrigerant in fluid flow communication with the collection pot which serves as a reservior for the refrigerant, the refrigerant in the condenser section acting to assume the average temperature reading in the case environment and communicating the reading to the collection pot which has therein a sensing well located below the level of liquid refrigerant in the pot so that a temperature sensing probe, such as a thermistor device, when placed in the well will remotely and accurately monitor the refrigeration requirements of the food case to maintain a predetermined desired average temperature