Abstract: An immersion well construction including a rigid, heat conductive elongate member having (a) a threaded outside surface portion for threading into a preexisting fluid vessel wall threaded opening, (b) a wrench flat portion disposed proximally of the threaded outside surface portion and (c) a longitudinally extending cavity. The cavity has a main cavity body portion and an adjacent and smaller diameter distal cavity pocket. An inwardly disposed groove is formed on and extends longitudinally along the cavity, such that one or more wires of an electrical sensor held in the cavity pocket can pass in and along the groove and out the elongate member and to an electrical system, such as a remote computer control system.

Abstract: An immersion well assembly for a fluid vessel, such as a boiler, hot water heater or piping system, having an existing threaded opening. A preexisting well housing a mechanical temperature sensor, which is connected to a temperature display or control first system, is removed from the opening, and the present assembly threaded therein. In this assembly are a (replacement) mechanical sensor to be connected to the first system and an electronic sensor. The electronic sensor is positioned in a small distal pocket and the sensor wires travel along a groove adjacent the mechanical sensor and out to a second system, such as a remote computer control system.