Inter control capillary thermostats 16a 230v inter control 121051718d01 this capillary thermostat has a closed sensing system that is filled with liquid with the components of the system being sensor bulb capillary tube and diaphragm a change in monitored temperature will cause a change in the volume of the liquid in the system actuating the switch inter control 121051718d01 260c 16a 230vac capillary thermostat