Halstead - Dual Thermostat Oil boiler control. Robust plastic housing consisting of control and limiter capillary thermostats. Available in either 2 x thermostat (twinstat) configuration or as a single BBSC capillary combination thermostat for greater accuracy and reduced temperature deviation Features Suitable for use with or without immersion pocket Pre-wired internally for ease of installation Anti-tamper control stops Terminals for auxiliary control circuits Customised colours and branding Operation Control: a rise in temperature causes the expansion of liquid within the bulb and capillary. The liquid acts on a bellows assembly within the plastic housing to open and close electrical contacts. High limit: in case of abnormal rise in temperature, liquid expansion in the bulb and capillary of the dedicated safety limiter acts on a bellows assembly to open electrical contacts. The limiter is manually resettable. Technical characteristics TYPE - Dual control and regulation TEMPERATURE