Siemens TH-188 Direct/Reverse Acting Thermostat - Unit Mounted

The TH 188 Unit Mounted Thermostat is a remote bulb, gradual acting pneumatic instrument which maintains a pre-selected temperature by positioning pneumatic devices that control a heating or cooling medium. Features: Liquid filled sensing element Direct acting (DA), reverse acting (RA), and heating-cooling models (HC) Mounting bracket provided Application: The TH 188 thermostat is mounted in fan coil units and unit ventilators to control a space temperature in applications where a wall thermostat cannot be used. In unit ventilator applications, where the unit mounted thermostat pilots a Limitem, use a thermostat having a 40 scim (11ml/s) restrictor. The Limitem has a built-in bleed to prevent control air from being trapped. To assure good control, the remote bulb sensing element must be located so that space air passes over it continuously.