The **135R-R10** is a specific model of an **Electronic Line Voltage Thermostat**, primarily manufactured by companies like **Columbus Electric** or **TPI Corporation**. It is designed for controlling electric heating systems, such as baseboard heaters, radiant ceilings, and space heaters. Below is a breakdown of its technical specifications, internal components, and functional features. --- ### ## Technical Specifications | Feature | Description | | :--- | :--- | | **Type** | Single Pole Single Throw (SPST) | | **Voltage** | 120 / 208 / 240 / 277 VAC | | **Current Rating** | 22 Amps (Resistive) | | **Power Rating** | Up to 5280W @ 240V | | **Temperature Range** | 50°F to 90°F (10°C to 32°C) | | **Action** | Open on Rise (Turns off when heat is reached) | --- ### ### Key Electronic & Mechanical Components #### 1. Bimetallic Sensor The core "brain" of the 135R-R10 is a **bimetallic strip**. This component consists of two different metals bonded together that expand at different rates when heated. As the room temperature rises, the strip bends until it mechanically trips the circuit breaker (switch) to turn the heater off. #### 2. Snap-Action Switch To prevent "arcing" (electrical sparking) between contacts, the device uses a snap-action mechanism. This ensures that the electrical connection is broken or made instantly, which extends the life of the internal copper contacts. #### 3. Anticipator (Heat Feedback) The "R" in the model often signifies a built-in **heat anticipator**. This is a small resistor-like element that generates a tiny amount of internal heat. It "tricks" the thermostat into turning off slightly before the room reaches the target temperature, preventing "overshooting" and keeping the temperature stable. #### 4. Heavy-Duty Terminals Since this is a **Line Voltage** thermostat (handling 120V-277V), it uses thick copper or brass screw terminals. Unlike low-voltage thermostats (24V) that use thin wires, the 135R-R10 is designed to handle high amperage directly. --- ### ### Installation Wiring Overview The 135R-R10 is a **2-wire** (Single Pole) device. * **Line:** The hot wire coming from the power source (breaker box). * **Load:** The wire going directly to the heating element. * **Note:** Because it is Single Pole, it does not have a true "OFF" position that breaks both lines of a 240V circuit; it only breaks one side of the power. --- ### ### Comparison: 135R-R10 vs. Double Pole (DPST) | Feature | 135R-R10 (SPST) | Double Pole (DP) | | :--- | :--- | :--- | | **Wires** | 2 Wires | 4 Wires | | **Safety** | Breaks one line | Breaks both lines | | **Off Setting** | Has a "Low" setting | Has a "No-Current" OFF |