I. Product Overview
The KSD307 series thermostat is a fully enclosed bimetallic strip temperature controller designed specifically for high-power devices such as electric water heaters. Utilizing the principle of thermal expansion and contraction of a bimetallic strip, when the preset temperature is reached, the disc-shaped element momentarily jumps, causing the contacts to actuate rapidly through a mechanism, thus connecting or disconnecting the circuit and providing safety protection for the appliance.
This series offers both automatic and manual reset options to meet the safety protection needs of different application scenarios. It is especially suitable for overheat protection and anti-dry burning protection of products such as electric water heaters, electric heating equipment, and boilers.
II. Product Features and Advantages
- Single-pole single-throw (SPST) contact structure: It adopts a single-pole single-throw (SPST) contact design, which is compact and suitable for circuits that require single-channel on/off control.
- Multiple reset methods are available:
- Automatic reset type: It automatically resumes conduction after the temperature drops to a safe value, and is suitable for systems that allow automatic recovery.
- Manual reset type: After disconnection due to excessive temperature, the reset button must be pressed manually to restore conduction, effectively preventing the equipment from automatically restarting without supervision.
- Rapid disconnection technology: A temperature-sensitive bimetallic strip is used to achieve rapid contact action (sudden snap action) to ensure that the circuit can be quickly cut off when the temperature exceeds the limit.
- High reliability and long lifespan: The speed and force of contact separation are optimized to effectively reduce arc erosion and ensure the controller has a reliable lifespan under load conditions.
- Fully enclosed insulated housing: Made of bakelite (phenolic resin), providing excellent electrical insulation and protection.
III. Application
- Instant electric water heaters and storage electric water heaters
- Electric heating equipment, electric welding machine
- Steam heaters, boilers
- High-power mechanical equipment and electrical products
IV. Main Technical Parameters
| Parameter Items | Automatic reset type | Manual reset type |
| Model | KSD307 (Automatic Reset) | KSD307 (Manual Reset) |
| Contact structure | Single-Pole Single-Throw (SPST) | Single-Pole Single-Throw (SPST) |
| Reset method | Automatic Reset | Manual reset |
| Rated electrical parameters | AC 250V / 35A, 45A, 63A | AC250V / 35A、45A、63A |
| Operating temperature range | 50℃ ~ 150℃ (customizable) | 50℃ ~ 150℃ (customizable) |
| Operating temperature tolerance | ±3℃ ~ ±5℃ | ±3℃ ~ ±5℃ |
| Electrical life | ≥3,000 times | ≥6,000 times |
| Shell material | Bakelite (phenolic resin) | Bakelite (phenolic resin) |
| Wiring method | M4 screw fixing method | M4 screw fixing method |
V. Installation Method
Installation method: Use contact temperature sensing installation, ensuring the metal cover is in close contact with the mounting surface of the controlled appliance. To ensure effective temperature sensing, it is recommended to apply thermal grease to the sensing surface.
Precautions:
- Do not deform or collapse the cover during installation, as this may affect performance.
- To prevent electrical leakage, avoid liquid from seeping into the thermostat and ensure that the casing is free of cracks.
