This Three-Phase Capillary Thermostat is a heavy-duty industrial temperature controller designed for high-voltage environments. Unlike standard single-phase thermostats, this device is built to switch all three power lines simultaneously, making it the primary safety and control component for large industrial ovens, water heaters, and fryers.

It is typically available in two common temperature ranges: 30–110°C (ideal for water heating/bain-maries) and 50–300°C (ideal for baking and industrial ovens).

Key Features

• Three-Pole Switching: Specifically designed for 380V-440V systems. It breaks all three lines of a 3-phase heater at once, ensuring the heating element is completely de-energized.

• Mechanical Operation: Works without an external power supply. It uses a liquid-filled bulb and a capillary tube; as the bulb heats up, the liquid expands and mechanically trips the switch.

• Dual Range Options:

  • 30–110°C: Used for precision low-heat tasks like dishwashers, sterilization, and water tanks.

  • 50–300°C: Heavy-duty range for pizza ovens, plastic machinery, and industrial kilns.

• Safety Cut-out: Often used as a "Manual Reset" safety limit. If the primary controller fails, this switch acts as a fail-safe to prevent fires or equipment damage.

Common Applications

• Industrial Ovens: Controlling or limiting the heat in commercial baking or powder coating ovens.

• Large Water Heaters: Used in industrial boilers and commercial kitchen "bain-maries."

• Fryers: Maintaining oil temperature in high-volume deep fryers.

• Plastic Processing: Controlling the temperature of molds or extrusion barrels.

Installation & Safety Notes

1. Bulb Placement: The sensing bulb (the thick metal tip at the end of the wire) must be in direct contact with the medium being measured (air, water, or metal surface) for accurate readings.

2. Avoid Kinking: The capillary tube is a hollow pipe filled with fluid. Do not bend it sharply or kink it, as this will cause the thermostat to fail permanently.

3. High Voltage Warning: Since this handles 440V, ensure the unit is mounted in a grounded metal enclosure and that all terminals are properly insulated.