Good points

Sensor line of 6 meters
Switching point -10 to +15°C
Switchable up to 16 A - 230 V AC
IP65 protection class

Belimo Frost Protection SPDT - AR - 6 metres - 01ATS-1050B

The Belimo 01ATS-1050B is a frost protection device designed for ventilation and air conditioning systems. It monitors the temperature of water and air heaters and protects cooling coils and heating batteries from frost damage. When the temperature in the duct drops below the set threshold, the single-pole double-throw switch (SPDT) automatically activates, triggering a safety action such as closing the air damper or activating an alarm. The Belimo frost sensor features an automatic reset function: once the temperature recovers sufficiently, the device resets without manual intervention.

Benefits and Features

6-metre sensor cable: The long sensor cable covers a large section of the air duct, detecting local cold bridges or point cooling and effectively preventing frost damage.
Automatic reset: Upon temperature recovery, the system resumes operation automatically without requiring further maintenance or manual intervention.
Adjustable switching point (-10 to +15°C): The desired threshold is easily adjustable on-site, factory set at 5°C.
IP65 housing: Fully dust-tight and splash-proof, suitable for use in humid technical spaces.
High switching capacity: The switch supports loads up to 16 A at 230 V AC, ensuring reliable operation.

Effective Frost Protection

The sensor's time constant is less than 25 seconds at an airspeed of 1 m/s in the duct. This means the frost protection device responds quickly to sudden temperature drops and activates protective measures in time, before condensation or ice formation can occur on the heating battery. The 1.5 K switching differential prevents unstable behaviour, ensuring the system does not cycle continuously around the setpoint.

Installation, Maintenance and Applications

The Belimo frost sensor is supplied with a mounting kit including six brackets for easy installation within the duct. The sensor cable is routed in a zigzag pattern across the duct cross-section to effectively monitor the entire airflow. Connections are made via spring terminals up to 2.5 mm², with an M20x1.5 cable gland for cables with diameters between 6 and 12 mm. This frost protection device is used in heating and ventilation units, air handling units, and outdoor air inlets in both residential and commercial buildings.