To make sure it detects your cardio belt properly, we advise you to check the following points:

1. Make sure your cardio belt uses the Bluetooth Smart protocol. Belts using the ANT+ protocol are not compatible with this product.

2. Activate HRM mode in the Settings > HR Sensor > HR Sensor menu: ON

3. Pair your cardio belt up to your watch. By pairing them up, you can connect your belt to your watch. This is only necessary when using a belt for the first time or after resetting your watch. 

4. Moisten the sensors on the elastic strap & position the belt properly below your pecs.

Check out this video to learn more!