Does this coil come with refrigerant detection, or do I have to buy that separately?

Yes, the AQ-CAPFA2422C3 coil already includes a built-in refrigerant (R-32) leak detection sensor, so you do not need to purchase a separate detection device, because R-32 evaporator coils are designed with an internal sensor that can detect a leak and respond by shutting down cooling/heating while keeping the blower running.

If you have any further questions, please call us and we will be happy to assist you.