The introduction of A2L refrigerants marks a significant shift for the HVAC industry. Classified as mildly flammable, A2L refrigerants have a lower GWP than traditional options like R-410A. While they support environmental goals and efficiency, their unique properties require enhanced safety measures, such as improved leak-detection and ventilation protocols.

Many new HVAC systems must now incorporate built-in leak-detection. In the event of a leak, the system is programmed to immediately shut down heating and cooling functions while activating the fan to enhance ventilation. For zoned systems, it is crucial that all dampers remain open to facilitate effective air circulation and prevent refrigerant build-up, which could pose safety risks. New HVAC units are also equipped with auxiliary contacts to control external devices, such as zone damper systems, ensuring they respond appropriately to any leak-detection alerts.

Zonefirst has new A2L products engineered to ensure full compliance with new standards while maintaining system performance:

• Twenty-four-volt spring-return damper systems: For systems using 24V power-closed, spring-open dampers with H32, MMZ3, or MZS4 panels, power is routed through the HVAC unit’s leak-detection contact. If a leak is detected, the circuit breaks, causing dampers to spring open and the fan to activate.

• Plug-in and three-wire power open-closed damper systems: For plug-in and 24V three-wire dampers, an A2LR relay disconnects the R wire from each zone thermostat to the panel, stopping all zone calls and opening all dampers. If a leak is detected, the unit’s auxiliary leak detection circuit triggers this relay, deactivating heating/cooling and activating the fan. To bypass any timing delays and ensure dampers open immediately, the panel must be placed in test mode via a dip switch or jumper. The A2LR is compatible with all Zonefirst panels and can be easily installed in minutes.

“As the HVAC industry continues to evolve towards more sustainable solutions, it’s crucial that we provide products that not only meet regulatory requirements but also enhance system performance and safety," said James Foster, marketing manager at Zonefirst.