The iO-HPA module is designed to detect air-to-air heat pump system failure by monitoring the “W” voltage signal from the thermostat and the temperature of the hot gas line. If there is a call for heat but the compressor fails to run after 12 minutes, a buzzer will sound.
The module is equipped with an alarm switch to silence the buzzer. The Heat Pump Alert (iO-HPA) notifies the homeowner or building owner if the heat pump has failed. When a heat pump failure occurs in the winter, the owner most likely will not be aware of the issue. In many cases, the first indication that there is a problem is when the owner receives a large electric bill. This happens because they have been heating with backup electric heat instead of the heat pump.
Check out the spec sheet/install guide for more information.