Check Redundant Return Air Sensor (RAT2)

Redundant Return Air Sensor RAT2 is out of range, and the unit switches the active probe to RAT.

A Redundant Return Air Temperature Sensor (RAT2) is installed, configured, and is not within the range of -53 to +158°F (-47 to +70° C).

Engine and Electric Operation: If RAT2 is selected as the active probe, switch active probe to RAT probe.

Auto reset when sensor is in range or, alarm may be manually reset using the display mounted keys or by turning the unit off, then back on again.