A09 is only available when DC Failover Box (ASPCB.24/48) is installed. The controller will not operate compressor or heater when the DC Failover Box is active (Free Cooling/Emergency Ventilation only).
This alarm may be present during initial system startup, even if the DC Failover is not installed. In this case, the alarm should disappear upon resetting the controller breaker.
|Possible Cause||Component to Check||Recommended Action|
|DC Failover Box Active||Prime power (208/230V) into the DC failover box.|
Prime power phase: Must have L1, L2 connected in right order on both input breakers (QF1, QF2).
|Verify prime power into the DC failover box.|
Phasing: Should have 0V across left side of QF1 and left side of QF2, 240V across left side of QF1 and right side of QF2.
|Loose/incorrect wiring||Alarm circuit||If A09 is present when the DC Failover Box is not installed or not active, check wiring according to the DC Failover Alarm Circuit diagram.|