Hill Phoenix Reveal and OnDisplay cases use Danfoss-based AK-CC and ADAP-KOOL controllers in most North American configurations. Here's the field reference for the alarms you'll actually see in a Tampa Bay grocery service call.
Hill Phoenix has shipped two predominant case controller families: the older AK-CC 210/250 on cases through about 2015, and the current AK-CC 550A with the EEV-capable variants on Reveal and OnDisplay lines. Reveal-branded merchandisers from 2018 forward almost universally use AK-CC 550A. The fault codes overlap heavily but a few are unique to the 550A.
A1 / High temperature: S3 or S4 above the high-alarm setpoint for longer than the alarm delay. Investigate door cycles, defrost, airflow before refrigerant. A2 / Low temperature: S3 below low-alarm setpoint; on a multi-deck check that defrost is initiating. A45 / S3 sensor error: discharge air probe failed or disconnected. A46 / S4 sensor error: return air probe.
A11 / Cut-out from thermostat: the controller has called for cooling but the rack isn't responding — check upstream solenoid and the rack controller. A13 / Defrost stop on time: defrost terminated on time, not on temperature. Repeated A13s mean defrost heater or termination probe failure.
A21 / Low superheat: EEV is running too open. Common cause is a bad temperature probe at the EEV outlet; verify probe before adjusting superheat reference. A22 / High superheat: EEV starved. Check liquid line temp upstream of the case — if it's warm, the case is starved at the rack, not at the valve.
Hill Phoenix racks at most Tampa Bay stores tie cases back to a Danfoss AK-SM 800 or 850 system manager via the LonWorks or RS-485 trunk. Loss of network shows as A75 / RTC error or A78 / Network fault at the case. Almost always a wiring termination problem at the trunk junction box, not a controller failure. Check end-of-line termination resistors and trunk continuity first.
Press the wheel on the AK-CC 550A face to enter the menu, navigate to Service > History. You get the last 24 hours of S3 (discharge air) at 1-minute resolution and a rolling event log of alarms and defrost cycles. This is the single most useful diagnostic tool on a Hill Phoenix case — patterns in the temp trace tell you whether you have a defrost issue, a door issue, or a refrigeration issue without leaving the front of the case.
Three access levels on the 550A. Operator level is unrestricted view plus setpoint changes within the operator band. Service level (PIN-protected) opens defrost schedule, alarm thresholds, and EEV setpoints. Hill Phoenix factory level opens the underlying case-model parameters and isn't shipped with field documentation; that's a manufacturer service call.
Document the parameter set first via the AK-ST 500 service tool (every Hill Phoenix-credentialed contractor carries one) or the AK-SM rack controller's case backup function if the case is networked. Without backup you're rebuilding from the case spec sheet — slow, and easy to get wrong on EEV setpoints.
Discharge air probe (S3) sensor error — the controller is reading out-of-range. Check probe wiring at the controller and at the probe; replace the probe if continuity is bad.
Defrost is terminating on the time-limit safety because the termination temperature was never reached. Cause is almost always a failed defrost heater or a defrost termination probe out of position or out of calibration.
Only with service-level PIN access. Operator-level access can change setpoint within the operator band but not defrost schedule, alarm thresholds, or EEV setpoints.
24 hours of S3 discharge air at 1-minute resolution on the controller itself, plus a rolling alarm and defrost event log. Longer history requires the rack-level AK-SM system manager or an external IoT logger.
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