Operating status
Table 43: Operating status
Ctrl. State/
Code
Operating status
Description
Push the info button for 3 seconds to see status. If there is a status code, it will be shown on the display. The individual status codes have the
following meanings:
S0
Normal ctrl.
The controller is running normal control. There is no other control taking priority
S1
Hold after defrost
The controller is waiting for other controllers to terminate coordinated defrost
S2
Min ON timer
The compressor is restricted from stopping until the minimum ON timer expires
S3
Min OFF timer
The compressor is restricted from starting until the minimum OFF timer expires
S4
Drip off
The defrost has terminated and the controller is waiting for drip delay to expire, while the water is dripping off the
evaporator
S10
Main switch OFF
The controller has been stopped because the parameter r12 Main switch has been set in OFF or Service position or
the controller has been stopped via Main switch function on DI input
S11
Thermostat cut-out
The air temperature has reached the thermostat cut-out value
S12
Frost protection S4
The air off temperature is below the minimum S4 frost limit (r98, S4 frost protection)
S14
Defrost
The controller is running a defrost cycle
S15
Fan delay
The evaporator fans are waiting to start after a defrost cycle (d07, Fan start delay and d08, Fan start temperature)
S16
Forced closing
The injection valve has been forced closed via a signal on a digital input or from the system manager (compressor
pack is restricted from starting)
S17
Door open
DI signal indicates that the cold room door is open
S18
Melt period
The controller has stopped refrigeration for a short while to turn ice crystals into water and thereby improve air
flow through the evaporator
S19
Modulating temp. control
The air temperature is controlled close to the set point via a modulating temperature control
S20
Emergency control
(1)
The air temperature is controlled according to an emergency procedure due to sensor error (Pe, S2, S3 or S4)
S23
Adaptive superheat control
The superheat of the evaporator is optimized
S24
Start injection
The liquid injection into the evaporator has started
S25
Manual control
Main switch has been set in Service position for manual control of outputs
S26
No refrigerant selected
The refrigerant type has not been selected (parameter o30 Refrigerant)
S29
Case cleaning
A case cleaning operation has been initiated via parameter o46 Case cleaning mode or via a signal on a digital
input or via the AK-CC55 Connect app
S30
Forced cooling
The thermostat has been overruled to run forced cooling via a signal on a digital input
S32
Power-up delay
The controller has just been powered up and the output control is waiting for the power-up delay to expire (pa-
rameter o01, Delay of outputs at power-up)
S33
Air heating
The air heater is energized in order to raise the air temperature (parameters r62, Air heater neutral zone and r63, Air
heater start delay)
S45
Shut down controller
The control has been stopped due to a digital input signal or from the system manager
S48
Adaptive liquid control
The superheat control is running adaptive liquid control with reduced superheat for transcritical CO2 systems with
ejectors. Signal is provided via digital input or from the system manager
(1)
Emergency control:
• If Pe or S2 sensor fails, the controller will operate with a safe opening degree based on normally registered opening degree during day and
night operation.
• If S3 or S4 sensor fails, the thermostat will operate with a registered ON/OFF duty cycle during day and night operation.
(1)
Emergency control:
• If Pe or S2 sensor fails, the controller will operate with a safe opening degree based on normally registered opening degree during day and
night operation.
• If S3 or S4 sensor fails, the thermostat will operate with a registered ON/OFF duty cycle during day and night operation.
AK-CC55 Compact
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