Danfoss AK2-SC 255, Reference Manual, Page: 170 / 206

RS.8D.M1.22 AK2-SC 255 Reference Manual 169
also exists whenever the evaporator is refrigerating
and the fixture temperature is more than 5.5 °F
above target range maximum.
In Cut-in status, the valve will be regulated to
search for and maintain the minimum stable super-
heat which for the current load conditions will
become the target superheat.
The Smart Case Controller continually adapts its
superheat target to changes in load on the evaporator
so that refrigerant flow is adjusted accordingly.
When target fixture temperature is achieved, the
evaporator status will change to Normal operation
or Area control.
Area Control: (AKV valves) (Occurs only when modulating control
has been selected during configuration.) The Smart
Case Controller is supplying sufficient refrigerant to
maintain the target fixture temperature. When Area
Control status begins, the Smart Case Controller
learns the dynamics of the evaporator and optimizes
internal parameters for the modulated control
function.
After fixture temperature reaches its target (if that
target is between 23 °F and 50 °F), and after a user-
definable period (default is 60 minutes), the status
will change to Coil conditioning.
Coil conditioning:
(AKV valves.Occurs only when modulating control
has been selected during configuration, and only
when target fixture temperature is between 23°F and
50°F.) Once each hour, the valve is closed for 3
minutes to eliminate uneven frost build-up on the
evaporator. After 3 minutes, control reverts to normal
modulating control.
Low superheat
(AKV valves) The Smart Case Controller has
detected a negative superheat for more than two
minutes, and is reducing refrigerant flow to correct
the situation. The electronic expansion valve will
close for ten minutes, then enter Start-up status.
This cycle will be repeated until a positive superheat
is established. After thirty minutes in Low super-
heat status, an alarm will be generated.
Defrost: A scheduled or manually initiated defrost is in