Coordinated defrost via network
A coordinated defrost among multiple controllers can be obtained via data communication. The controllers will
have to be added to a coordinated defrost group in the AK-SM system manager. When a defrost cycle is scheduled
the system manager will start a defrost in all controllers. After the defrost, the individual controllers will move into
waiting position. When all controllers have terminated the defrost all controllers will continue with the rest of the
defrost cycle (drip delay and fan delay).
Figure 10: Coordinated defrost
Gateway/
System Manager
Danf
oss
84B2453
Defrost on demand
1. Based on compressor runtime:
when the aggregate compressor runtime has passed a set time, a defrost will be
started.
Figure 11: Based on compressor runtime
Danf
oss
80G8459
Defrost start
Σ
t
2. Based on temperature:
the controller will constantly follow the temperature at S5. Between two defrosts, the S5
temperature at compressor cut-out will become lower the more the evaporator ices up (the compressor operates for
a longer time and pulls the S5 temperature further down). When the S5 temperature passes a set allowed difference,
compared to the set thermostat cut-out value the defrost will be started. This function can only work in 1:1 system.
Figure 12: Based on temperature
Danf
oss
80G8458
Defrost start
S5
T
t
Case controller, type EKC 223 and EKC 224
© Danfoss | Climate Solutions | 2023.05
BC432222569027en-000201 | 10