Real-Time Clock; Coordinated Defrost - Danfoss AK-CC55 Water Loop User Manual

AK-CC55 Water Loop
Electrical defrost sequence where the defrost heater is ON during defrost, compressor is stopped and fans are
running during defrost but stopped during drip.
Figure 31: Hot gas defrost
HGV
A
Hot gas defrost sequence where compressor and hot gas valve is ON during defrost and fans are OFF.
Fan control during defrost
During the defrost sequence, the evaporator fans can be controlled in one of the following ways:
1. The fan is OFF during the entire defrost sequence
2. The fan is ON during the entire defrost sequence except during fan delay state
3. The fan is ON during defrost state and is OFF during the rest of the defrost sequence
4. Like option 2, however the fans can be stopped if the selected defrost stop sensor exceeds a set fan stop limit

Real-time clock

The controller has a built-in real-time clock which can be used to start defrosts. This clock has a power reserve of
four days.
If the controller is equipped with data communication, the clock will automatically be updated from a Danfoss
system manager.

Coordinated defrost

There are two ways in which coordinated defrost can be arranged.
Figure 32: Coordinated defrost options
System manager
Either with wire connections between the controllers or via data communication:
Wire connections
The digital input DI2 must be configured for coordinated defrost and wiring must be connected between the
relevant controllers. When one controller starts a defrost, all the other controllers will follow suit and likewise start a
defrost. After the defrost, the individual controllers will move into waiting position. When the last controller ends
defrosting, the defrost sequence will continue with drip delay.
© Danfoss | Climate Solutions | 2022.04
X
B C D
Max 10.
X Time
A Defrost
B Hold
C Drip
D Fan delay
HGV Hot Gas Valve
BC378540472015en-000101 | 21