Hussmann KRACK MK Series, Инструкция по установке и эксплуатации

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MK/MV – Medium Profile Series Unit Coolers (E206993_M) 34
9.2.2 DEFROST SETTINGS
The “Defrost Mode” parameter enables defrost initiation either based on demand, or by schedule,
or by monitoring the compressor run time (duration of refrigeration “ON” cycles). Demand or schedule
mode is preferred.
Scheduling defrosts evenly across the day, can be achieved by setting following parameters:
a.
Defrost Per Day
b. Max Defrost Time
c. First Defrost Delay
Based on the hardware, “Defrost type” parameter shall be selected as one of the following options:
a.
Electric
b. Air – off time
c. Hot gas with compressor on
d. Hot gas with compressor off
In electric defrost, the heaters can be either pulsed or permanently on by setting the “Electric Defrost
Mode” parameter appropriately.
The “defrost Fan State” parameter defines the fan operation during defrost (ON/OFF).
Usually fans would be running during air defrost but turned off during other defrost types.
Defrost is terminated when coil temperature reaches the defrost termination temperature defined
through “Defrost Term Temp” parameter.
9.2.3 DRAIN SETTINGS
The “Drain Time” parameter defines the time allotted for water to drip into the drain pans, following
defrost termination (prior to initiation of the refrigeration cycle).
9.2.4 FAN DELAY SETTINGS
After initiation of the refrigeration cycle, the controller will restart the fans once the coil temperature
reaches the “Fan Delay Temp” setpoint. This allows any remaining moisture on the coil surface to freeze
in place, rather than be propelled into the airstream. If this setpoint is not reached, then the fans will
restart only after reaching the “Max Fan Delay Time”.
9.2.5 AIR DEFROST
Units operate fans continuously during defrost, with the liquid line
valve closed. For air defrost to work, the space temperature must be above
freezing. For medium temperature off time defrost applications operating
in ‘Demand’ mode, the KE2 controller performs temperature
initiated/terminated defrost. When using master slave configuration,
temperature sensors for each coil can be connected to the auxiliary inputs
(Aux1, Aux2 and Aux3). See sensor splicing guide in the adjacent diagram.
Note: For best control signal quality use shielded cable for the 0-10V control
signal. Never exceed a maximum of 120ft.
Dimensions shown in inches.