ECKELMANN Case Controller UA 4 E Series, Инструкция по эксплуатации

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Firmware V3.13 21.04.2021 73/466
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5.8.3 Discharge gas defrosting (hot gas defrosting)
Discharge gas defrosting involves feeding discharge gas into the evaporator and can be performed with
either hot or cold gas. The discharge gas is supplied from a point upstream of the condenser (hot gas
defrosting) or from the receiver downstream of the condenser (cold gas defrosting).
Notes on discharge gas defrosting (controller type UA 131 E, UR 141 TE)
These notes apply to two-pipe discharge gas defrosting. The defrost relays are used to control special
solenoid valves specific for discharge gas defrosting. In discharge gas defrosting allowance is made for the
specific properties of the discharge gas:
Demand defrost counter ignored on initiation of defrosting
No internal initiation of defrosting
No interruption of defrosting in occurrence of temperature alarm
Discharge gas defrosting requires the system to include a pack controller. Case/coldroom controllers
involved in discharge gas defrosting must be assigned to a pack controller through the Pack No. parameter.
With VS 3010 BS pack controllers, the Refrigeration Pack parameter must also be set on the case/coldroom
controller.
Activating discharge gas defrosting with UA 131 E:
In order to activate the discharge gas function of the UA 131 E, the parameter HG operation (Discharge Gas
Mode, menu 6-3) must be set ON on the controller.
Activating discharge gas defrosting with UR 141 TE:
Discharge gas defrosting can be performed at any time with the UR 141 TE and does not need any further
parameters to be set.
Termination of discharge gas defrosting with UA 131 E:
Defrosting is terminated by the defrost termination temperature sensors and can be carried out immediately. In
contrast to the UA 131 DD (see UA 300/UA 400), there is no time delay before the start of defrosting.
Termination of discharge gas defrosting with UR 141 TE:
Defrosting is terminated by the defrost termination temperature sensors without delay. If an internal defrost
timer is set on controller types suitable for discharge gas defrosting, it will be changed automatically to external
defrosting by the pack controller the first time discharge gas defrosting is initiated. This prevents the case
controller from automatically initiating defrosting.
ATTENTION
Compressor damage! Danger due to liquid refrigerant on the suction side of the compressor!
Discharge gas defrosting as described herein is D2D two-pipe discharge defrosting, which can be
performed only with hot gas.
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ATTENTION
Compressor damage! Danger due to liquid refrigerant on the suction side of the compressor! At
first start with the UA 131 E, defrosting is initiated directly after starting. If the system is not interlocked
by appropriate pack controller control leads for initiation of discharge gas defrosting, it is then possible
for liquid refrigerant to enter the suction line for example. Therefore, in applications with discharge gas
defrosting, always make sure that manual defrosting is disabled when the controller starts and the
defrost timer is set to external defrosting. Alternatively or additionally, operation of the positioners
specific to discharge gas can be interlocked by the pack controller by means of suitable control leads.
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Discharge gas defrosting cannot be used together with the master-slave function. With discharge gas
defrosting the operation must be terminated when the CAN bus defrost command ends, whereas with
master-slave defrosting the operation always continues until the safe defrost time expires. Alarm will be
generated by the controller if such a combination is set.
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