Danfoss Optyma AK-RC 204B, 205C, 305W-SD Refrigeration Controller

Data Sheet

The Danfoss Optyma AK-RC range offers a comprehensive selection of refrigeration controllers designed for flexibility in cold room applications. These controllers are engineered to minimize installation time and energy consumption while ensuring excellent food quality.

Key Features

Easy wiring and high environmental protection simplify installation.
Fast commissioning with a guided start-up wizard.
Multi-level platform with extensive functionalities and logic for diverse applications and food safety compliance.
Advanced defrost logic for improved energy efficiency and performance.
Integrated thermal-magnetic circuit protection.
Large, clear, and intuitive display for quick information access.
Comprehensive store management via integration with the Danfoss ADAP-KOOL system using Modbus.
Standard Modbus connectivity for third-party integration.
Optional cloud and remote connectivity via the ProsaLink application, IoT module, and Cloud service.

Product Range Overview

Technical Characteristics	AK-RC 204B	AK-RC 205C	AK-RC 305W-SD
Danfoss Ref.	080Z5001	080Z5002	080Z5003
Electrical Supply	230 V AC	230 V AC	100 to 240 V AC
Dimensions (WxHxD) in mm	290 x 141 x 84.4	290 x 141 x 84.4	290 x 141 x 84.4
Sealing	IP65	IP65	IP65
Electrical Protection	2 SPDT 20 A	Yes (16 A) 1 SPDT 16 A	1 SPDT 16 A
Digital Outputs	2 SPST 16 A	2 SPDT 20 A	2 SPDT 20 A
Analog Inputs	2 NTC	2 SPST 16 A	2 SPST 16 A
Digital Inputs	1	2 NTC	2 NTC
Wizard Menu	Yes	1	1
Temperature Control	Yes	Yes	Yes
Advanced Defrost Function	Yes	Yes	Yes
Modbus	Yes	Yes	Yes
Data Logger	Option with PR-SC4	Option with PR-SC4	Option with PR-SC4

Functions

The Optyma Control regulator manages the entire cold room system, including:

Compressor
Crankcase Heater
Evaporator Fans
Defrost Heater (up to 2 evaporators)
Solenoid Valve
Cold Room Light
Door Frame and Drainage Heater Elements
Door Control (activity and alarms)
Remote Setpoint and Defrost Modification
Alarms (Temperature, Door Open)

Figure 1: Standalone System depicts a single cold room setup where the Optyma controller manages essential components like the compressor, fan, defrost heater, and solenoid valve.

Figure 2: Distributed System illustrates a multi-room setup where Optyma controllers are networked, typically via Modbus, to manage individual cold rooms within a larger system.

The AK-RC 305W utilizes Adaptive Defrost logic to optimize the operation of drainage and plate heaters. This reduces electrical consumption and fan regulation by leveraging the evaporator's thermal inertia (frost), leading to:

Reduced compressor activations.
Lower energy consumption.
Decreased mechanical stress on components.
Minimized defrost cycles and duration, reducing thermal stress, increasing setpoint time, lowering energy use, and mitigating gas leakage risk.

Applications

The controllers offer easy and quick mounting with simple wiring. The kit includes 2 x 10K NTC sensors. Configuration is streamlined through a wizard:

Wire the controller.
Power up the unit.
Use the Wizard to select the appropriate application based on Table 2: Applications InI.
Configure the desired setpoint.

Table 2: Applications InI

InI(1)	Installation Type	Cooling Control	Pump Down	Defrost	Evap. Fans
0	Demo Mode: Displays temperature on screen but does not regulate temperature or activate relays.
1	Solenoid	No	Electric	Yes
2	Solenoid + compressor	Yes	Electric	Yes
3	Solenoid + compressor	No	Electric	Yes
4	Solenoid	No	Air	Yes
5	Solenoid + compressor	Yes	Air	Yes
6	Solenoid + compressor	No	Air	Yes
7	Solenoid + compressor	Yes	Hot gas	Yes
8	Solenoid + compressor	No	Hot gas	Yes
9 (2)	Solenoid + compressor	Yes	Cycle inversion	Yes
10(2)	Solenoid + compressor	No	Cycle inversion	Yes
11(2)	Solenoid valve	No	Static	No
12(2)	Solenoid + compressor	Yes	Static	No
13(2)	Solenoid + compressor	No	Static	No

(1) See Electrical Diagrams. (2) Not available for 305W-SD.

Electrical Diagram Components

Compressor [Compressor]
Crankcase Heater [Crankcase Heater]
Fan [Fan]
Defrost Heater [Defrost Heater]
Solenoid Valve [Solenoid Valve]
Hot Gas Valve (HG) [Hot Gas Valve]
Condenser Solenoid Valve for Hot Gas (COND) [Condenser Solenoid Valve]
4-Way Reversing Valve [4-Way Reversing Valve]
Auxiliary Relay 1 (AUX. 1) [Auxiliary Relay 1]
Auxiliary Relay 2 (AUX. 2) [Auxiliary Relay 2]
High-Low Pressure Controller [High-Low Pressure Controller]
High Pressure Controller [High Pressure Controller]
Low Pressure Controller [Low Pressure Controller]

Wiring Diagrams

The following figures detail the wiring configurations for different applications (Inl values) and controller models:

Figure 3: Inl = 1, 4, 11 (AK-RC 204B): Shows wiring for RS485, NTC, DIG. IN, and main power terminals (SSV, DEF, FAN, COOL, AUX 1, H. CRANK.) with current ratings.
Figure 4: Inl = 2, 3, 5, 6, 12, 13 (AK-RC 204B): Details wiring for various Inl configurations on the AK-RC 204B.
Figure 5: Inl = 7, 8 (AK-RC 204B): Wiring diagram for specific applications on the AK-RC 204B.
Figure 6: Inl = 9, 10 (AK-RC 204B): Wiring diagram for specific applications on the AK-RC 204B.
Figure 7: Inl = 1, 4, 11 (AK-RC 205C): Wiring for the AK-RC 205C, including AUX 2 terminals.
Figure 8: Inl = 2, 3, 5, 6, 12, 13 (AK-RC 205C): Wiring for various Inl configurations on the AK-RC 205C.
Figure 9: Inl = 7, 8 (AK-RC 205C): Wiring diagram for specific applications on the AK-RC 205C.
Figure 10: Inl = 9, 10 (AK-RC 205C): Wiring diagram for specific applications on the AK-RC 205C.
Figure 11: Inl = 1, 4 (AK-RC 305W): Wiring for the AK-RC 305W, noting its 100-240V power supply.
Figure 12: Inl = 2, 3, 5, 6 (AK-RC 305W): Wiring for various Inl configurations on the AK-RC 305W.
Figure 13: Inl = 7, 8 (AK-RC 305W): Wiring diagram for specific applications on the AK-RC 305W.
Figure 14: Inl = 2, 5, 7, 8 (AK-RC 305W): Wiring diagram showing different inputs for components like drainage heaters, door frame heaters, and hot gas valves on the AK-RC 305W.
Figure 15: Danfoss Cloud Service: Illustrates the connection of the SC4 module to the AK-RC via Modbus RS485 for cloud connectivity.
Figure 16: Diagram of the SC4 module.
Figure 17: AK-RC 204B Power Connection: Shows the power input for the AK-RC 204B.
Figure 18: AK-RC 205C Power Connection: Shows the power input for the AK-RC 205C.
Figure 19: AK-RC 305W Power Connection: Shows the power input for the AK-RC 305W.
Figure 20: Details the 3-wire Modbus connection between the AK-RC controller and a Prosa regulator.
Figure 21: Displays example controller screen readouts and specifies Modbus parameters: 'b20' for Modbus Address (set to 1) and 'b21' for Communication Speed (set to 1, 19200 baudrate).

Product Specifications

Technical Data

Characteristics	Mounting Specifications	AK-RC 204B	AK-RC 205C	AK-RC 305W
Supply		230 V~±10%, 50 Hz ±5%	230 V~±10%, 50 Hz ±5%	100-240 V~50/60 Hz
Max. power consumption during operation		6.3 VA
Max. current intensity		15 A
SSV/DEFROST Relay - SPDT - 20 A	NO	EN60730-1: 15 (15) A 250 V~	EN60730-1: 15 (13) A 250 V~	EN60730-1: 15 (15) A 250 V~
	NF			EN60730-1: 15 (13) A 250 V~
VENT Relay - SPST - 16 A		EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~
REFR Relay - SPST - 16 A		EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~
AUX 1 Relay - SPDT - 20 A	NO	EN60730-1: 15 (15) A 250 V~	EN60730-1: 15 (15) A 250 V~	EN60730-1: 15 (15) A 250 V~
	NF		EN60730-1: 15 (13) A 250 V~	EN60730-1: 15 (13) A 250 V~
AUX 2 Relay - SPDT - 16 A	NO	EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~	EN60730-1: 12 (9) A 250 V~
	NF	EN60730-1: 10 (8) A 250 V~	EN60730-1: 10 (8) A 250 V~	EN60730-1: 10 (8) A 250 V~
Number of relay operations		EN60730-1: 100,000 operations
Probe temperature range		-50.0 to 99.9 °C
Resolution, setting, and differential		0.1 °C
Thermometric accuracy		±1 °C
NTC probe tolerance at 25 °C		±0.4 °C
Working ambient temperature	AK-RC 204B: -10 to 50 °C	AK-RC 205C: -10 to 45 °C	AK-RC 305W: -10 to 50 °C
Storage ambient temperature		-30 to +60 °C
Degree of protection		IP65
Degree of pollution		II acc. to EN 60730-1
Control device classification		Built-in type, automatic operation Type 1 B, for use in clean environments, with logic support (software), Class A, and continuous operation. Degree of contamination 2 acc. to UNE-EN 60730-1. Double insulation between power supply, auxiliary circuit, and relay output.
Pressure test temperature		Accessible parts: 75 °C; Parts positioning active elements: 125 °C
Test current for radio interference suppression		270 mA
EMC tested voltage and current		207 V, 17 mA
Mounting type		Fixed indoor
Internal buzzer		Present

Dimensions

Figure 22: AK-RC 204B Dimensions shows the external dimensions of the AK-RC 204B unit.

Figure 23: AK-RC 205C Dimensions shows the external dimensions of the AK-RC 205C unit.

Figure 24: AK-RC 305W Dimensions shows the external dimensions of the AK-RC 305W unit.

Mounting

Figure 25 illustrates a mounting step.

Figure 26 shows mounting with hardware components.

Figure 27 details the required drill hole sizes (Ø 3 mm / 1/8 in. and Ø 5 mm / 3/16 in.) and screw quantities (x3).

Figure 28 provides a close-up view of a mounting detail.

Figure 29 displays mounting dimensions in both inches and millimeters, indicating spacing for wall mounting.

Ordering Information

Table 4: Product References

Description	Part Number
AK-RC 204B	080Z5001
AK-RC 205C	080Z5002
AK-RC 305W	080Z5003

Table 5: Accessory References

Description	Includes	Qty.	Part Number
10K NTC Sensor 3.5 m	10K NTC Sensor 1 x 1.5 m	1	084N3210
10K NTC Sensor 8.5 m	10K NTC Sensor 1 x 3.0 m	50	084N3208
10K NTC Sensor 1.5 m	High-accuracy NTC Sensor 2 x 1.5 m	150	084N3200
High-accuracy 10K NTC Sensor 1.5 m(1)		1	080Z3216

(1) Only for AK-RC 305W-SD.

Certificates, Declarations, and Approvals

This section lists certificates, declarations, and approvals for the product type. Individual part numbers may incorporate some of these, and local approvals might not be listed. For the latest status, visit danfoss.com or contact a local Danfoss representative.

Table 6: Certificates, Declarations, and Approvals

File Name	Document Type	Subject of Document	Approval Authority
AK-RC 204B	EMC/LVD/RoHS	CE	EU
AK-RC 205C	EMC/LVD/RoHS	CE	EU
AK-RC 305W	EMC/LVD/RoHS	CE	EU

Online Assistance

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