Viessmann SCU224 User Manual
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Viessmann SCU224 User Manual

Viessmann SCU224 User Manual

Temperature controller
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SCU224
Mounting
Connection

Application examples

Operation
Troubleshooting
en-US/CA
Manual
Thank you for buying this product.
Read this manual carefully to get the best perfomance from this unit.
Please keep this manual carefully.
5443203 v1.0 02/2010

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Summary of Contents for Viessmann SCU224

  • Page 1: Application Examples

    SCU224 Mounting Connection Application examples Operation Troubleshooting en-US/CA Manual Thank you for buying this product. Read this manual carefully to get the best perfomance from this unit. Please keep this manual carefully. 5443203 v1.0 02/2010...

  • Page 2: Table Of Contents

    SCU224 Contents General ..............2 System layout 8 ..............24 System-specific functions ..........26 Overview ..............3 System layout 9 ..............28 1. Installation ............4 1.1 Mounting ................4 System layout 10 ............... 30 1.2 Electrical connection ............4 2. Operation and function ........32 1.3 Data communication/ Bus ..........5...

  • Page 3: Overview

    ê • User-friendly operation • Housing with outstanding design • Extra-low power consumption 2.6" Included with the SCU224: 66 mm 1 × SCU224 1 × accessory bag 1 × spare fuse T4A 2 × screws and wall plugs 4 ×...

  • Page 4: Installation

    SCU224 1. Installation WARNING! Electric shock! 1.1 Mounting Opening the housing will expose display live parts! Î Switch off power supply and discon- nect the device from power supply before opening the housing! The unit must only be installed push button •...

  • Page 5: Data Communication/ Bus

    SCU224 Connecting the device to the power supply must always be the last step of the installation! The power supply to the controller must be carried out via an external power switch (last step!). The supply voltage must be 100 ... 240 V~ (50 ... 60 Hz). Flexible cables must be attached to the housing with the enclosed strain relief and the corresponding screws.

  • Page 6: Terminal Allocation In The Different System Layouts

    1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum Note: tank temperature (S MX) is reached. Viessmann Vitosol collectors cannot be used in Sensors S3 and S4 can optionally be connected for mea- drainback systems. surement purposes.
  • Page 7 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 8: System Layout 2

    SCU224 System layout 2 Heat exchange from tank 1 to tank 2 will be operated by The controller calculates the temperature difference bet- relay 2, if the temperature difference between sensors S3 ween collector sensor S1 and tank sensor S2. If the diffe-...
  • Page 9 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 10: System-Specific Functions

    SCU224 System-specific functions The following adjustments are used for the specific function in system layout 2. ∆T control for the heat exchange between 2 tanks Reference sensors for this function are S3 and S4. DT3O: Switch-on temperature diff. In system layout 2 the controller is equipped with an addi- Adjustment range: 2.0 ...
  • Page 11 SCU224 Maximum temperature limitation Minimum and maximum temperature limits can be set for the heat exchange function. The maximum temperature limitation uses sensor 4 as MX3O / MX3F: reference sensor. Maximum temperature limitation Adjustment range: The maximum temperature limitation function provides 30.0 ...

  • Page 12: System Layout 3

    SCU224 System layout 3 The controller calculates the temperature difference bet- rates relay 2 for backup heating or heat dump purposes, ween collector sensor S1 and tank sensor S2. If the diffe- when the adjusted thermostat switch-on temperature rence is larger than or identical to the adjusted switch-on (AH O) is reached.
  • Page 13 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 14: System-Specific Functions

    SCU224 The following functions are exclusively available in system System-specific functions layout 3. The corresponding channels will not be available in any other system layout. Thermostat function The thermostat function works independently from the Backup heating solar operation and can be used for using surplus energy or for backup heating.
  • Page 15 SCU224 Option: Thermal disinfection of the upper DHW zone (OTD) OTD: This function is used for protecting the upper tank zone Thermal disinfection function against Legionella by activating the backup heating. Adjustment range: ON / OFF Reference sensor for the thermal disinfection is S3! Factory setting: OFF Î...

  • Page 16: System Layout 4

    SCU224 System layout 4 The controller calculates the temperature differences tures (S1MX / S2MX) are reached. The priority logic causes between collector sensor S1 and tank sensors S2 and S3. If priority loading of the upper zone of the tank, if possible.
  • Page 17 SCU224 Adjustment Channels Channel Description Factory setting Page System Minimum pump speed 30 % DT1O Switch-on temperature difference 1 12.0 °Ra [6.0 K] DT1F Switch-off temperature difference 1 8.0 °Ra [4.0 K] DT1S Nominal temperature difference 1 20.0 °Ra [10.0 K]...

  • Page 18: System Layout 5

    SCU224 System layout 5 The controller calculates the temperature differences S2MX) are reached. The priority logic causes priority loading between collector sensor S1 and tank sensors S2 and S3. If of tank 1, if possible. For loading tank 2 the 3-way-valve will the differences are larger than or identical to the adjusted be operated by relay 2.
  • Page 19 SCU224 Adjustment Channels Channel Description Factory setting Page System Minimum pump speed 30 % DT1O Switch-on temperature difference 1 12.0 °Ra [6.0 K] DT1F Switch-off temperature difference 1 8.0 °Ra [4.0 K] DT1S Nominal temperature difference 1 20.0 °Ra [10.0 K]...

  • Page 20: System Layout 6

    SCU224 System layout 6 The controller calculates the temperature differences tank temperatures (S1MX / S2MX) are reached. The priority between collector sensor S1 and tank sensors S2 and S3. If logic causes priority loading of the selected tank (PRIO), if the differences are larger than or identical to the adjusted possible.
  • Page 21 SCU224 Adjustment Channels Channel Description Factory setting Page System DT1O Switch-on temperature difference 1 12.0 °Ra [6.0 K] DT1F Switch-off temperature difference 1 8.0 °Ra [4.0 K] DT1S Nominal temperature difference 1 20.0 °Ra [10.0 K] RIS1 Rise control R1 4 °Ra [2 K]...

  • Page 22: System Layout 7

    SCU224 System layout 7 The controller calculates the temperature differences relay 2, and the tank will be loaded until the switch-off between the collector sensors S1 and S3 and the tank temperature difference (DT F) or the maximum tank tem- sensor S2.
  • Page 23 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 / R2 4 °Ra [2 K]...

  • Page 24: System Layout 8

    SCU224 System layout 8 The controller calculates the temperature difference bet- A solid fuel boiler will be operated by relay 2, if the tempera- ween collector sensor S1 and tank sensor S2. If the diffe- ture difference between sensors S4 and S3 is larger than or...
  • Page 25 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 26: System-Specific Functions

    SCU224 System-specific functions The following adjustments are used for the specific functions in system layout 8. ∆T control for backup heating by solid fuel boiler Reference sensors for this function are S4 and S3. In system layout 8, the controller is equipped with an ad-...
  • Page 27 SCU224 Maximum temperature limitation Minimum and maximum temperature limits can be set for the solid fuel boiler. MX3O / MX3F: The maximum temperature limitation function provides a Maximum temperature limitation maximum tem perature setting, usually to reduce scald risk Adjustment range: in a storage tank.

  • Page 28: System Layout 9

    SCU224 System layout 9 The controller calculates the temperature difference bet- A heating circuit return preheating will be operated by ween collector sensor S1 and tank sensor S2. If the diffe- relay 2, if the temperature difference between sensors S3...
  • Page 29 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 30: System Layout 10

    SCU224 System layout 10 The controller calculates the temperature difference bet- will be operated by relay 2 in order to direct the surplus ween collector sensor S1 and tank sensor S2. If the diffe- energy to a heat dump. For security purpose this will be...
  • Page 31 SCU224 Adjustment Channels Channel Description Factory setting Page System DT O Switch-on temperature difference 12.0 °Ra [6.0 K] DT F Switch-off temperature difference 8.0 °Ra [4.0 K] DT S Nominal temperature difference 20.0 °Ra [10.0 K] Rise control R1 4 °Ra [2 K]...

  • Page 32: Operation And Function

    SCU224 2. Operation and function The controller is operated via three push buttons below the display. Button 1 is used for scrolling forward through the 2.1 Push buttons indication menu or to increase the adjustment values. But- ton 2 is used for scrolling backward and reducing values.

  • Page 33: Flashing Codes

    SCU224 System screen The system screen (active system layout) shows the system selected on the controller. It consists of several system component symbols, which are – depending on the current status of the system – either flashing, permanently shown or hidden.

  • Page 34: Commissioning

    SCU224 3. Commissioning Î Establish the power supply During a short initialization phase, the operating control lamp flashes red and green. When the controller is commissioned for the first time or after a reset, it will run a commissioning menu. The...
  • Page 35 SCU224 Arr: 4. System layout System layout selection Î Adjust the desired system layout of your solar thermal Adjustment range: 1 ... 10 system Factory setting: 1 For a detailed description of the different system layouts selectable, see chapter 1.4.
  • Page 36 SCU224 S MX / S1MX / S2MX: 5. Maximum tank temperature Maximum tank temp. Î Adjust the desired maximum tank temperature Adjustment range: 40 ... 200 °F [4 ... 95 °C] Note: Arr 10: The controller is also equipped with a non- 40 ...

  • Page 37: Channel Overview

    SCU224 4. Channel overview 4.1 Display channels Note: The displayed values and adjustment channels depend on which system layout, which options and functions have been selected. Only values and adjustment channels available for the indivi- Indication of drainback time periods dual settings selected will appear in the menu.
  • Page 38 SCU224 Indication of current pump speed Indicates the current pump speed of the corresponding pump. n %, n1 %, n2 %: • n % : current pump speed (1-pump system) Current pump speed • n1 % : current pump speed pump 1 Display range: 30 ...

  • Page 39: Adjustment Channels

    SCU224 4.2 Adjustment channels In this channel, a pre-defined system layout can be selected. System layout selection Each system layout has a set of pre-programmed settings Arr: that can be individually changed. System layout selection. If the system layout selection is changed later on, all adjust- Adjustment range: 1 ...
  • Page 40 SCU224 Maximum tank temperature Once the adjusted maximum temperature is exceeded, S MX / S1MX / S2MX: the solar pump is switched off and further loading of the Maximum tank temp. tank is prevented to reduce scald risk or system damage. A Adjustment range: fixed hysteresis of 4 °Ra [2 K] is set for the maximum tank...
  • Page 41 SCU224 Cooling functions In the following the three cooling functions – collector cooling, system cooling and tank cooling – are described in detail. The following notes are valid for all three cooling functions: Note: The cooling functions will not become active as long as solar loading is possible.
  • Page 42 SCU224 Tank cooling function When the tank cooling function is activated, the controller aims to cool down the tank during the night in order to OSTC: prepare it for solar loading on the following day. Tank cooling option If the adjusted maximum tank temperature (S MX / S1MX)
  • Page 43 SCU224 If a multi-tank system layout has been chosen, the priority The SCU224 priority logic logic determines how the heat is divided between the Note: tanks. Different types of priority logic are adjustable: Priority logic can be used in multi-tank system •...
  • Page 44 SCU224 Evacuated tube collector function O TC: This function helps overcome the disadvantages caused by Evacuated tube collector the non-ideal sensor position with some tube collectors. function This function is not required with the Vitosol 300-T, but is Adjustment range: OFF / ON required for the Vitosol 200-T.
  • Page 45 Drainback option Note: A drainback system permits the heat transfer fluid to drain Viessmann Vitosol collectors cannot be used in back into the holding tank when solar energy is not coll- drainback systems. ected. The drainback option will initiate the filling of the system when solar loading begins.
  • Page 46 SCU224 Operating mode For control and service work, the operating mode of the controller can be manually adjusted. For this purpose, select MAN1 / MAN2: the adjustment value MAN1, MAN2 in which the following Operating mode adjustments can be made:...

  • Page 47: Troubleshooting

    SCU224 5. Troubleshooting fuse In the case of an error, a message is shown on the display of the controller: Warning symbols Operating control lamp VBus terminals ® sensor terminals load terminals ground terminals power supply terminals Operating control lamp flashes red. On the display the Operating control lamp off.

  • Page 48: Various

    SCU224 5.1 Various: Pump is overheated, but no heat transfer from the Pump starts for a short moment, switches off, switches collector to the tank, flow and return have the same tem- on again, etc. perature; perhaps also air / gas bubbles in the lines.
  • Page 49 SCU224 Tanks cool down at night Control the non-return Further pumps which are valve in warm water cir- connected to the solar culation - o.k. tank must also be che- cked. Collector circuit pump runs during the night? Check controller:...

  • Page 50: Accessories

    SCU224 6. Accessories 6. Accessories Smart Display SD3 The Smart Display is designed for simple connection to controllers with VBus ® . It is used for visualizing data issued by the controller: collector temperature, storage temperature and energy yield of the solar thermal system. The use of high-efficient LEDs and filter glass assures a high optical brilliance and good readability even in poor visibility conditions and from a larger distance.
  • Page 51 SCU224 Notes...

  • Page 52: Impressum

    As faults can never be excluded, please note: Your own calculations and plans, under con sider- approval of Viessmann Manufacturing Company Inc.. This es- ation of the current standards should only be basis for your pecially applies for copies, translations, microfilms and the projects.

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