SCU224 Mounting Connection Application examples Operation 49011100 *49011100* SCU224 Troubleshooting en-US/CA 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.
SCU224 Contents General...................................................................... 2 Overview.................................................................... 3 1. Installation............................................................ 4 1.1 Mounting.................................................................................4 1.2 Electrical connection............................................................4 1.3 Data communication/ Bus..................................................
SCU224 Overview • System-monitoring-display • Up to 4 Pt1000 temperature sensors • 2 semiconductor relays for pump speed control • 10 basic system layouts to choose from • Energy metering • VBus® • Function control • Thermostat function (time controlled) • Control of the system by ServiceCenter software possible ! • User-friendly operation • Housing with outstanding design • Extra-low power consumption 1 × accessory bag 1 × spare fuse T4A 2 × screws and wall plugs 4 × strain relief and screws 6
SCU224 1. Installation 1.1 Mounting WARNING! Electric shock! Opening the housing will expose live parts! ÎÎ Switch off power supply and disconnect the device from power supply before opening the housing! display push button cover cable conduits with strain relief fuse 4A upper fastening . „ lower fastening 1.
SCU224 R1 1 (1) A (100 ... 240) V~ R2 1 (1) A (100 ... 240) V~ 12 13 14 N R2 N R1 N L 15 16 17 18 19 20 Grounding and load terminals Temp. Sensor Pt1000 S1 1 2 3 S2 4 S3 5 6 S4 7 8 Sensor terminals S1 ... S4 1.3 Data communication/ Bus © Viessmann 5443203 VBus® connection terminals 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!).
SCU224 1.4 Terminal allocation in the different system layouts System layout 1 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 nMN x Minimum pump speed S MX x Maximum tank temperature Emergency temperature collector EM x Emergency temperature collector if ODB is activated: OCC x Option collector cooling CMX x* Maximum collector temperature OSYC x Option system cooling DTCO x* Cooling switch-on temperature difference DTCF x* Cooling sw
SCU224 System layout 2 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 n1MN x Minimum pump speed R1 S MX x Maximum tank temperature n2MN s Minimum pump speed R2 Emergency temperature collector EM x Emergency temperature collector if ODB is activated: OCC x Option collector cooling CMX x* Maximum collector temperature OSYC x Option system cooling DTCO x* Cooling switch-on temperat
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 DT3O: Switch-on temperature diff. Adjustment range: 2.0 ... 40.0°Ra [1.0 ... 20.0 K] in steps of 1 °Ra [0.5 K] Factory setting: 12.0°Ra [6.0 K] DT3F: Switch-off temperature diff. Adjustment range: 1.0 ... 39.0°Ra [0.5 ... 19.5 K] in steps of 1 °Ra [0.5 K] Factory setting: 8.0°Ra [4.
SCU224 Maximum temperature limitation MX3O / MX3F: Maximum temperature limitation Adjustment range: 30.0 ... 200.0 °F [0.0 ... 95.0 °C] in steps of 1 °Ra [0.5 K] Factory setting: MX3O: 140.0 °F [60.0 °C] MX3F: 136.0 °F [58.0 °C] Minimum temperature limitation MN3O / MN3F: Minimum temperature limitation Adjustment range: 30.0 ...190.0 °F [0.0 ... 90.0 °C] in steps of 1 °Ra [0.5 K] Factory setting (Arr = 2 only): MN3O: 40.0 °F [5.0 °C] MN3F: 50.0 °F [10.
SCU224 System layout 3 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 n1MN x Minimum pump speed R1 S MX x Maximum tank temperature Emergency temperature collector EM x Emergency temperature collector if ODB is activated: OCC x Option collector cooling CMX x* Maximum collector temperature OSYC x Option system cooling DTCO x* Cooling switch-on temperature difference DTCF x* Coolin
SCU224 System-specific functions The following functions are exclusively available in system layout 3.The corresponding channels will not be available in any other system layout. Thermostat function Backup heating The thermostat function works independently from the solar operation and can be used for using surplus energy or for backup heating.
SCU224 Option:Thermal disinfection of the upper DHW zone (OTD) OTD: Thermal disinfection function Adjustment range: ON / OFF Factory setting: OFF PDIS: Monitoring period Adjustment range: 0 ... 30:0 ... 24 h (dd:hh) Factory setting: 01:00 DDIS Heating period Adjustment range: 00:00 ... 23:59 (hh:mm) Factory setting: 01:00 TDIS Disinfection temperature Adjustment range: 30 ... 200 °F [0 ...
SCU224 System layout 4 The controller calculates the temperature differences between collector sensor S1 and tank sensors S2 and S3. If the differences are larger than or identical to the adjusted switch-on temperature differences (DT1O / DT2O), the solar pump will be operated by relay 1, and the respective tank zone will be loaded until the switch-off temperature differences (DT1F / DT2F) or the maximum tank tempera- tures (S1MX / S2MX) are reached.
SCU224 Adjustment Channels Channel Description Arr x System nMN x Minimum pump speed DT1O x Switch-on temperature difference 1 DT1F x Switch-off temperature difference 1 DT1S x Nominal temperature difference 1 RIS1 x Rise control R1 S1 MX x Maximum temperature tank 1 DT2O x Switch-on temperature difference 2 DT2F x Switch-off temperature difference 2 DT2S x Nominal temperature difference 2 RIS2 x Rise control R2 S2MX x Maximum temperature tank 2 EM x Emergency temperature collector OCC x Option collector co
SCU224 System layout 5 The controller calculates the temperature differences between collector sensor S1 and tank sensors S2 and S3. If the differences are larger than or identical to the adjusted switch-on temperature differences (DT1O / DT2O), the solar pump will be operated by relay 1, and the respective tank will be loaded until the switch-off temperature differences (DT1F / DT2F) or the maximum tank temperatures (S1MX / S2MX) are reached.
SCU224 Adjustment Channels Channel Description Arr x System nMN x Minimum pump speed DT1O x Switch-on temperature difference 1 DT1F x Switch-off temperature difference 1 DT1S x Nominal temperature difference 1 RIS1 x Rise control R1 S1 MX x Maximum temperature tank 1 DT2O x Switch-on temperature difference 2 DT2F x Switch-off temperature difference 2 DT2S x Nominal temperature difference 2 RIS2 x Rise control R2 S2MX x Maximum temperature tank 2 EM x Emergency temperature collector OCC x Option collector co
SCU224 System layout 6 The controller calculates the temperature differences between collector sensor S1 and tank sensors S2 and S3. If the differences are larger than or identical to the adjusted switch-on temperature differences (DT1O / DT2O), the solar pumps will be operated by relay 1 and / or relay 2, and the respective tank will be loaded until the switch-off temperature differences (DT1F / DT2F) or the maximum tank temperatures (S1MX / S2MX) are reached.
SCU224 Adjustment Channels Channel Description Arr x System DT1O x Switch-on temperature difference 1 DT1F x Switch-off temperature difference 1 DT1S x Nominal temperature difference 1 RIS1 x Rise control R1 n1MN x Minimum pump speed R1 S1 MX x Maximum temperature tank 1 DT2O x Switch-on temperature difference 2 DT2F x Switch-off temperature difference 2 DT2S x Nominal temperature difference 2 RIS2 x Rise control R2 n2MN x Minimum pump speed R2 S2MX x Maximum temperature tank 2 EM x Emergency temperature co
SCU224 System layout 7 The controller calculates the temperature differences between the collector sensors S1 and S3 and the tank sensor S2. If the differences are larger than or identical to the adjusted switch-on temperature difference (DT O), the respective solar pump will be operated by relay 1 and / or relay 2, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached. Sensor S4 can optionally be connected for measurement purposes.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 / R2 n1MN x Minimum pump speed R1 S MX x Maximum tank temperature n2MN x Minimum pump speed R2 EM1 x Emergency temperature collector EM2 x Emergency temperature collector OCC1 x Option collector cooling collector 1 CMX1 x* Maximum temperature collector 1 OCC2 x Option collector cooling collector 2 CMX2 x* Maxi
SCU224 System layout 8 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 n1MN x Minimum pump speed R1 S MX x Maximum tank temperature n2MN s Minimum pump speed R2 Emergency temperature collector EM x Emergency temperature collector if ODB is activated: OCC x Option collector cooling CMX x* Maximum collector temperature OSYC x Option system cooling DTCO x* Cooling switch-on temperat
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 additional differential control for heat exchange from a solid fuel boiler (e.g. woodstove). The basic differential function is adjusted using the switch-on (DT3O) and switch-off (DT3F) temperature differences.
SCU224 Maximum temperature limitation MX3O / MX3F: Maximum temperature limitation Adjustment range: 30.0 ... 200.0 °F [0.0 ... 95.0 °C] in steps of 1 °Ra [0.5 K] Factory setting: MX3O: 140.0 °F [60.0 °C] MX3F: 136.0 °F [58.0 °C] Minimum temperature limitation MN3O / MN3F: Minimum temperature limitation Adjustment range: 30.0 ...190.0 °F [0.0 ... 90.0 °C] in steps of 1 °Ra [0.5 K] Factory setting (Arr = 8 only): MN3O: 140.0 °F [60.0 °C] MN3F: 150.0 °F [65.
SCU224 System layout 9 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 nMN x Minimum pump speed S MX x Maximum tank temperature Emergency temperature collector EM x Emergency temperature collector if ODB is activated: OCC x Option collector cooling CMX x* Maximum collector temperature OSYC x Option system cooling DTCO x* Cooling switch-on temperature difference DTCF x* Cooling sw
SCU224 System layout 10 The controller calculates the temperature difference between collector sensor S1 and tank sensor S2. If the difference is larger than or identical to the adjusted switch-on temperature difference (DT O), the solar pump will be operated by relay 1, and the tank will be loaded until the switch-off temperature difference (DT F) or the maximum tank temperature (S MX) is reached.
SCU224 Adjustment Channels Channel Description Arr x System DT O x Switch-on temperature difference DT F x Switch-off temperature difference DT S x Nominal temperature difference RIS x Rise control R1 nMN x Minimum pump speed S MX x Maximum tank temperature EM x Emergency temperature collector CMX s Maximum collector temperature OCN x Option minimum limitation CMN x* Minimum collector temperature OCF x Option antifreeze CFR x* Antifreeze temperature O TC x Option tube collector TCST x* OTC starting time TCE
SCU224 2. Operation and function 2.1 Push buttons operating control lamp forward backward 2 3 1 SET (selection / adjustment mode) 2.2 System monitoring display ! system monitoring display channel display The controller is operated via three push buttons below the display. Button 1 is used for scrolling forward through the indication menu or to increase the adjustment values. Button 2 is used for scrolling backward and reducing values.
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.
SCU224 3. Commissioning 2 3 1 (SET) The three pushbuttons of the BS Plus controller ÎÎ 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 commissioning menu leads the user through the most important adjustment channels needed for operating the system.
SCU224 Arr: System layout selection Adjustment range: 1 ... 10 Factory setting: 1 4. System layout ÎÎ Adjust the desired system layout of your solar thermal system For a detailed description of the different system layouts selectable, see chapter 1.4.
SCU224 S MX / S1MX / S2MX: Maximum tank temp. Adjustment range: 40 ... 200 °F [4 ... 95 °C] Arr 10: 40 ... 190 °F [4 ... 90 °C] in steps of 2 °Ra [1 K] Factory setting:140 °F [60 °C] 5. Maximum tank temperature ÎÎ Adjust the desired maximum tank temperature nMN, n1MN, n2MN: Pump speed control Adjustment range: 30 ...100 in steps of 5 % Factory setting: 30 6.
SCU224 4. Channel overview 4.1 Display channels Indication of drainback time periods Initialization 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 individual settings selected will appear in the menu. Indicates the time adjusted in tDTO, running backwards. INIT: ODB initialization active Filling time Indicates the time adjusted in tFLL, running backwards.
SCU224 n %, n1 %, n2 %: Current pump speed Display range: 30 ...100 % kWh/MWh: Heat quantity in kWh / MWh Display channel Indicates the current pump speed of the corresponding pump. • n % : current pump speed (1-pump system) • n1 % : current pump speed pump 1 • n2 % : current pump speed pump 2 Indicates the energy gained in heat quantity – only available if energy metering (OHQM) is activated.
SCU224 4.2 Adjustment channels System layout selection Arr: System layout selection. Adjustment range: 1 ... 10 Factory setting: 1 Security enquiry: In this channel, a pre-defined system layout can be selected. Each system layout has a set of pre-programmed settings that can be individually changed. If the system layout selection is changed later on, all adjustments made in the other channels will be lost. Therefore, changing the system layout is always followed by a security enquiry.
SCU224 Maximum tank temperature S MX / S1MX / S2MX: Maximum tank temp. Adjustment range: 40 ... 200 °F [4 ... 95 °C] Arr 10: 40 ... 190 °F [4 ... 90 °C] in steps of 2 °Ra [1 K] Factory setting:140 °F [60 °C] Collector temperature limitation Emergency shutdown of the collector EM / EM1 / EM2: Collector temperature limitation Adjustment range: 170 ... 390 °F [80 ...
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. Note: In 2-tank-systems, the cooling functions will only affect tank 1, respectively the bottom area of the tank (such as in Arr = 4).
SCU224 OSTC: Tank cooling option Adjustment range: OFF / ON Factory setting: OFF OHOL: Holiday cooling option Adjustment range: OFF / ON Factory setting: OFF THOL: Holiday cooling temperature Adjustment range: 70 ... 175 °F [20 ... 80 °C] in steps of 1 °F [1 °C] Factory setting: 110 °F [40 °C] Collector minimum limitation option OCN / OCN1 / OCN2: Collector minimum limitation Adjustment range: OFF / ON Factory setting: OFF CMN / CMN1 / CMN2: Collector minimum temp. Adjustment range: 50 ...190 °F [10 ...
SCU224 The SCU224 priority logic Note: Priority logic can be used in multi-tank system layouts only (Arr = 4, 5, 6). PRIO: Loading priority Adjustment range: SE 1, SE 2, Su 1, Su 2, 0, 1, 2 Factory setting: Arr 4: 2 Arr 5, 6: 1 Note: If the priority is set to Su 1 or Su 2, solar loading of the subordinate tank will be aborted at once if the temperature in the priority tank (tank 1 for Su 1, tank 2 for Su 2) falls below the adjusted maximum temperature.
SCU224 Evacuated tube collector function TCST: Tube collector function starting time Adjustment range: 00:00 ...23:45 in steps of 00:15 Factory setting: 07:00 TCEN: Tube collector function ending time Adjustment range: 00:00 ...23:45 in steps of 00:15 Factory setting: 19:00 TCRU: Tube collector function runtime Adjustment range: 5 ... 500 s in steps of 5 s Factory setting: 30 s TCIN: Tube collector function standstill interval Adjustment range: 1 ...
SCU224 Drainback option Note: Viessmann Vitosol collectors cannot be used in drainback systems. Note: A drainback system layout requires additional components such as a holding tank.The drainback option should only be activated if all components required are properly installed. Note: The drainback option is only available in system layouts with one tank and one collector (Arr 1, 2, 3, 8 and 9).
SCU224 Operating mode MAN1 / MAN2: Operating mode Adjustment range: OFF, Auto, ON Factory setting: Auto For control and service work, the operating mode of the controller can be manually adjusted.
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 ground terminals load terminals power supply terminals Operating control lamp flashes red. On the display the symbols and appear. Sensor defect. An error code instead of a temperature is displayed in the sensor display channel. 888.8 Short circuit. Check cable.
SCU224 5.1 Various: Pump is overheated, but no heat transfer from the collector to the tank, flow and return have the same temperature; perhaps also air / gas bubbles in the lines. Pump starts for a short moment, switches off, switches on again, etc. Air in the system? Temperature difference at the controller too small? no yes Is the collector circuit blocked at the dirt trap? Air in the system; increase the system pressure to at least static primary pres sure plus 7. 25 psi (0.
SCU224 a Tanks cool down at night b Control the non-return valve in warm water circulation - o.k. Collector circuit pump runs during the night? no yes Collector temperature is at night higher than the outdoor temperature no yes Sufficient tank insulation? yes no Check controller: Manual operation active? Tube collector function active? Tank cooling or antifreeze function active? Check the check valve in the flow and the return pipe with regard to the functional efficiency. Increase insulation.
SCU224 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. An additional power supply is not required.
© Viessmann 5443203 SCU224 Notes 51 |
Viessmann Manufacturing Company (U.S.) Inc. 45 Access Rd. Warwick, RI 02886 Telephone: (401) 732-0667 Fax: (401) 732-0590 Internet: www.viessmann-us.com E-Mail: info@viessmann-us.com Viessmann Manufacturing Company Inc. 750 McMurray Rd. Waterloo, Ontario N2V 2G5 Telephone: (519) 885-6300 Fax: (519) 885-0887 Internet: www.viessmann.ca E-Mail: mail@viessmann.ca Important notice: The texts and drawings in this manual are correct to the best of our knowledge.
