Produkt-Datenblatt

3 344 Differential Temperature Controller RWD32S Differential temperature controller for solar storage systems. Panel mounting design. Two 2-position control outputs AC 24…230 V. Use Plant types Solar energy plants with one or two storage tanks Swimming pool heating systems with solar panels Building types Residential buildings of all types Non-residential buildings of all types Features Standalone electronic temperature controller Operating voltage AC 230 V Three inputs for LG-Ni 1000, Pt 1000 temperature sensors.

Unit can be set as °C or °F One digital input for ON/OFF mode change-over Two 2-position outputs Entering or changing of all data via operating buttons on the controller, without addi- tional tools PC connection for uploading / downloading applications and parameters, via the software tool (option) CE2N3344en 25.11.2009 Building Technologies

Page 1

Functions Control of the adjusted temperature differential through 2-position outputs for one or two devices Main functions Pre-configured application types selectable Changeover to a secondary heat source upon demand (depending on application) Energy savings counter Minimum charging temperature Other functions Absolute temperature setpoint Maximum tank temperature limitation Frost protection Gradient function Adjustable time delay for ON/OFF outputs Ordering When ordering, please give type reference: Description, scope of delivery Type reference Temperature differential controller RWD32S Equipment combinations Controlled devices The following types of devices can be controlled:

2-position actuators On/Off actuating devices of all types Controlled devices must have control contacts suited for AC 24…230 V, 4 A. All types of temperature sensors using a sensing element LG-Ni 1000 Ω at 0 °C, or Pt 1000 can be used for the external signals (B1, B2 and B3). For example: Temperature sensors All sensors connected to the controller must have the same sensing element type. Accessories Product documentation Technical design Basic Control The controller switches its control output when the set temperature differential (set- point) is reached. The following settings are required:

2/12 Siemens Differential Temperature Controller RWD32S CE2N3344en Building Technologies 26.11.2009 Type of sensor Type reference Data Sheet Strap-on temperature sensor Ni 1000 QAD22 N1801 Immersion temperature sensor Ni 1000 QAE2120.. N1781 Solar panel sensor Ni 1000 QAP21.2 N1833 Cable temperature sensor Ni 1000 QAP21.3 N1831 Cable temperature sensor Pt 1000 QAP2012.150 N1831 Name Type reference Protective small enclosure for wall mounting ARG62.21 Document type Classification number Installation instructions G3344 Declaration of Conformity (CE) T3344 Environmental Declaration E3344

Page 2

The setpoint, that is, the temperature differential required between the 2 plant com- ponents or sections The switching differential The switching delay Two temperature sensors (B1, B2) are used to measure the heat source differential temperature. 3337D01 ON OFF ΔT Differential temperature ΔTw Differential temperature setpoint ΔT ON Switch-ON point ΔT OFF Switch-OFF point SD Switching differential T [K] T OFF T ON Tw If the source temperature (B2) exceeds the consumer temperature (B1) by the switch- ON point (ΔT ON = ΔT W + Ѕ SD), the controller closes its control contact Q11–Q14, thus switching the actuating device ON.

If this difference falls below the switch-OFF point (ΔT OFF = ΔT W – Ѕ SD), the controller closes its control contact Q11–Q12, thus switch- ing OFF the actuating device. Minimum charging temperature On the controller, a minimum charging temperature can be set. The controller switches its control output only when the differential temperature setpoint (ΔT W ) and the minimum external temperature (B2) are reached. Below these tempera- ture levels, the output is switched OFF with a fixed switching differential of 4 K. When the limitation is active, the limit icon “LIM” is displayed on all screens and symbol ” on B2 screen.

To disable this function, the parameter “ B2 ” must be set to value OFF (refer to docu- ment “Installation instructions”). Absolute setpoint temperature With application types 2, 3 and 4 , an absolute temperature can also be set. Application 2 : The controller switches its output ON (control contact Q21–Q24) when the temperature measured by sensor B3 falls below the value set. The output is switched OFF again (control contact Q21–Q22) when the temperature exceeds the setpoint by a switching differential of 1…10 K Application 3 and 4 : The controller switches its output ON (control contact Q21– Q24) when the temperature measured by sensor B3 exceeds the value set.

The out- put is switched OFF again (control contact Q21–Q22) when the temperature falls down under the setpoint by a switching differential of 1…10 K Maximum temperature limitation A maximum temperature can also be set. When the temperature measured by sensor (B3 or B1) reaches the limit value set, the controller closes its control contact (Q11– Q12), thus switching the actuating device off . When this temperature falls below the setpoint by a fixed switching differential of 10 K, the controller closes its control contact (Q11–Q14) and the actuating device is switched back ON again.

When the limitation is active, the limit icon “LIM” is displayed on all screens and symbol ” on B3 or B1 screen. To disable this function, the parameter “Maximum charging temperature” must be set to value OFF (refer to document “Installation instructions”). Siemens Differential Temperature Controller RWD32S CE2N3341en Building Technologies 26.11.2009 3/12

Page 3

Frost protection If the temperature of the solar collector (B2) drops below 5 °C, the pump is switched on and the icon “Fr” is displayed, blinking on all screens. When collector temperature drops above 10 °C, the pump is switched off. To disable this function, the parameter “FROST” must be set to value OFF (refer to document “Installation instructions”). The pump must periodically be switched on, as the temperature at the collector (primar- ily vacuum pipes) cannot be measured reliably when the pump is off. Gradient function If pump is not switched on during more than 30 minutes or “OFF mode” activated, the controller switches on the pump during 30 seconds every 30 minutes.

To disable this function, the parameter “GRAD” must be set to value OFF (refer to document “Installation instructions”). Energy saving counter The controller displays the cumulated energy savings done by the plant since first start or last counter reset. Calculated cost saving value (local currency not displayed) is based on parameters set during commissioning by customer: Pump flow rate (m 3 /h) indicated on pump plate Cost (local currency / kWh) of energy chosen as reference (i.e. gas, electricity) When “OFF mode” is activated with an external command as time switch or manual switch, on dedicated controller input (D1–GND), the internal control loop is disabled.

OFF Mode As long as this mode is activated, only minimal functions remain active (Frost protection and gradient function). During “OFF Mode”, pump can be switched on by controller functions as “Frost protec- tion” or “Gradient function”. These functions can be disabled if necessary (refer to docu- ment “Installation instructions”). Mechanical design Housing The controller is designed for mounting in a wall or a cabinet. The product set RWD32S is as per DIN 43 880 Gr. 1 requirements. The housing is made of plastic and accommodates the controller electronics and all operating elements, which are accessible into the front of the controller. The front car- ries three buttons and an LCD display.

Protective housings ARG62.21 A protective housing is used to protect the controller when mounted outside a control panel, such as on ducts, walls and in plant rooms. Furthermore, the protective hous- ing prevents inadvertent contact with voltage supplying parts such as the connecting terminals. The RWD32S controller clips on a DIN rail into the protective housing. Cable entries are located at the top and the bottom of the protective housing. Front has an opening for the LCD display and the programming buttons. Operating and display elements The RWD32S is operated by the buttons on the controller front. Additional tools are not necessary.

A 9-pin port is provided for optional programming via the software tool. 4/12 Siemens Differential Temperature Controller RWD32S CE2N3344en Building Technologies 26.11.2009

Page 4