Technical Data Manual Model Nos. and pricing: see Price List For operation with natural gas and liquid propane gas Floor mounted, gas-fired condensing boiler Heating input 19 to 199 MBH 5.6 to 58 kW VITOCROSSAL 300 Product may not be exactly as shown Vitocrossal 300 CU3A Series 26 to 57 Floor mounted, gas-fired condensing boiler with modulating MatriX gas burner. For room air dependent or independent operation.
Product Information Vitocrossal 300 CU3A 26 to 57 Technical Data Benefits Equipped with the industry’s first intelligent combustion management system and powerful control technology, the new generation Vitocrossal 300 CU3A gas-fired Floor mounted condensing boiler delivers unparalleled performance, reliability and comfort. The benefits at a glance: ■ Best value in its class with new industry-leading technology and the most standard features.
Vitocrossal 300 CU3A 26 to 57 Technical Data Product Information Cross-Section Vitocrossal 300 CU3A 26 to 57 Vitocrossal 300 CU3A boiler efficiency dependent on system heating water return temperatures and load conditions Product may not be exactly as shown 5673 647 - 03 Legend A Digital Vitotronic boiler control unit B Water-cooled stainless steel combustion chamber C Modulating MatriX gas burner – for extremely clean combustion D Stainless steel Inox-Crossal heat exchanger E Highly effective thermal
Technical Data Vitocrossal 300 CU3A 26 to 57 Technical Data Technical Data Boiler Model No. CU3A Natural Gas / Liquid Propane Gas CSA input MBH (kW) MBH (kW) 26 35 45 57 25-125 (7.3-36.6) 23.3-116 (6.8-34) 101 (30) 43-160 (12.6-47) 40-149 (11.7-43.7) 129 (38) 43-199 (12.6-58) 40-185 (11.7-54.2) 161 (47) Net AHRI Rating MBH (kW) 19-94 (5.6-27.5) 17.7-87 (5.2-25.5) 76 (22) Heat exchanger surface area ft.2 (m2) 16.7 (1.5) 20.7 (1.9) 34.1 (3.2) 34.1 (3.2) “w.c. “w.c.
Technical Data Vitocrossal 300 CU3A 26 to 57 Technical Data Technical Data Boiler Model No. CU3A Dimensions Overall depth Overall width Overall height (with control interface open) Overall height Flue gas *4 Temperature (at boiler return temperature of 86ºF (30ºC) - at rated full load - at rated partial load Temperature (at boiler return temperature of 140ºF (60ºC) Max.
Dimensional Information Vitocrossal 300 CU3A 26 to 57 Technical Data Models 300 CU3A 26 to 57 Legend A Overall boiler height (boiler control open) B Overall boiler height (boiler control closed) C Safety header connection D Boiler supply E Gas connection F Boiler return G Boiler drain H Vent connection I Condensate drain connection J Combustion air connection Model 26 to 35 Model 45 and 57 a in. (mm) 27 (684) a in. (mm) 31b (801) b in. (mm) 17 (430) b in. (mm) 21b (545) c in.
Minimum Clearances Vitocrossal 300 CU3A 26 to 57 Technical Data Recommended Minimum Service Clearances Note: The Vitocrossal 300 CU3A series boiler conforms to the zero inches vent clearance to combustibles testing requirements dictated by the boiler Harmonized Standard ANSI Z21.13. CSA/4.9 and therefore is listed for zero clearance to combustibles when vented with a single-wall UL/ ULC certified special venting system.
Waterside Flow Vitocrossal 300 CU3A 26 to 57 Technical Data Pressure drop Pressure Drop (heating water side) Flow rate Legend A Boiler models CU3A 26 to 35 kW B Boiler models CU3A 45 to 57 kW The Vitocrossal 300 is only suitable for fully pumped hot water heating systems. Boiler models CU3A ∆T = 20ºF (10 K) ∆T = 30ºF (15 K) ∆T = 40ºF (20 K) Flow rate USGPM (m3/h) Flow rate USGPM (m3/h) Flow rate USGPM (m3/h) 26 9.9 (2.2) 6.6 (1.5) 4.9 (1.1) 35 13.3 (3.0) 8.9 (2.0) 6.6 (1.5) 45 17.0 (3.
Boiler Control Vitocrossal 300 CU3A 26 to 57 Technical Data On-Board Vitotronic 200, HO1B Control Modular structure 5673 647 - 03 The control unit is integrated into the boiler. The control unit comprises a standard unit, electronics modules and a programming unit.
Boiler Control Vitocrossal 300 CU3A 26 to 57 Technical Data Design and Function ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ Weather-compensated control of the boiler water and/or supply temperature Control of one heating circuit without mixer and two heating circuits with mixer (with accessory mixing valve extension modules) Demand-dependent heating circuit pump and burner off control Adjustment of a variable heating limit Anti-seizing pump protection Integral diagnostic system Maintenance display DHW temperature control wit
Vitocrossal 300 CU3A 26 to 57 Technical Data Design and Functions (continued) Technical Data Rated supply voltage: Rated frequency: Rated current: Max. ambient temp. - at operation: 120VAC 60 Hz Less than 12 A 32 to 104ºF (0 to 40ºC) Installation in living spaces or boiler rooms (standard ambient conditions) - when storing or transporting: Max. operating temp.
Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data Sensors Boiler Temperature Sensor (supplied) The boiler temperature sensor is connected at the control unit for weather-responsive operation and is built into the boiler. Outdoor Temperature Sensor (supplied) Specification sensor type: Viessmann NTC 10K ohms at 77ºF (25ºC) Max. ambient temp.
Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data Optional Accessories (continued) Room Temperature Sensor, Separate room temperature sensor as supplement to the Vitotrol 200A and 300A; to be used if the Vitotrol 200A or 300A cannot be installed inside the main living room or in a suitable position where the unit can capture and adjust the temperature. Installation in the main living room on an internal wall opposite radiators.
Accessories Optional Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data (continued) Vitotrol 200A One Vitotrol 200A can be used for every heating circuit in a heating system. The Vitotrol 200A can regulate one heating circuit and up to two remote controls may be connected to the control unit. KM BUS Participant The Vitotrol 200A remote control regulates the required set room temperature in standard mode, from any room in the house.
Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data Optional Accessories (continued) Vitotrol 300A One Vitotrol 300A can be used for every heating circuit in a heating system. The Vitotrol 300A can regulate up to three heating circuits. Up to two remote controls may be connected to the control unit.
Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data Accessories for Vitocrossal 300 CU3A Fuel Conversion Label Kit (NG>LPG) (included in boiler technical literature set) The Vitocrossal 300 CU3A boiler comes factory set for operation with natural gas. All Vitocrossal 300 CU3A models can be field converted to operate with liquid propane gas (as well as back to natural gas as required). The kit includes instructions and labels for field conversion.
Accessories Vitocrossal 300 CU3A 26 to 57 Technical Data Accessories for Vitocrossal 300 CU3A Low-Loss Header (continued) Principle of Operation IMPORTANT When installing a low-loss header, the system mixed supply temperature (T3) must be calculated as follows: Vprimary < Vsecondary T1 > T3 T2 = T4 Qprimary = Qsecondary T1 167° F (75° C) Vsecondary=Vprimary+Vbypass Model No. Max. system flow rate Type 80/60 17.6 USGPM (4 m3/h) Type 120/80 35.
Standard Equipment/Management System Vitocrossal 300 CU3A 26 to 57 Technical Data Standard Equipment The Vitocrossal 300 CU3A gas-fired condensing combiboiler with Inox-Crossal heat exchanger, modulating MatriX burner for liquid propane gas and natural gas (available on all models), comes standard with: ■ boiler control unit with outdoor temperature sensor, power/pump module: - installation fittings with 30 psig pressure relief valve - Temperature and pressure gauge field installation on supply pipe.
Installation Vitocrossal 300 CU3A 26 to 57 Technical Data Hydraulic Connection System design Viessmann condensing boilers can generally be installed in any pumped hot water heating system (closed system). Minimum system pressure 14 psi. The boiler water temperature is limited to 194ºF (90ºC). To minimize distribution losses and for increased efficiency we recommend that you size the heat distribution system to a max. supply temperature of 158ºF (70ºC).
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 1 Vitocrossal 300 CU3A with a direct-connected heating circuit Legend A Vitocrossal 300 CU3A boiler with Vitotronic 200, KW6B outdoor reset control B Outdoor temperature sensor ! C Vitotrol remote (optional) D Heating circuit E Heating circuit pump 20 F DHW pump sA G DHW storage tank H DHW tank temperature sensor % I Expansion tank J DHW recirculation pump 28/20 * K Temperature and pressure relief valve L Pressure relief val
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 2 Vitocrossal 300 CU3A with...
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 3 Vitocrossal 300 CU3A with... - DHW storage tank - one direct-connected heating circuit - two heating circuit with a mixing valve * Function based on coding of address 33 Installation of different heating circuits... ■ radiator heating circuit (high-temp. circuit) ■ under floor heating circuit with 3-way mixing valve (low-temp.
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 4 Vitocrossal 300 CU3A with...
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 5 Vitocrossal 300 CU3A with... - DHW storage tank - low-loss header - multiple heating circuits with mixing valves - one heating circuit without mixing valve When designing a system as illustrated above, please contact your local Viessmann Sales Representative for assistance.
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data System Layout 6 Multiple (up to eight) Vitocrossal 300 CU3A with...
Installation Examples Vitocrossal 300 CU3A 26 to 57 Technical Data Electrical Connections DISCONNECT POWER BEFORE SERVICING BOILER. If any of the original wires as supplied with the appliance must be replaced, it must be replaced with the exact equivalent. 26 CAUTION Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing. * Only one function/connection may be assigned to each connection.
Vitocrossal 300 CU3A 26 to 57 Technical Data Electrical Connections Legend 1 2 3/1 3/2 5 11 15 20 21 28/20 35 40 40A 54 96 100 100A 111 145 147 Multi 156A 156B DE1 DE2 DE3 0-10V 157 190 Installation Examples (continued) Outdoor Temperature Sensor Supply Temperature Sensor/Low Loss Header Boiler Temperature Sensor #1 Boiler Temperature Sensor #2 DHW Temperature Sensor Ionization Electrode Flue Gas temperature Sensor Boiler Pump DHW Pump Programmable Pump Output* Gas Valve Power Supply Accessory Power Out
System Design Vitocrossal 300 CU3A 26 to 57 Technical Data System Design Considerations IN THE COMMONWEALTH OF MASSACHUSETTS... this product shall be installed by a licensed plumber or gas fitter. the flexible connector (if used) cannot exceed 36”. any level type shutoff used must be of tee handle type.
System Design Vitocrossal 300 CU3A 26 to 57 Technical Data System Design Considerations (continued) System layout ■ The max. boiler water temperature for space heating and DHW production is 194°F (90°C). To minimize distribution losses, Viessmann recommends that the heating and domestic hot water systems be based on a maximum boiler supply temperature of 194°F (90°C).
5673 647 - 03 Vitocrossal 300 CU3A 26 to 57 Technical Data
5673 647 - 03 Vitocrossal 300 CU3A 26 to 57 Technical Data 31
5673 647 - 03 Technical information subject to change without notice. Printed on environmentally friendly (recycled and recyclable) paper.
