Viessmann Vitocrossal 300 CU3A 26 Installation Instructions Manual
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Viessmann Vitocrossal 300 CU3A 26 Installation Instructions Manual

Floor mounted, gas-fired condensing boiler with matrix gas burner and lambda pro control
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Installation Instructions
for use by heating contractor
Vitocrossal 300 CU3A
Models 26, 35, 45, 57, 94, 125, 160, 199
Floor mounted, gas-fired condensing boiler with MatriX gas burner and Lambda Pro control
For operation with natural gas and liquid propane gas
Heating input
19 to 199 MBH
5.6 to 58 kW
VITOCROSSAL 300
5673 648 - 15
02/2023
H
Product may not be exactly as shown
IMPORTANT
Read and save these instructions
for future reference.
Please file in Service Binder

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Summary of Contents for Viessmann Vitocrossal 300 CU3A 26

  • Page 1 Installation Instructions for use by heating contractor Vitocrossal 300 CU3A Models 26, 35, 45, 57, 94, 125, 160, 199 Floor mounted, gas-fired condensing boiler with MatriX gas burner and Lambda Pro control For operation with natural gas and liquid propane gas Heating input 19 to 199 MBH 5.6 to 58 kW...

  • Page 2: Safety, Installation And Warranty Requirements

    Safety Vitocrossal 300 CU3A 26 to 199 Installation Safety, Installation and Warranty Requirements Please ensure that these instructions are read and understood before commencing installation. Failure to comply with the instructions listed below and details printed in this manual can cause product/property damage, severe personal injury, and/or loss of life.

  • Page 3: About These Installation Instructions

    Safety Vitocrossal 300 CU3A 26 to 199 Installation Safety, Installation and Warranty Requirements Suppliers of fiberglass wool products recommend the Fiberglass wool and ceramic fiber materials following precautions be taken when handling these materials: WARNING - Avoid breathing fiberglass dust and contact with skin and eyes.

  • Page 4: Table Of Contents

    Table of Contents Vitocrossal 300 CU3A 26 to 199 Installation Page Safety Safety, Installation and Warranty Requirements....2 Product documentation..........2 Warranty..............2 Licensed professional heating contractor....2 Contaminated air............2 Advice to owner............2 Carbon monoxide.............2 Fresh air..............2 Equipment venting...........2 About these Installation Instructions......3 General Information Important Regulatory and Installation Requirements..6...
  • Page 5 Table of Contents Vitocrossal 300 CU3A 26 to 199 Installation Page Control Connections Accessing the Control Electrical Connections Box..24 External Cable Connection.........24 Temperature Sensors Overview........26 Accessing the X3 Plug..........27 Connecting the Outdoor Temperature Sensor....27 Connecting the Low-loss Header Sensor.....28 Connecting the DHW Sensor........28 Installing the LON Communication Module....30...

  • Page 6: Important Regulatory And Installation Requirements

    General Information Vitocrossal 300 CU3A 26 to 199 Installation Important Regulatory and Installation Requirements Codes The installation of this unit shall be in accordance with The following topics must be covered: local codes or, in the absence of local codes, use CAN/ Proper system operation sequence.

  • Page 7: Field Testing Of High Limit Switches

    (continued) CSD-1 Field Testing of High Limit Switches for Vitocrossal 300 CU3A boilers – where required by law. VIESSMANN IS NOT RESPONSIBLE FOR ANY DAMAGES THAT THE FOLLOWING TEST PROCEDURE MAY RESULT IN BY OVERHEATING THE SYSTEM. The fixed high limit, when tripped, produces a fault that will require manual reset of the boiler control.

  • Page 8: Applicability

    General Information Vitocrossal 300 CU3A 26 to 199 Installation Applicability CAUTION The boiler serial number must be provided when ordering replacement parts. IMPORTANT When ordering replacement parts, provide either the 16-digit boiler serial number (on the bar code label) located underneath boiler front enclosure panel.

  • Page 9: Mechanical Room

    General Information Vitocrossal 300 CU3A 26 to 199 Installation Mechanical Room During the early stages of designing a new home, we recommend that proper consideration be given to constructing a separate mechanical room dedicated to the gas- or oil-fired heating equipment and domestic hot water storage tank(s).

  • Page 10: Before Set-Up

    Set-up Vitocrossal 300 CU3A 26 to 199 Installation Before Set-up Before placing boiler in its installation location, ensure all necessary accessories are installed. CAUTION The boiler must be installed in such a way that gas ignition system components are protected from water (spraying, splashing, etc.) during boiler operation and...

  • Page 11: Connections

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections Note: The Vitocrossal is only suitable for fully pumped hot water heating systems. Never install 4-way mixing valves, overflow valves or other flow/return bypass devices. Never connect a heating return to the safety return.

  • Page 12: Dimensions

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Dimensions 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...

  • Page 13: Installation Fittings

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Installation fittings Safety header A Pressure relief valve ¾ in., 30 psig B Nipple ¾ in. x 1b in. C Street elbow ¾ in. D Air vent E Bushing ¾ in. to e in.

  • Page 14: Siting And Levelling The Boiler

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Siting and levelling the boiler Gas shut-off valve connection 1. Make gas connections in accordance with codes IMPORTANT CAN/CSA B149.1 and .2 or National Fuel Gas Code ANSI Z223.1/NFPA 54, as well as local codes.

  • Page 15: Gas Connection And Piping

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) See Vitocrossal 300, CU3A Service Instructions for applicable system coding changes. WARNING The gas supply piping must be leak tested before placing the boiler in operation. CAUTION Ensure that gas piping is large enough for all appliances in the residence.

  • Page 16: Installing Boiler Safety Devices

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Installing boiler safety devices 1. Apply sufficient amount of pipe sealant to both ends of all pipe fittings B,D,F and G and install onto coupling A and tees C.

  • Page 17: Heating Water Connections

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Typical connection Heating water connections with supplied; 1. Thoroughly flush heating system (particularly before - reducing tee 1a in. connecting the boiler to an existing system). x 1a in. x b in.

  • Page 18: Pressure Drop (Heating Water Side)

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Pressure drop (heating water side) Flow rate Legend A Boiler models CU3A 26, 35, 94, 125 B Boiler models CU3A 45, 57, 160, 199 The Vitocrossal 300 is only suitable for fully pumped hot water heating systems.

  • Page 19: Installing Drain Valve

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Installing drain valve CAUTION To prevent equipment damage, install all pipework free of load and torque stresses. Install drain valve assembly as shown in the diagram. IMPORTANT Apply sufficient amount of thread sealant when making the connections.

  • Page 20: Filling The Heating System

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Filling the Heating System CAUTION Unsuitable fill water increases the level of deposits and corrosion, and may lead to damage to the equipment. H Thoroughly flush the entire heating system prior to filling with water.

  • Page 21: Combustion Air Connection

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Combustion Air Connection CAUTION To prevent equipment damage, install all pipework free of load and torque stresses. We recommend fitting an on-site support immediately downstream of the boiler flue connection. Connect the flue outlet to the flue pipe via the shortest possible run, with a slight rise (min.

  • Page 22: Condensate Siphon

    Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Condensate Siphon 1. Remove the condensate siphon from the boiler. 2. Fill the siphon with water and reinstall onto the boiler. Legend A Retaining nut B Gasket C Siphon Condensate Connection The Vitocrossal 300 CU3A boiler comes with a built-in condensate trap.
  • Page 23 Boiler Connections Vitocrossal 300 CU3A 26 to 199 Installation Condensate Connection (continued) 1. Install the condensate drain pipe with a suitable gradient. 2. Discharge condensate from the boiler into the drain system, either directly or (if required) via a neutralization unit (accessory).

  • Page 24: Control Connections

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Accessing the Control Electrical Connections Box 1. Remove the screws from the top panel and set aside. 2. Slide the top panel to the rear of the boiler and lift up.
  • Page 25 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation External Cables Connection (continued) Applying strain relief On-site cables 1. Cut the tip from the rubber cable restraint. 2. Feed the cable through the rubber cable restraint. 3. Install the cable restraint with cable into the connection housing.

  • Page 26: Temperature Sensors Overview

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Temperature Sensors Overview Control base - External sensor connections Note: See wiring diagram on page 57 for connection to the external accessory connection box. Route cables through the openings provided at the top...

  • Page 27: Accessing The X3 Plug

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Accessing the X3 Plug 1. Remove the X3 plug from the control board. Attach sensors and reinsert the X3 plug. Refer to the following sensor information. 2. Reinstall the control cover.

  • Page 28: Connecting The Low-Loss Header Sensor

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connecting the Low-loss Header Sensor 1. Connect the low-loss header sensor (if used) to terminals X3.4/X3.5 on the boiler control board. 2. Route the sensor to the low loss header and install into the sensor well.
  • Page 29 Viessmann DHW storage tank when mounting and securing DHW tank temperature sensor %. WARNING If a DHW storage tank other than a Viessmann Vitocell 100 or 300 tank is used, the installer must verify proper operation of the Viessmann DHW tank temperature sensor with original manufacturer of the tank.

  • Page 30: Installing The Lon Communication Module

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Installing the LON Communication Module Boiler LON communication module The boiler comes with a LON communication module pre-installed. Connecting the LON module cable Refer to the Vitocrossal 300 CU3A Service Instructions for details on LON connections.

  • Page 31: Connections

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections Legend External accessory connection overview A Integrate EA1 module Note: See wiring diagram on page 57 for connection B Power/Pump connection interface to the control base. IMPORTANT Electrical installations must comply with the latest edition of: In the U.S.A., the National Electrical Code (NEC),...

  • Page 32: Routing Power/Pump Accessory Cables

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Routing power/pump accessory cables Route cables from the accessory connection modules underneath through the boiler frame and out the openings in the back of the jacketing. Note: Connecting cables will be damaged if they touch hot components.
  • Page 33 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Connecting to extension module EA1 Extension Module EA1 1. Connect the external 0-10V signal to plug 0-10V located in the extension module EA1. 2. Ensure correct polarity. 3. See chart for maximum possible boiler water temperature and required signal.

  • Page 34: Vac Thermostat Connection

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Connecting a 24 VAC Thermostat 1. Connect normally open dry contact of the switching relay (‘T-T’ contact) to terminal DE1, DE2 or DE3 of the EA1 module located in the boiler electrical junction box.
  • Page 35 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Legend A Room thermostat (dry contact) zone circuit 1 B Room thermostat (dry contact) zone circuit 2 C Room thermostat (dry contact) zone circuit 3 D EA1 module (integrated into the boiler)
  • Page 36 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Connection to boiler Pump output assignment is done using the start-up wizard. A maximum of 2 zone circuit pumps can be connected to the boiler additional pumps will require the use of an AM1 extension module.

  • Page 37: Pump Connection

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Function The aBJ output is a programmable function output and may be coded for only one of the following functions; - alarm output - DHW recirculation pump - field pump...

  • Page 38: Multi Connection

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Multi connection Normally closed safety connection A. Remove jumper (not shown) to install a field supplied normally closed relay. IMPORTANT The relay must be rated for 120VAC 5 FLA...

  • Page 39: Boiler Power Supply Connection

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Pump connection Note: See wiring diagram on page 57 for connection to the control base. Note: Maximum pump draws 2 FLA each. All 120VAC outputs must not exceed 6 FLA.
  • Page 40 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Pump modulation connection (0-10VDC) Relevant Coding Address Pump modulation signal can only be applied to output 20 A3 Heating circuit pump logic based on outdoor temp. when used as heating circuit pump A1.
  • Page 41 Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Connections (continued) Boiler power supply connection Note: See wiring diagram on page 57 for connection to the control base. Power/pump connection interface IMPORTANT Electrical installations must comply with the latest edition of: In the U.S.A., the National Electrical Code (NEC),...

  • Page 42: Fitting The Top Panels

    Control Connections Vitocrossal 300 CU3A 26 to 199 Installation Fitting the Top Panels 1. Place the control cover on the control connection housing and slide into place. 2. Install previously removed nuts onto the threaded studs. 3. Place the top jacket panel on the top of the boiler and slide in place.

  • Page 43: Installation Examples

    They further do not display all system varieties, safety devices, or concepts possible. Specific If a DHW storage tank other than a Viessmann Vitocell system layouts may be further discussed with the local 100 or 300 tank is used, the installer must verify proper Viessmann sales representative office.

  • Page 44: System Layout 1

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation System Layout 1 Vitocrossal 300 CU3A with a direct-connected heating circuit Legend A Vitocrossal 300 CU3A boiler with Installation of ... Vitotronic 200, KW6B outdoor reset control ■ radiator heating circuit (high-temp. circuit) B Outdoor temperature sensor ! ■...

  • Page 45: System Layout 2

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation System Layout 2 Vitocrossal 300 CU3A with... - DHW storage tank - one heating circuit with mixing valve and system separation Installation of ... Legend Vitocrossal 300 CU3A boiler with Vitotronic 200, ■...

  • Page 46: System Layout 3

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation System Layout 3 Vitocrossal 300 CU3A with... - DHW storage tank - one direct-connected heating circuit - two heating circuit with a mixing valve Legend Installation of different heating circuits... Vitocrossal 300 CU3A boiler with Vitotronic 200, ■...

  • Page 47: System Layout 4

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation System Layout 4 Vitocrossal 300 CU3A with... - direct-connected heating circuit - one heating circuit with system separation Legend Vitocrossal 300 CU3A boiler with Vitotronic 200, Installation of different heating circuits...

  • Page 48: System Layout 5

    - 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. Legend Vitocrossal 300 CU3A boiler with Vitotronic *1 Contact your local Sales Representative for details.

  • Page 49: System Layout 6

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation System Layout 6 Vitocrossal 300 CU3A with... - DHW storage tank - three zone circuits Legend Installation of different heating circuits... Vitocrossal 300 CU3A boilers ■ DHW production DHW storage tank ■...

  • Page 50: System Layout 7

    Proper installation and functionality in the field is the responsibility of the heating contractor. WARNING If a DHW storage tank other than a Viessmann Vitocell 100 or 300 tank is used, the installer must verify proper operation of the Viessmann DHW tank temperature sensor with the original manufacturer of the tank.

  • Page 51: System Layout 8

    Proper installation and functionality in the field is the responsibility of the heating contractor. WARNING If a DHW storage tank other than a Viessmann Vitocell 100 or 300 tank is used, the installer must verify proper operation of the Viessmann DHW tank temperature sensor with the original manufacturer of the tank.

  • Page 52: Boiler In Heating And Cooling

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation Boiler in Heating/Cooling Boiler in heating/cooling application Legend A Heating/Cooling unit The boiler, when used in connection with a refrigeration B Spring-loaded flow check valve system, must be installed ensuring the chilled medium...

  • Page 53: Boiler With Low Water Cut-Off

    Installation Examples Vitocrossal 300 CU3A 26 to 199 Installation Boiler with Low Water Cut-off Boiler with low water cut-off (remote-mounted, field supplied) A low water cut-off may be required by local codes. Do not install an isolation valve between boiler and low water cut-off.

  • Page 54: Technical Data

    Additional Information Vitocrossal 300 CU3A 26 to 199 Installation Technical Data CU3A Boiler Model No. 26, 94 35, 125 45, 160 57, 199 Natural Gas / Liquid Propane Gas CSA input 19-94 25-125 43-160 43-199 (kW) (5.6-27.5) (7.3-36.6) (12.6-47) (12.6-58) 17.7-87...
  • Page 55 For details refer to the Installation Instructions for the Vitocrossal 300 CU3A Venting System. Standby losses measured from the boiler temperature sensor well based on a boiler water temperature of 158°F (70°C) and a room temperature of 68°F (20°C). For information regarding other Viessmann System Technology componentry, please reference documentation of respective product.

  • Page 56: Electrical Connections

    Additional Information Vitocrossal 300 CU3A 26 to 199 Installation Electrical Connections Power supply connection of accessories Cabling required for: The power supply connection of accessories can be made H outdoor temperature sensor directly at the control. The connection is activated and H Vitotronic 200-H, HK1B mixing valve control deactivated with the system on/off switch.
  • Page 57 Additional Information Vitocrossal 300 CU3A 26 to 199 Installation Electrical Connections (continued) CAUTION WARNING DISCONNECT POWER BEFORE Label all wires prior to disconnection SERVICING BOILER. when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation If any of the original wires as after servicing.
  • Page 58 Additional Information Vitocrossal 300 CU3A 26 to 199 Installation Electrical Connections (continued) Legend IMPORTANT Outdoor Temperature Sensor Supply Temperature Sensor/Low Loss Header Electrical installations must comply with the latest edition of: Boiler Temperature Sensor #1 Boiler Temperature Sensor #2 In the U.S.A., the National Electrical Code (NEC),...

  • Page 59: Lighting And Operating Instructions

    Additional Information Vitocrossal 300 CU3A 26 to 199 Installation Lighting and Operating Instructions FOR YOUR SAFETY READ BEFORE OPERATING W A R N I N G: If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life.
  • Page 60 Vitocrossal 300 CU3A 26 to 199 Installation...

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