Viessmann Vitocrossal 300 Service Manual
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Viessmann Vitocrossal 300 Service Manual

Floor mounted, gas-fired condensing boiler with matrix gas burner and lambda pro control
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See also: Instruction and Installation Manual , Technical Data Manual
Service Instructions
for use by heating contractor
Vitocrossal 300
CU3A Series 26 to 57
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 649 - 03 06/2015
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

  • Page 1 Service Instructions for use by heating contractor Vitocrossal 300 CU3A Series 26 to 57 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

    Safety Vitocrossal 300 CU3A 26 to 57 Service 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: Fiberglass Wool And Ceramic Fiber Materials

    Safety Vitocrossal 300 CU3A 26 to 57 Service Safety, Installation and Warranty Requirements (continued) 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 57 Service Page Safety, Installation and Warranty Requirements....2 Safety Product documentation..........2 Warranty..............2 Licensed professional heating contractor....2 Contaminated air...........2 Advice to owner............2 Operating and Service Documentation......2 Carbon monoxide...........2 Fresh air..............2 Equipment venting..........2 Fiberglass wool and ceramic fiber materials....3 First aid measures..........3...
  • Page 5 Table of Contents Vitocrossal 300 CU3A 26 to 57 Service Page Service (continued) Cleaning and Reconnecting the Condensate Drain System.22 Checking Gaskets and Thermal Insulation Components on the Boiler.............23 Checking the Diaphragm Expansion Vessel and System Pressure............23 Fitting the Burner............24 Clock Natural Gas Meter..........24...

  • Page 6: General Information

    General Information Vitocrossal 300 CU3A 26 to 57 Service Necessary Tools Testing/analysis equipment (Use only calibrated equipment) Cleaning supplies H Multimeter to measure 0 - 230V, 0 - 12A AC and H Plastic hand brush 0-100 mA DC H Rags...
  • Page 7 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

    (DHW) production. The Vitocrossal 300 CU3A series boiler comes factory set for operation with natural gas. For a fuel conversion to liquid propane gas no conversion kit is required.

  • Page 9: Mechanical Room

    General Information Vitocrossal 300 CU3A 26 to 57 Service 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: Startup

    Startup Vitocrossal 300 CU3A 26 to 57 Service 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 11: Removing The Front Panels

    Startup Vitocrossal 300 CU3A 26 to 57 Service Removing the Front Panel 1. Remove the retaining screw and set aside. 2. Pull the top of the boiler cover away from the boiler, lift off and set aside. Filling Siphon with Water 1.

  • Page 12: Opening The Control Unit

    Startup Vitocrossal 300 CU3A 26 to 57 Service Opening the Control Unit Vitotronic 200, type KW6B 1. Lift the programming unit A into the upright position (the angle of the programming unit can be adjusted using the pushbutton on the side B).

  • Page 13: Check Power Supply Connection

    Check Power Supply Connection An external accessories connection modules are IMPORTANT integrated into the Vitocrossal 300 CU3A boiler, which requires a 120VAC power supply from a wall receptacle In Canada all electrical wiring is to be done in accordance (15A fuse protected).

  • Page 14: Select Gas Type

    Startup Vitocrossal 300 CU3A 26 to 57 Service Select Gas Type Note: the Vitocrossal 300 CU3A boiler is factory set to operate with natural gas . See following subsection for conversion instructions to liquid propane gas. 1. Ensure that the fuel type listed on the boiler rating plate is the correct type for the installation being attempted.

  • Page 15: Measuring The Static Pressure And Running Pressure

    Startup Vitocrossal 300 CU3A 26 to 57 Service Measure Static Pressure and Running Pressure 1. To measure static and/or running pressure remove boiler enclosure panel as indicated page 11 in these instructions. 2. Close gas shutoff valve (field supplied). 3. Loosen screw at inlet gas pressure port A on the gas combination valve, do not remove completely.

  • Page 16: Set Maximum Output

    Startup Vitocrossal 300 CU3A 26 to 57 Service Setting the Maximum Output You can limit the maximum output for heating operation. The limit is set via the modulation range. The max. adjustable output is limited upwards by the boiler coding card.

  • Page 17: Perform Combustion Analysis

    Startup Vitocrossal 300 CU3A 26 to 57 Service Perform Combustion Analysis IMPORTANT A CO measurement (see page 25) must be taken before and after working on gas appliances to eliminate risks to health and to guarantee the satisfactory condition of the system.

  • Page 18: Sequence Of Operation And Potential Faults During Each Startup Cycle

    Startup Vitocrossal 300 CU3A 26 to 57 Service Sequence of Operation and Potential Faults During Each Startup Cycle Function sequence and possible faults For further details on faults, see page 78.

  • Page 19: Service

    Service Vitocrossal 300 CU3A 26 to 57 Service Removing the Burner and Checking the Burner Gasket 1. Switch OFF the main power supply and the ON/OFF switch at the control unit. 2. Close the gas shut-off valve and safeguard against reopening.

  • Page 20: Checking Burner Mesh Assembly And Refractory

    Service Vitocrossal 300 CU3A 26 to 57 Service Checking Burner Mesh Assembly and Refractory Replace the burner mesh assembly if the wire mesh is damaged. 1. Remove electrodes A. 2. Undo four nuts D and remove fan with gas valve C.

  • Page 21: Cleaning The Combustion Chamber And Heating Surfaces

    Service Vitocrossal 300 CU3A 26 to 57 Service Cleaning the Combustion Chamber and Heating Surfaces Remove front enclosure panel (if still installed) as IMPORTANT per the instructions on page 11 in this manual, and reinstall panel upon completion of service work.

  • Page 22: Cleaning And Reconnecting The Condensate Drain System

    Service Vitocrossal 300 CU3A 26 to 57 Service Cleaning and Reconnecting the Condensate Drain System Flue collector, condensate drain, siphon, neutralizing system and all hoses or pipe runs in between are considered part of the condensate drain system. Note: Clean the inside of the condensate drain system at least annually.

  • Page 23: Checking Gaskets And Thermal Insulation Components On The Boiler

    Service Vitocrossal 300 CU3A 26 to 57 Service Checking Gaskets and Thermal Insulation Components on the Boiler 1. Check the gasket/seal on the flue gas collector A between the flue gas collector C and the boiler body B for tightness.

  • Page 24: Fitting The Burner

    Clock Natural Gas Meter Clock natural gas meter to verify input. For example: A Vitocrossal 300 CU3A-57 boiler (199000 Btu/h max. Ensure all other gas equipment served by the meter input) requires 181 sec. to use 10 ft. of natural gas.

  • Page 25: Check Co 2 Setting

    Service Vitocrossal 300 CU3A 26 to 57 Service Check CO Setting The Vitocrossal 300 CU3A boiler is equipped with 1. Connect a flue gas analyzer to test port A at boiler the Combustion Management System developed by vent pipe adaptor.

  • Page 26: Combustion Management System

    1.37 1.40 1.44 1.48 The Vitocrossal 300 CU3A boilers come equipped with Lambda Pro, the industry’s first intelligent combustion management system. Check Functioning of Safety Valves Ensure proper operation of low water cut-off(s) (if applicable), pressure relief valve, and pump(s).

  • Page 27: Check Electrical Connections

    Service Vitocrossal 300 CU3A 26 to 57 Service Check Electrical Connections Ensure all plug-in connectors and strain reliefs make positive contact and are seated properly. Refer to the Installation Instructions Check Gas Pipes and Fittings for Leaks Note: For the tightness test, use only suitable and approved leak detecting agents and devices.

  • Page 28: Example Layout 1

    Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 1 DHW heating by the solar thermal system Matching the control unit to the heating system Solar circuit pump wE starts and DHW tank qR is heated Subject to the equipment level, the control unit must up, if the temperature differential between collector be matched to the system.
  • Page 29 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 1 (continued) Hydraulic installation scheme ID: 4605300_1006_01 Note: This scheme is a basic example without shut-off valves or safety equipment. This does not replace the need for local engineering.
  • Page 30 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 1 (continued) Equipment required ID: 4605300_1006_01 Pos. Designation Boiler with Control unit Vitocrossal 300 with Vitotronic 200, type KW6B Outdoor temperature sensor ATS DHW heating by the boiler DHW tank...
  • Page 31 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 1 (continued) Electrical installation diagram...

  • Page 32: Example Layout 2

    Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 2 System version 2 DHW heating by the solar thermal system One heating circuit without mixing valve, one heating Solar circuit pump wE starts and DHW tank qR is heated...
  • Page 33 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 2 (continued) Hydraulic installation scheme ID: 4605301_1006_02 Note: This scheme is a basic example without shut-off valves or safety equipment. This does not replace the need for local engineering.
  • Page 34 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 2 (continued) Equipment required ID: 4605301_1006_02 Pos. Designation Boiler with Control unit Vitocrossal 300 with Vitotronic 200, type KW6B Outdoor temperature sensor ATS DHW heating by the boiler DHW tank...
  • Page 35 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 2 (continued) Equipment required ID: 4605301_1006_02 Pos. Designation Accessories Internal extension H1: (integrated) Connection, external safety solenoid valve (LPG)  Central fault message (alternative to extension EA1)  Extension EA1 (integrated)
  • Page 36 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 2 (continued) Electrical installation diagram...

  • Page 37: Example Layout 3

    Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 3 System version 3 DHW heating by the solar thermal system One heating circuit without mixing valve and two heating Solar circuit pump wE starts and DHW tank qR is heated...
  • Page 38 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 3 (continued) Hydraulic installation scheme ID: 4605302_1006_01 Note: This scheme is a basic example without shut-off valves or safety equipment. This does not replace the need for local engineering.
  • Page 39 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 3 (continued) Equipment required ID: 4605302_1006_01 Pos. Designation Boiler with Control unit Vitocrossal 300 with Vitotronic 200, type KW6A Outside temperature sensor ATS DHW heating by the boiler DHW tank...
  • Page 40 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 3 (continued) Equipment required ID: 4605301_1006_02 Pos. Designation Accessories Internal extension H1: (integrated) Connection, external safety solenoid valve (LPG)  Central fault message (alternative to extension EA1)  Extension EA1 (integrated)
  • Page 41 Service Vitocrossal 300 CU3A 26 to 57 Service Example Layout 3 (continued) Electrical installation diagram...

  • Page 42: Start-Up

    Service Vitocrossal 300 CU3A 26 to 57 Service Start-up Starting the heating system 1. Check the heating system pressure at the pressure gauge. The heating system pressure is too low if the indicator is below 14 psi. In this case, top up with water or notify your local heating contractor.
  • Page 43 Service Vitocrossal 300 CU3A 26 to 57 Service Menu (continued) Note: For any other connected heating circuits, use the settings in the extended menu. Call up the standard menu as follows: - If the screen saver is active - Press any key except...

  • Page 44: Functional Description

    Service Vitocrossal 300 CU3A 26 to 57 Service Functional Description Space heating mode The control unit calculates a boiler water setpoint temperature based on the outdoor or room temperature (where a room temperature dependent remote control is connected) and on the slope/shift of the heating curve.

  • Page 45: Adjusting The Heating Curves

    Service Vitocrossal 300 CU3A 26 to 57 Service Adjusting the Heating Curves Changing the slope and shift The heating curves illustrate the relationship between the outdoor temperature and the boiler water or supply temperature. To put it simply, the lower the outside temperature, the higher the boiler water or supply temperature.
  • Page 46 Service Vitocrossal 300 CU3A 26 to 57 Service Adjusting the Heating Curves (continued) Reduced room temperature Adjusting the set room temperature Standard room temperature Example 1: Adjustment of the standard room temperature Example 2: Adjustment of reduced room temperature from 68°F to 79°F (20°C to 26°C) from 41°F to 57°F (5°C to 14°C)
  • Page 47 Service Vitocrossal 300 CU3A 26 to 57 Service Adjusting the Heating Curves (continued) Raising the reduced room temperature During operation with reduced room temperature, the reduced set room temperature can be automatically raised subject to the outside temperature. The temperature is raised in accordance with the selected heating curve, but no higher than the set standard room temperature.
  • Page 48 Service Vitocrossal 300 CU3A 26 to 57 Service Adjusting the Heating Curves (continued) Allocating heating circuits to the remote control The heating circuit allocation must be configured when commissioning the Vitotrol 200A or Vitotrol 300A. Heating circuit Configuration Vitotrol Vitotrol...
  • Page 49 Service Vitocrossal 300 CU3A 26 to 57 Service Connecting the Boiler to a LON System (continued) Boiler control unit Vitotronic 200-H Vitotronic 200-H Vitocom (e.g. HK1B *1 mixing valve (e.g. HK1B *1 multiple *1 LON communication control) mixing valve control) module Participant no.

  • Page 50: General

    Coding 1 Vitocrossal 300 CU3A 26 to 57 Service General Accessing coding level 1 1. Press OK and simultaneously for approximately 4 seconds. Note: Codes are displayed as plain text. 2. “Coding level 1” Codes that have no function due to the heating 3.

  • Page 51: Boiler

    Coding 1 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory set mode Possible change Participant no. Internal circulation pump function 51:0 System with low loss header: 51:1 System with low loss header: Internal circulation pump always...

  • Page 52: Dhw

    Coding 1 Vitocrossal 300 CU3A 26 to 57 Service Coding in the factory setting Possible change Enable DHW recirculation pump 67:40 For solar DHW heating: 67:0 Set DHW temperature adjustable from Set DHW temperature 32 to 203°F (0 to 95°C) (limited by 104°F (40°C).
  • Page 53 Coding 1 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 Select “Heating circuit ...” Coding in the factory setting Possible change Priority DHW heating A2:2 DHW tank priority applicable to A2:0 Without DHW tank priority...

  • Page 54: Heating Circuit 1, 2 And 3

    Coding 1 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change Extended economy function mixing valve A7:0 Without mixing valve economy A7:1 With mixing valve economy function function (only with circuits with...
  • Page 55 Coding 1 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change Minimum supply temperature heating circuit C5:20 Electronic minimum supply C5:1 Minimum limit adjustable from temp. limit 68°F (20°C) 34 to 260°F (1 to 127°C)
  • Page 56 Coding 1 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change Start temperature raising F8:-5 Temperature limit for F8:+10 Temperature limit adjustable from terminating the reduced mode +50 to -76°F (+10 to -60°C).

  • Page 57: General

    Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General If the heating circuits were given individual designations, Calling up coding level 2 the selected designation and “HC1”, “HC2” or “HC3” Note: At coding level 2, all codes are accessible, including appear instead: the codes at coding level 1.
  • Page 58 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory setting Possible change No access to the coding 11:9 Access open to the coding 11:≠ 9 addresses for the combustion addresses for the combustion controller parameters controller parameters.
  • Page 59 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory setting Possible change 3B:0 Function input DE2 at extension 3B:1 Function input DE2: Heating EA1: Not assigned program - changeover. 3B:2 Function input DE2: External demand with set supply temperature.
  • Page 60 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory setting Possible change 4B:0 4B:1 External demand. Function input lH: Room 4B:2 External blocking. thermostat (Vitotrol 100) for constant temperature control 51:0 System with low loss header:...
  • Page 61 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory setting Possible change 79:1 With LON communication 79:0 Control unit is not fault manager. module: Control unit is fault manager 7B:1 With LON communication 7B:0 Does not transmit time.
  • Page 62 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service General (continued) Coding in the factory setting Possible change 94:0 Without Open Therm extension 94:1 With Open Therm extension (automatic recognition). 95:0 Without Vitocom 100 95:1 With Vitocom 100 communication communication interface interface (automatic recognition).

  • Page 63: Boiler

    Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Boiler Coding in the factory setting Possible change 06:95 Maximum limit of the boiler 06:20 Maximum limit of the boiler water water temperature, specified temperature within the ranges in °C by the boiler coding card 06:127 specified by the boiler.

  • Page 64: Dhw

    Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Coding in the factory setting Possible change 56:0 Set DHW temperature 56:1 Set DHW temperature adjustable adjustable from 50 to 140°F from 50 to over 140°F (10 to (10 to 60°C) over 60°C).
  • Page 65 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service (continued) Coding in the factory setting Possible change 65:0 65:0 DO NOT ADJUST 65:3 67:40 For solar DHW heating: 67:0 Set DHW temperature Set DHW temperature adjustable from 32 to 203°F 104°F (40°C).

  • Page 66: Solar

    Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Solar Note: The solar group is only displayed if a solar control module, type SM1, is connected. Coding in the factory setting Possible change 00:8 The solar circuit pump starts 00:2...
  • Page 67 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Solar (continued) Coding in the factory setting Possible change 09:130 The solar circuit pump stops 09:20 Temperature adjustable from if the collector temperature 68 to 392°F (20 to 200°C). reaches 266°F (130°C)
  • Page 68 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Solar (continued) Coding in the factory setting Possible change 11:50 Set DHW tank temperature for 11:10 The set DHW tank temperature for solar 122°F (50°C). solar can be adjusted from 50 to...
  • Page 69 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Solar (continued) Coding in the factory setting Possible change 23:4 Stop temperature differential 23:2 Stop temperature differential for central heating for central heating backup is backup: 4 K. 23:30 adjustable from 1 to 29 K.

  • Page 70: Heating Circuit 1, 2 And 3

    Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 Coding in the factory setting Possible change A0:0 Without remote control A0:1 With Vitotrol 200A (automatic recognition). A0:2 With Vitotrol 300A (automatic recognition). A1:0 All possible settings at the...
  • Page 71 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change A4:0 With frost protection A4:1 No frost protection; this setting is only possible if code “A3:-9” has been selected.
  • Page 72 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change A9:0 With pump idle time: A9:0 Without pump idle time. Heating circuit pump “OFF” if A9:1 With pump idle time, adjustable the set value is altered through from 1 to 15.
  • Page 73 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change C5:20 Electronic minimum supply C5:1 Minimum limit adjustable from 1 to temperature limit 68°F 260°F (127°C) (limited by boiler- (20°C)
  • Page 74 Coding 2 Vitocrossal 300 CU3A 26 to 57 Service Heating Circuit 1, 2 and 3 (continued) Coding in the factory setting Possible change E5:0 Without external variable speed E5:1 With external variable speed heating heating circuit pump circuit pump. E6:...

  • Page 75: Calling Up The Service Level

    Diagnosis and Service Scans Vitocrossal 300 CU3A 26 to 57 Service Calling up the Service Level Press OK and simultaneously for approximately 4 sec. Service menu overview Scanning and resetting the “Service” display After the limits specified in coding addresses “21” and “23”...

  • Page 76: Diagnosis

    Diagnosis and Service Scans Vitocrossal 300 CU3A 26 to 57 Service Diagnosis Brief scan Scanning operating data In the brief scan, you can call up temperatures, software - Operating data can be scanned in six areas. versions and connected components, for example: See “Diagnosis”...

  • Page 77: Checking Outputs (Relay Tests)

    Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Checking Outputs (relay tests) 1. Press OK and simultaneously for approximately 4 sec. 2. “Actuator test” The following relay outputs can be controlled subject to system design: Display Explanation Base load Start Burner operated at minimum output;...

  • Page 78: Fault Codes

    Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes  In the event of a fault, red fault indicator A flashes. “ “ flashes on the display and “Fault” is shown. The fault code is displayed with OK. For an explanation of the fault code, see the following pages.
  • Page 79 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Boiler operates based on outdoor Short circuit on outdoor Check the outdoor temperature temperature of 32°F (0°C) temperature sensor sensor (see page 86).
  • Page 80 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action No solar DHW heating Collector temperature Check the sensor & at the sensor & cable solar control module. broken Control mode...
  • Page 81 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Control mode without remote Communication error, Check connections, cable, control remote control Vitotrol coding address “A0” in “Heating heating circuit 2 circuit”...
  • Page 82 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Control mode Input DE3 reports a Remove fault at appliance fault at extension EA1 concerned. Control mode without Short circuit on room...
  • Page 83 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Burner blocked Fault, supply voltage Replace the control unit. 24 V Burner blocked Fault flame amplifier Replace control unit. Burner in a fault mode...
  • Page 84 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Burner in a fault mode At burner start, flame Check gas supply (gas pressure signal is missing or too and gas regulator). Check gas weak train.
  • Page 85 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Fault Codes (continued) Fault code on display System behavior*1 Cause Corrective action Burner in fault mode Gas valve closes too Check the gas valve. late Check both control wiring/ connections. Press reset button R.

  • Page 86: Corrective Action

    Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Corrective Action 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 87 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Corrective Action (continued) Checking the DHW / low loss header / heating circuit / room temperature sensor 1. Pull the leads from temperature sensor. 2. Check the sensor resistance and compare it with the curve.
  • Page 88 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Corrective Action (continued) Checking the flue gas temperature sensor The flue gas temperature sensor locks out the boiler when the permissible flue gas temperature is exceeded. Reset the interlock after the flue system has cooled down by pressing reset button R.
  • Page 89 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Corrective Action (continued) Legend A Integrate EA1 module B Power/pump connection interface C Fuse F1 (Integrate EA1 module) D Fuse F2 (Power/pump connection interface) E Fuse F1 (Power/pump connection interface) Checking the electrical connect module fuse 1.
  • Page 90 Troubleshooting Vitocrossal 300 CU3A 26 to 57 Service Corrective Action (continued) Extension kit for heating circuit with mixing valve Checking the setting of rotary selector S1 The rotary selector on the PCB of the extension kit defines the assignment to the relevant heating circuit.

  • Page 91: Internal Extensions Ea1

    Function Description Vitocrossal 300 CU3A 26 to 57 Service Internal Extensions EA1 Legend Digital input 1 Digital input 2 Digital input 3 0 – 10V 0 - 10V input Power supply fÖ A Power supply for additional accessories Central fault message/...
  • Page 92 Function Description Vitocrossal 300 CU3A 26 to 57 Service Internal Extensions EA1 (continued) Digital data inputs DE1 to DE3 Effect of the external blocking function on the pumps The following functions can be connected alternatively: The effect on the respective heating circuit pump is selected in coding address D6 in the “Heating circuit”...

  • Page 93: Control Functions

    Function Description Vitocrossal 300 CU3A 26 to 57 Service Control Functions External heating program changeover External blocking The “External blocking” and “External blocking and fault The “External heating program changeover” function is message input” functions are connected via extension connected via extension EA1. There are 3 inputs available EA1.

  • Page 94: Wiring Diagram

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Wiring Diagram 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 95 Additional Information Vitocrossal 300 CU3A 26 to 57 Service Wiring Diagram (continued) Legend 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...

  • Page 96: Fitting The Front Panel

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Fitting the Front Panel 1. Place the front cover onto the locating pegs. 2. Push the top of the panel in place. 3. Secure in place with the retaining screw.

  • Page 97: Burner Program Sequence Of Operation

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Burner Program Sequence of Operation Phase 0: Stand-by Phase 6: Burner modulation operation or calibration Complete shutdown until the next call for heat. In this At the end of the flame stabilization period (4.5 seconds.),...

  • Page 98: Parts Lists

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Parts Lists Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Ordering Parts: Please provide Model and Serial Number A when ordering replacement parts. Order replacement components from your Viessmann distributor.
  • Page 99 Additional Information Vitocrossal 300 CU3A 26 to 57 Service Parts Lists (continued) Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Parts for Main Enclosure Assembly 0001 Spring clip for insulation (set of 4)
  • Page 100 Additional Information Vitocrossal 300 CU3A 26 to 57 Service Parts Lists (continued) Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Parts for Control Assembly 0001 Control console 0002 Hinge for control housing (each) 0003 Coding plug 0004 Fuse, T6.3A/250V (set of 10)
  • Page 101 Additional Information Vitocrossal 300 CU3A 26 to 57 Service Parts Lists (continued) Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Parts for Boiler Assembly 0001 Sensor well, G½ L=150 with clip...
  • Page 102 Additional Information Vitocrossal 300 CU3A 26 to 57 Service Parts Lists (continued) Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Parts for Burner Assembly 0001 Burner gasket 0014 Accessory pack for burner parts...

  • Page 103: Installation Fittings

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Installation Fittings Model No. Serial No. CU3A 26 Boiler 7553000jjjjjjjjj CU3A 35 Boiler 7553001jjjjjjjjj CU3A 45 Boiler 7553002jjjjjjjjj CU3A 57 Boiler 7553003jjjjjjjjj Ordering Parts: Please provide Model and Serial Number A when ordering replacement parts.

  • Page 104: Technical Data

    If the gas supply pressure exceeds the maximum gas supply pressure value, a separate gas pressure regulator must be installed upstream of the heating system. Note: For high altitude installation at 10,000 ft. the input for model Vitocrossal 300 CU3A will have an altitude de-ration of 18%.
  • Page 105 Based on maximum input rate. For side wall vent installations (coaxial system): Do not exceed max. equivalent length specified in the Installation Instructions of the Vitocrossal 300 CU3A Venting System. Do not attempt to common-vent Vitocrossal 300 CU3A with any other appliance.

  • Page 106: Maintenance Record

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service Maintenance Record...

  • Page 107: Lighting And Operating Instructions

    Additional Information Vitocrossal 300 CU3A 26 to 57 Service 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 108 Vitocrossal 300 CU3A 26 to 57 Service...

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