Viessmann VITODENS 200 User manual

Please file in Service Binder
for use by heating contractor
5285 538 - 01 07/2020
Start-up/Service Instructions
VITODENS
r
200
Vitodens 200, WB2 Series
Wall-mounted, gas-fired condensing boiler
For natural gas and liquid propane
NG heating input 25 to 124 MBH
7 to 36 kW
LP heating input 25 to 112 MBH
7 to 33 kW
Read and save these instructions
for future reference.
Product may not be exactly as shown
IMPORTANT

Vitodens 200 WB2 Service
5285 538 - 01
Safety
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. Ensure all requirements below are understood and fulfilled (including detailed information
found in manual subsections).
WARNING
Installers must follow local regulations with respect to
installation of carbon monoxide detectors. Follow the
Viessmann maintenance schedule of the boiler contained
in this manual.
Product documentation
Read all applicable documentation before commencing
installation. Store documentation near boiler in a
readily accessible location for reference in the future
by service personnel.
For a listing of applicable literature,
please see section entitled “Important
Regulatory and Safety Requirements”.
Warranty
Information contained in this and
related product documentation must
be read and followed. Failure to do
so renders the warranty null and void.
Licensed professional heating contractor
The installation, adjustment, service and maintenance
of this equipment must be performed by a licensed
professional heating contractor.
Please see section entitled
“Important Regulatory and Installation
Requirements”.
Advice to owner
Once the installation work is complete, the heating
contractor must familiarize the system operator/
ultimate owner with all equipment, as well as safety
precautions/requirements, shutdown procedure, and
the need for professional service annually before the
heating season begins.
WARNING
This boiler requires fresh air for safe operation and must
be installed with provisions for adequate combustion
and ventilation air (in accordance with local codes and
regulations of authorities having jurisdiction).
Do not operate this boiler in areas with contaminated
combustion air. High levels of contaminants such as
dust, lint or chemicals can be found at construction
sites, home renovations, in garages, workshops, in dry
cleaning/laundry facilities, near swimming pools and in
manufacturing facilities.
Contaminated combustion air will damage the boiler
and may lead to substantial property damage, severe
personal injury and/or loss of life. Ensure boiler/burner is
inspected and serviced by a qualified heating contractor
at least once a year in accordance with the Service
Instructions of the boiler.
Carbon monoxide
Improper installation, adjustment, service and/or
maintenance can cause flue products to flow into
living space. Flue products contain poisonous carbon
monoxide gas.
For information pertaining to the
proper installation, adjustment, service
and maintenance of this equipment to
avoid formation of carbon monoxide,
please see subsection entitled
“Mechanical room” and “Venting requirements” in
the “Installation Instructions”.
Operating and Service Documentation
It is recommended that all product documentation such
as parts lists, operating and service instructions be
handed over to the system user for storage.
Documentation is to be stored near boiler in a readily
accessible location for reference by service personnel.
2

Page
3
Vitodens 200 WB2 Service
5285 583 - 01
Table of Contents
Safety, Installation and Warranty Requirements..............2
Important Regulatory and Installation Requirements........4
About these Service Instructions..................................5
Necessary Tools.........................................................5
Removing and Reinstalling Front Enclosure Panel and
Cover Panel...............................................................6
Fill Heating System with Water....................................7
Check Power Supply Connection ............................... 8
Select Language...................................................... 9
Heating Contractor Address Input .............................. 9
Select Appropriate Gas Type.....................................10
Measure Static Pressure and Running Pressure .......... 10
How the Vitodens 200 Boiler Operates ..................... 12
Check CO2Setting ................................................ 13
Clock Natural Gas Meter ...........................................14
Check Orifice Size ....................................................14
Check all Primary and Secondary Circuit Connections
for Leaks.................................................................15
Perform Combustion Analysis ....................................15
Check Venting System for Leaks (circular air gap
measurement) .........................................................15
Disassemble Burner and Check Burner Gasket..............16
Visually Check the Exterior of the Burner Mesh Assembly.16
Replace Burner Mesh Assembly..................................16
Check and Adjust Ignition and Ionization Electrode .......17
Check Condensate Drain ...........................................17
Check Neutralization Unit ..........................................18
Clean Combustion Chamber/Heat Exchanger Surfaces,
and Mount Burner ....................................................18
Check Flow Rate Limiter and Water Flow Switch Filter ...19
Check Diaphragm Expansion Tank and System Pressure .19
Check Functioning of Safety Valves............................19
Check Electrical Connections .................................. 19
Check Functioning of Safety Valves ......................... 20
Check Electrical Connections ....................................20
Check Gas Pipes and Fittings for Leaks..................... 20
Measure Ionization Current .......................................21
Verify Programming Unit System Coding Addresses ... 21
Check Extension Kit for Heating Circuit with Mixing Valve .22
Check Dekamatik-HK ............................................. 23
Troubleshooting Steps ..............................................24
Diagnosis ................................................................25
Correction ...............................................................35
Technical Data.........................................................43
Burner Control Unit LGM 29.XX .................................44
Control Unit for Weather-Responsive Operation............45
Jumper Assignment and Codings ...............................68
Replacement of Circuit Board VR20 ............................69
Replacement of Burner Control Unit LGM 29................70
Wiring Diagram ........................................................72
Parts Lists ...............................................................73
Maintenance Record .................................................78
Lighting and Operation Instructions.............................79
Safety
General Information
Start-up and Service
Troubleshooting
Additional information

Vitodens 200 WB2 Service
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4
General Information
Important Regulatory and Installation Requirements
Codes
The installation of this unit shall be in accordance with
local codes or, in the absence of local codes, use CAN/
CSA-B149.1 or .2 Installation Codes for Gas Burning
Appliances for Canada. For U.S. installations use the
National Fuel Gas Code ANSI Z223.1. Always use latest
editions of codes.
In Canada all electrical wiring is to be done in accordance
with the latest edition of CSA C22.1 Part 1 and/or local
codes. In the U.S. use the National Electrical Code ANSI/
NFPA 70. The heating contractor must also comply with
both the Standard for Controls and Safety Devices for
Automatically Fired Boilers, ANSI/ASME CSD-1, and
the Installation Code for Hydronic Heating Systems,
CSA B214-01, where required by the authority having
jurisdiction.
Instructing the system user
The installer of the system is responsible to ensure the
system operator/ultimate owner is made familiar with the
system functioning, its activation, and its shut-down.
The following topics must be covered:
- Proper system operation sequence.
- Explain the equipment.
- Demonstrate an emergency shut-down, what to do
and what not.
- Explain that there is no substitute for proper
maintenance to help ensure safe operation.
Initial start-up
Initial start-up must be performed by a qualified heating
contractor. Proper completion of the Maintenance Record
by the heating contractor is also required.
The Maintenance Record is located in the Service
Instructions.
Working on the equipment
The installation, adjustment, service, and maintenance
of this boiler must be done by a licensed professional
heating contractor who is qualified and experienced in
the installation, service, and maintenance of hot water
boilers. There are no user serviceable parts on the boiler,
burners, or control.
Please carefully read this manual prior to attempting
start-up, maintenance or service. Any warranty is null
and void if these instructions are not followed.
For information regarding other Viessmann System
Technology componentry, please reference
documentation of the respective product.
We offer frequent installation and service seminars to
familiarize our partners with our products. Please inquire.
Ensure main power supply to equipment, the heating
system, and all external controls has been deactivated.
Close main gas supply valve. Take precautions in all
instances to avoid accidental activation of power during
service work.
The completeness and functionality of field supplied
electrical controls and components must be verified by
the heating contractor. These include low water
cut-offs, flow switches (if used), staging controls,
pumps, motorized valves, air vents, thermostats, etc.
Technical literature
Literature for the Vitodens boiler:
- Technical Data Manual
- Installation Instructions
- Start-up/Service Instructions
- Operating Instructions and User’s Information Manual
- Instructions of other Viessmann products utilized and
installed
- Installation codes mentioned in this manual
Leave all literature at the installation site and advise the
system operator/ultimate owner where the literature can
be found. Contact Viessmann for additional copies.
This product comes with several safety instruction labels
attached.
Do not remove!
Contact Viessmann immediately if replacement labels are
required.

Vitodens 200 WB2 Service
5
5285 538 - 01
About these Service Instructions
Take note of all symbols and notations intended to draw attention to potential hazards or important product
information. These include “WARNING”, “CAUTION”, and “IMPORTANT”. See below.

IMPORTANT
Warnings draw your attention to the presence of
potential hazards or important product information.
Cautions draw your attention to the presence of
potential hazards or important product information.
Helpful hints for installation, operation or maintenance
which pertain to the product.
This symbol indicates that additional, pertinent
information is to be found.
This symbol indicates that other instructions must
be referenced.
WARNING
Indicates an imminently hazardous situation which,
if not avoided, could result in death, serious injury
or substantial product/property damage.
CAUTION
Indicates an imminently hazardous situation which,
if not avoided, may result in minor injury or product/
property damage.
Necessary Tools
Testing/analysis equipment (Use only calibrated equipment)
HMultimeter to measure 0 - 230V, 0 - 12A AC and
0-100 mA DC
HFlue gas analyzer to measure % CO2or O2(i.e.
Bacharach fluid samplers or suitable electronic analyzer)
HManometer to measure gas pressure 0 to 11 "w.c.
(accurately) and up to 28 "w.c. gas pressure (or a non-
electric Magnehelic® manometer may also be utilized)
HStack thermometer 0 to 500°F (0 to 260°C)
HBacharach calculator or suitable tables to calculate
efficiency
HCarbon monoxide measuring equipment 0 to 400 ppm
Cleaning supplies
HPlastic hand brush
HRags
Special items
HApproved leak detection fluid for natural gas and
liquid propane gas
HPipe joint sealant
General Information

Vitodens 200 WB2 Service
5285 538 - 01
6
General Information
Removing and Reinstalling Front Enclosure Panel and Cover Panel
Some of the following start-up/service steps require the
removal of the front enclosure panel and the cover panel.
To avoid personal injury and/or product damage of any
kind please follow the instructions below carefully when
removing or reinstalling the front enclosure panel and
cover panel.
To remove front enclosure panel and cover panel proceed
as follows:
1. Close main gas supply valve.
2. Open flip-down cover of front enclosure panel (by
exerting slight pressure with fingertip) and switch
off system on/off switch.
3. Turn off power supply to boiler and ensure that
power supply cannot be activated during the duration
of the start-up/service work.
4. Loosen and remove screw 1holding enclosure panel
in place.
5. Remove front enclosure panel 2.
6. Remove cover panel 3 by unlocking the four pull-
down latches located on both the top and bottom of
the panel, and slide out panel.
To reinstall cover panel and front enclosure panel proceed
as follows:
1. Slide cover panel 2 over the top edge of supporting
panel 1.
2. Make sure that end edge of cover panel 2 is fully
inserted and is seated properly in groove 3.
3. Lock latches 4, one set at a time (starting with
either the top or bottom set of latches).
4. Mount front enclosure panel and secure in place with
screw.
WARNING
Failure to do so can result in damage to front
enclosure panel of boiler.
Removing front enclosure panel and cover panel
Reinstalling the cover panel

Vitodens 200 WB2 Service
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5285 538 - 01
Fill Heating System with Water
General Information
1. Open system isolation valves (if installed).
Note: Before filling the heating system with water,
check that all necessary flow check valves are
installed.
2. Check inlet pressure of the diaphragm expansion
tank. If the nitrogen pressure of the precharged
expansion tank is less than the static pressure of
the system, inflate membrane pressure to slightly
exceed pressure of system.
The static pressure required at the tank is based
upon the static height of the system. The system
fill pressure value must be equal to the expansion
tank pressure value at approx. 60ºF/15.6ºC.
3. To remove debris and/or sludge ensure that the
system piping is flushed out. Failure to do so could
cause settlement in the boiler causing overheating
and damage not covered by warranty.
System fill pressure must be approximately 3 psig
higher than the static head when the system is cold.
4. Fill the heating system with water at the boiler filling
and drain tap Aand drain air completely from the
system at manual air bleed valve B (use supplied key)
as per the Vitodens 200 Installation Instructions.
Max. boiler operating pressure ......45 psig
Min. boiler operating pressure .......12 psig
Pressure relief valve ....................30 psig
Only if applicable: Before draining/venting, pull the safety
cap (yellow cap) off the electromagnetic drive, reverse
the safety cap C and put it back on again (switching
valve in center setting).
After draining/venting the system, the safety cap must be
returned to its original position. Water treatment should
be considered in areas where it is known that boiler feed
water contains a high mineral content and hardness.
In areas where freezing might occur, an antifreeze may
be added to the system water to protect the system.
Please adhere to the specifications given by the antifreeze
manufacturer.
Do not use automotive silicate-based antifreeze. Please
observe that an antifreeze/water mixture may require
a backflow preventer within the automatic water feed and
influence components such as diaphragm
expansion tanks, radiation, etc. A 40% antifreeze content
will provide freeze-up protection to -10°F/-23°C.
Do not use antifreeze other than specifically made for
hot water heating systems. System also may contain
components which might be negatively affected by
antifreeze.
Check total system frequently when filled with antifreeze.

Vitodens 200 WB2 Service
5285 538 - 01
8
Fill Heating System with Water (continued)
General Information
Note: The outer conductor “L “ and the neutral conductor
“N” must not be interchanged.
See wiring diagram in section entitled “Additional
Information” in this manual.
In Canada all electrical wiring is to be done in accordance
with the latest edition of CSA C22.1 Part 1 and/or local
codes. In the U.S. use the National Electrical Code ANSI/
NFPA 70. The heating contractor must also comply with
both the Standard for Controls and Safety Devices for
Automatically Fired Boilers, ANSI, ASME CSD-1.
5. Check system pressure.
6. Shut off the boiler from the heating system on
heating water side (close shutoff valves).
7. Connect drain hose to manual air bleed valve B
located on top of the Vitodens 200 boiler.
8. Open ball valve Aand manual air bleed valve B
and vent the boiler with system pressure until noise
due to the presence of air is eliminated.
9. Close ball valve Aand manual air bleed valve B,
and open the heating water shutoff valves.
10. Check system pressure.
11. Ensure proper/adequate fuel supply exists.
Open gas shutoff valve.
Minimum system pressure is 12 psig.
Mark this value on the manometer.
Check Power Supply Connection
IMPORTANT A power module is supplied with the Vitodens 200 boiler,
which requires a 120VAC power supply from a wall
receptacle.
The module contains a 120/230 VAC step-up transformer
to power the Vitodens 200 with 230 VAC. Refer to the
Installation Instructions shipped with the module for
wiring details and/or Installation Instructions of the boiler.
Voltage range
The voltage at connector fÖ must be 230V
(see wiring diagram).
Neutral conductor
The electrical power supply must have a neutral
conductor.

Vitodens 200 WB2 Service
9
5285 538 - 01
Start-up and Service
Select Language (if required)
Heating Contractor Address Input
Comfortrol menu-driven programming unit
Open cover:
Menu option Button
/SYSTEM ”D”
/FACTORY SETTING ”A”
/LANGUAGE ”C”
Select language.
Comfortrol menu-driven programming unit.
This option allows the system user to access name and
telephone number of the heating contractor on the display
(see Vitodens 200 Operating Instructions) almost
immediately after a system fault has occurred.
Open the cover:
Menu option Button
/SYSTEM ”D”
/INSTALLER SETUP ”C”
/CODE PLEASE: ”B-C-C-B”
/DIAGNOSIS ”A”
/HEATING CONTRACTOR ”C”
Position cursor as required using the ”A” and ”B” buttons.
Select the required characters (number, letter, special
character) by turning the ”G” selector knob (turn
clockwise or counterclockwise).
Sequence of available characters:
0 1 2 3 4 5 6 7 8 9 A B C D E F G H I J K L M N O P Q R
S T U V W X Y Z = < > . : k ? , – i / ( )
Characters already selected can be deleted with the space
character ”k” or overwritten with another character.
Upon exiting the input menu (INSTALLER SETUP ”C”),
name and telephone number of the heating contractor are
automatically stored.

Vitodens 200 WB2 Service
5285 538 - 01
10
Start-up and Service
Select Appropriate Gas Type
1. Ensure that the fuel type listed on the boiler rating
plate is the correct type for the installation being
attempted.
2. Record fuel type in Maintenance Record on page 73.
The Vitodens 200 boiler is for use with gases whose
characteristics fall within the following ranges.
Do not use any other types of gas.
Natural gas Propane gas
Heating value (gross)
Btu/ft3
970 to 1100 2466 to 2542
Specific gravity 0.57 to 0.70 1.522 to 1.574
Ultimate carbon dioxide
(CO2) %
11.7 to 12.2 13.73 to 13.82
Measure Static Pressure and Running Pressure
IMPORTANT
A CO measurement (see page 13) must be taken before
and after working on gas appliances to eliminate risks to
health and to guarantee the satisfactory condition of the
system.
IMPORTANT
The burner is automatically ignited and starts operation
after a safety time has elapsed.
During initial start-up, the unit may indicate a fault
because of air in the gas supply pipe (especially for
propane gas).
After approx. 5 seconds, press the ”EU” button to reset
the burner. The ignition procedure is repeated. This boiler
employs a direct spark ignition system.
Static pressure
1. To measure static and/or running pressure remove
burner cover panel as per the removal and
reinstallation instructions on page 6 in these
instructions.
2. Close gas shutoff valve (field supplied).
3. Loosen screw in test nipple ”PE”Aon the gas
combination valve, do not remove completely.
Connect manometer.
4. Open the gas shutoff valve.
5. Measure static pressure. Values must be:
14 “w.c. max. for NG
14 “w.c. max. for LP
6. Enter measured value into Maintenance Record on
page 80 in this manual.
7. Start up boiler, using the on/off switch on the boiler
control.
Measuring static gas supply pressure, using test nipple “PE”

Vitodens 200 WB2 Service
11
5285 538 - 01
Start-up and Service
Measure Static Pressure and Running Pressure (continued)
Running pressure
8. Measure the running pressure; value must be:
Use suitable measuring instruments calibrated with
a minimum resolution of 0.04 “w.c. for measuring
the running pressure.
Running supply pressure with Corrective action
Natural gas Propane gas
under 4 ”w.c. under 11 ”w.c. Do not attempt
adjustment. Call local
gas utility to increase
pressure.
4 to 14 “w.c. 11 to 14 ”w.c. Start up boiler.
over 14 ”w.c. over 14 ”w.c. Do not attempt
adjustment. Call local
gas utility to decrease
pressure.
Boiler valve must not
be exposed to pressure
over 14 ”w.c.
9. Enter gas type into Maintenance Record on page 80
in this manual.
10. Switch off the heating system on/off switch on the
boiler control unit (boiler is shut down), close the
gas shutoff valve, remove the manometer and
re-tighten the screw in the test nipple ”PE” A.
Measuring static gas supply pressure, using test nipple “PE”
WARNING
Ensure that there is no open flame in the room.
WARNING
Never purge a gas line into a combustion chamber.
Never use matches, candles, flame, or other sources of
ignition for purpose of checking leakage. Use a soap and
water solution to check for leakage. A failure to follow
this warning could result in fire, explosion, personal injury
or loss of life.

Vitodens 200 WB2 Service
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12
Start-up and Service
How the Vitodens 200 Boiler Operates...
The MatriX burner blower and the combination gas valve
are factory calibrated and pre-adjusted for optimum boiler
performance at all firing rates through a non-mechanical,
pneumatic modulating link between combustion air and
gas flows.
Blower speed is automatically increased or decreased
based on heat demand and venting system resistances,
thereby regulating the amount of combustion air drawn.
The pneumatic modulating link between air and gas
introduces the required amount of gas for correct
combustion to meet the current heat demand, based on
a linear relationship between ∆P air and ∆P gas.
Optimum combustion air flow rate is recognized
and monitored by the differential air pressure sensor
(transducer). The output voltage signal of the transducer
is analyzed for logic by the LGM 29.XX burner ignition
control unit. The LGM 29.XX unit contains pre-
programmed performance curves and operational safety
parameters unique for every boiler model.
See page 45 for sequence of operation.
Flue gas adaptation function
The Vitodens employs a flue gas adaptation function.
This unique function records, processes, and reacts in
real time to fluctuations in pressure drops in the vent pipe
during normal operation caused by partial pipe blockages
due to ice formation at the vent termination, debris and/or
sudden high winds. Such increase in pressure drop, if not
promptly corrected, will reduce the combustion air flow
rate, and hence lead to unstable combustion.
The differential air pressure sensor (transducer) records
such pressure drops and supplies voltage signals to
the LGM 29.XX burner ignition control unit which, in
turn (based on stored performance curves and safety
parameters), initiates prompt adjustment of the blower
rotational speed, thus readjusting the combustion air
flow rate for optimum combustion. The same automatic
adaptation logic applies if combustion air is reduced (or
increased) due to slower (or faster) blower speed resulting
from line voltage drops (or increases) below (or above) the
threshold of 85% (or 110%).
WARNING
FOR FACTORY CALIBRATING PURPOSES, THE
COMBINATION GAS VALVE IS EQUIPPED WITH
ADJUSTMENT SCREWS X AND Y.
DO NOT ATTEMPT TO ADJUST OR READJUST THESE
SCREWS. ANY ATTEMPT TO TAMPER WITH FACTORY
PRE-ADJUSTED SETTINGS WILL LEAD TO UNSTABLE
OPERATION AND WILL AFFECT BOILER WARRANTY.
Do not adjust screws X and Y!

Vitodens 200 WB2 Service
13
5285 538 - 01
Start-up and Service
Check CO2Setting
The Vitodens 200 boiler is factory preset for operation
with natural gas or propane. It is recommended that a
CO2check be performed at the boiler vent pipe adaptor
as part of the initial start-up/maintenance procedure.
The MatriX burner of the Vitodens 200 is preset for the
entire gas group. No adjustment or readjustment of the
burner is required.
Depending on the gas type, the CO2value lies within the
range of:
6.6 to 10.0% for natural gas
approx. 10.0% for LP
The CO2value measured must be compared with the
above CO2value ranges of the individual gas type.
If the CO2value measured lies more than 1% outside the
stated range for NG, or 0.5% outside the stated range
for LP, perform the following steps:
Check that correct orifice was used (see subsection
entitled “Check orifice size” on page 14 and section
“Technical Data” on page 44 of this manual).
Check the venting system for leaks (see subsection
entitled “Check venting system for leaks” on page 15
of this manual).
1. Connect flue gas analyzer to boiler vent pipe adaptor
A(”Flue gas” measurement opening).
2. Open the gas shutoff valve and start up the boiler.
3. Trigger a call for heat by adjusting the setpoint value.
Do not use the emissions test switch ”S”to trigger
a call for heat.
IMPORTANT
IMPORTANT
Control unit type
4. Select the lower rated
thermal load and check
the C02content
5. Select the upper rated
thermal load and check
the C02content If value
deviates by more than
1%, replace burner
6. Terminate the setting
mode
Control unit for weather-
compensated mode with
standard programming unit
• Select the required
heating program.
• Set rotary selector G
to the required value.
• Enter actual values into
the service report.
• Close the test port.
Control unit for weather-
compensated mode with
menu-guided Comfortrol
programming unit
SYSTEM “D”
INSTALLER
SETUP “C”
CODE PLS “B-C-C-B”
DIAGNOSIS “A”
RELAY TEST “A”
With menu item
CONTINUE “ A”
up to code
10: MODULATION
<ST.90> CLOSED BURNER
<ST.41> ON
With menu item
CONTINUE “A” up to code
11: MODULATION
<ST.90> OPEN BURNER
<ST.41> ON
• Close the programming
unit.
• Enter actual values into
the service report.
• Close the test port.

Vitodens 200 WB2 Service
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14
Start-up and Service
CAUTION
Always contact your gas utility to obtain the correct
heating value before clocking the meter.
Clock Natural Gas Meter
IMPORTANT
A boiler underfired by 5% is acceptable. Do not overfire
the boiler.
For example:
A Vitodens 200-W 8-32 boiler (124 000 Btu/h input)
requires 290 seconds to use 10 cu. ft. of natural gas.
After contacting the local utility, you will find the heating
value is 1000 Btu per cu. ft.
Therefore,
36 000/290 x 1000 = 124 000 Btu/h input.
Therefore, the boiler input is correct.
Burner input formulas
(for low altitude only):
INPUT=(3600÷t) x 1000 where
t=TIME (sec.) for 1 ft.3
INPUT=(3600 x .01 x 1000 x 35.31)÷T
where
T = TIME (sec.) for .01 m3 natural gas.
Check Orifice Size
Clock natural gas meter to verify input
1. Ensure all other gas equipment served by the meter
is turned off during timing of gas input to the
Vitodens 200 boiler.
2. Measure the time in seconds it takes for the boiler
to use 10 cu. ft. of gas. Divide 3600 x 10 by the
number of seconds and you get the number of cu. ft.
of gas used per hour. Multiply this number by the
heating value of the gas to obtain Btu per hour input.
1. Remove burner cover panel (if still installed) as per
the removal and reinstallation instructions on page
6 in this manual, and reinstall panel upon completion
of service work.
2. Loosen screws Aand take the gas orifice holder C
out of the fitting.
3. Read orifice size stamped on the orifice body and
cross-reference to table below. If wrong orifice is
installed, proceed to next step.
4. Push the gas orifice Bsideways out of the gas
orifice holder C. Snap new and correct gas orifice
into gas orifice holder and push into the gas train.
See section entitled “Technical Data” on page 44 of
this manual for information on gas orifices.
Place O-ring Ein groove on new gas orifice B.
5. Tighten screws A.
Tighten to a torque of 1.1 lb.ft./1.5 Nm.
6. Check all gas connections for leaks with an approved
leak test solution.
IMPORTANT
Overview of orifices
Boiler model WB2 6-24C WB2 6-24 WB2 8-32
Natural gas E24 E24 E32
Liquid propane P24 P24 P32

Vitodens 200 WB2 Service
15
5285 538 - 01
Start-up and Service
Check all Primary and Secondary Circuit Connections for Leaks
Check heating system and domestic hot water
connections (if applicable). Ensure all connections are
pressure tight.
Correct any leaks found on fittings, pumps, valves, etc.
Perform Combustion Analysis
Check Venting System for Leaks (circular air gap measurement)
IMPORTANT
A CO measurement (see page 13) must be taken before
and after working on gas appliances to eliminate risks to
health and to guarantee the satisfactory condition
of the system.
Record the measured combustion values in the sequence
stated in the Maintenance Record on page 80 in this
manual.
Viessmann strongly recommends that the heating
contractor perform a simplified leak test during boiler
start-up. For this purpose it is sufficient to measure
the Bconcentration of the combustion air in the
coaxial gap of the air intake pipe. The vent pipe is
considered sufficiently leak-proof if a CO2concentration
in the combustion air no higher than 0.2% or an O2
concentration no lower than 20.6% is measured.
If higher CO2values or lower O2 values are measured,
check venting system thoroughly.
Note: The vent pipe adaptor comes with two
measurement ports, one for combustion air-intake
measurement and one for flue gas measurement.
A Combustion air measuring point

Vitodens 200 WB2 Service
5285 538 - 01
16
Start-up and Service
Visually Check the Exterior of the Burner Mesh Assembly
Disassemble Burner and Check Burner Gasket
1. Remove burner cover panel (if still installed) as per
the removal and reinstallation instructions on page
6 in this manual, and reinstall panel upon completion
of service work.
2. Switch off the heating system switch on the control
unit and the power supply.
3. Close gas shutoff valve and secure.
4. Disconnect electrical cables from fan motor A,
differential air pressure sensor B, combination gas
valve C, ionization electrode D, ignition transformer
Eand grounding F.
5. Remove two screws Gto disconnect gas line from
gas valve.
6. Loosen four flange locknuts H and remove burner.
7. Check burner gaskets for damage (see Parts List) and
replace if required.
To check the exterior of the burner mesh assembly for
physical damages, such as dents, corrosion and/or
abnormally large holes:
1. Remove burner cover panel, if still installed (see
page 6). Reinstall panel upon completion of service
work.
Do not replace gasket D when visually inspecting the
exterior of the mesh assembly.
Replace Burner Mesh Assembly (if wire mesh is damaged)
1. Remove electrodes A.
2. Unscrew the six Torx screws B and remove burner
mesh assembly C.
3. Remove existing burner mesh assembly gasket D.
4. Fit new burner mesh assembly with the new gasket
and tighten with the six Torx screws.
Tighten to a torque of 2.5 lb.ft. / 3.5 Nm.
CAUTION
Always contact your gas utility to obtain the correct
heating value before clocking the meter.
IMPORTANT

Vitodens 200 WB2 Service
17
5285 538 - 01
Check and Adjust Ignition and Ionization Electrode
Start-up and Service
CAUTION
Do not damage wire mesh when cleaning.
1. Remove burner cover panel (if still installed) as per
the removal and reinstallation instructions on page
6 in this manual, and reinstall panel upon completion
of service work.
2. Check electrodes for wear and contamination.
3. Clean electrodes with small brush or emery paper.
4. Check clearances. If clearances are not satisfactory
or the electrodes are damaged, replace electrodes and
gasket Aand align.
Tighten fastening screws for the electrodes to a
torque of 1.5 lb.ft. / 2 Nm.
Check Condensate Drain
Ensure condensate drains freely (e.g. at siphon trap A).
If necessary, clean siphon trap.
If the condensate does not drain freely, condensate will
accumulate in bottom part of boiler resulting in a burner
shut-down (fault message).
Installation Instructions Neutralization Unit
(if applicable)

Vitodens 200 WB2 Service
5285 538 - 01
18
Check Neutralization Unit (if applicable)
WARNING
Follow cleaning agent manufacturer’s safety instructions
and wear appropriate protective equipment.
Start-up and Service
Clean Combustion Chamber/Heat Exchanger Surfaces, and Mount Burner
1. Remove burner cover panel (if still installed) as per
the removal and reinstallation instructions on page 6
in this manual, and reinstall panel upon completion of
service work.
2. If necessary, clean the combustion chamber Aand
heat exchanger surfaces Bwith a brush and/or rinse
with water.
Use solvent-free cleaning agents to remove residues:
Remove deposits of soot with alkaline agents
containing tenside.
Remove coatings and (yellowish brown) surface
discoloration with phosphoric acid-based “Antox
75 E Plus”, or citric acid-based CitriSurft 3050
by Stellar Solutions Inc.
Rinse thoroughly with water.
3. Mount burner and tighten diagonally to a torque of
2.8 lb.ft. / 4 Nm (four flange locknuts).
Note: Be careful not to scratch parts which are in
contact with flue gas. Use plastic brushes, not
wire brushes!
Follow Material Safety Data Sheet (MSDS) of
the cleaning agent manufacturer.
The cleaning agents must not contain
hydrocarbon-based solvents or potassium.
4. Fasten threaded connection for the gas connection
hose with a new gasket or O-ring.
Perform leak test.
5. Connect electrical cables to corresponding parts.
IMPORTANT
1. Check the pH value of the condensate with pH
measuring strip. If the pH value is less than 6.5,
replace granulate.
pH measuring strip must be field supplied.
2. If contaminated: Rinse neutralization unit with tap water.
3. Add granulate as marked.
The granulate is consumed as it neutralizes the condensate.
The red marking indicates the min. filling level.
Installation Instructions Neutralization Unit.
IMPORTANT
IMPORTANT

Vitodens 200 WB2 Service
19
5285 538 - 01
Check Flow Rate Limiter and Water Flow Switch Filter (for Combi boiler only)
Start-up and Service
1. Loosen threaded connection of the cold water pipe
at the water flow switch A.
2. Loosen threaded connection at the cold water
connection nipple B.
3. Take out cold water connection nipple Cwith the
water filte D.
4. Check the flow rate limiter Ein the connection
nipple C; if limescale is present or if damaged,
replace connection nipple.
5. If required, clean water filter D. Apply moderate
amount of supplied lubricant to gasket/O-ring.
6. Reassemble in reverse sequence.
Check Diaphragm Expansion Tank and System Pressure
Perform check with the system cold.
1. Drain boiler/system and reduce pressure until the
manometer reading is ”0”.
2. If the nitrogen pressure of the precharged expansion
tank is less than the static pressure of the system,
inflate membrane pressure to slightly exceed pressure
of system.
The static pressure required at the tank is based upon
the static height of the system. The system fill
pressure value must be equal to the expansion tank
pressure value at approx. 60ºF/15.6ºC.
Example:
Static head of 33 ft./10 m (distance between boiler
and topmost heat emitter surface) corresponds to a
static pressure of 1 bar/15 psig.
3. Top up with water until filling pressure is higher than
the inlet pressure of the diaphragm expansion tank.
With the system cold, the filling pressure must be
approx. 3 psig higher than the static pressure.
Max. operating pressure: .............45 psig
Min. operating pressure: ..............12 psig
4. When starting up the system for the first time, mark
this value as the minimum filling pressure on the
manometer. A lower manometer reading usually
indicates loss of water due to leakage. All leaks must
be repaired.

Vitodens 200 WB2 Service
5285 538 - 01
20
Check Functioning of Safety Valves
Check Electrical Connections
Check Gas Pipes and Fittings for Leaks
Start-up and Service
CAUTION
Ensure all joints of gas line are pressure tight and that
gas valves do not leak when under normal operating
pressure (use approved leak detection liquid).
WARNING
The gas supply piping must be leak tested before placing
the boiler in operation.
Ensure proper operation of low water cut-off(s)
(if applicable), pressure relief valve, and pump(s).
Check pressure gage, air vent and pressure relief valve.
Ensure that pressure relief valve does not leak and
that it operates in accordance with information provided
by the manufacturer.
Refer to maintenance instructions supplied with low water
cut-offs, pumps, etc.
Flush float water type low water cut-offs (if used).
Follow local regulations with respect to backflow
preventers.
If oil-lubricated pumps are used, ensure proper lubrication.
If motorized zone valves are used, refer to maintenance
instructions provided with zone valves.
Ensure all plug-in connectors and strain reliefs make
positive contact and are seated properly.
Installation Instructions Power Module