Viessmann VITOFLEX 300-UF Installation and user guide

Service and
Maintenance Instructions
for use by engineers and heating contractors
5797 346 - 01 08/2017
Read and save these instructions
for future reference.
Vitoflex 300-UF 390, 530, 720, 950 AND 1250
Wood-fired Boiler
Output range: UF 390, 334 to 1331 MBH (98 to 390 kW)
UF 530, 450 to 1808 MBH (132 to 530 kW)
UF 720, 614 to 2457 MBH (180 to 720 kW)
UF 950, 812 to 3242 MBH (238 to 950 kW)
UF 1250, 1065 to 4265 MBH (312 to 1250 kW)
Vitoflex 300-UF
Product may not be exactly as shown
If the information in this manual is not
followed exactly, a fire or explosion
may result causing property damage,
personal injury or loss of life.
Improper installation, adjustment and/or
operation could cause carbon monoxide
poisoning resulting in injury or loss of life.
This product must be installed and serviced
by a professional service technician who is
experienced and qualified in hot water boiler
installation and wood fuel combustion.
Do not store or use gasoline or other
flammable fluids in the vicinity of this or
any other appliance.
WHAT TO DO IF YOU SMELL FLUE GAS
Deactivate heating equipment
Open windows and doors.
Inform your heating contractor
Please file in Service Binder
WARNING
WARNING
IMPORTANT
H

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Safety, Installation and Warranty Requirements
WARNING
Installers must follow local regulations with respect to
installation of carbon monoxide detectors. Follow the
manufacturer’s maintenance schedule of the boiler
contained in the section “Cleaning and Maintenance”.
Please ensure that these instructions are read and understood before commencing service and/or maintenance. 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).
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”.
Contaminated air
Air contaminated by chemicals can cause by-products
in the combustion process, which are poisonous to
inhabitants and destructive to Viessmann equipment.
For a listing of chemicals which
cannot be stored in or near the
boiler room, please see subsection
entitled “Mechanical Room”.
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.
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, refer to
the “Installation and Operating Instructions”.
Fresh air
This equipment requires fresh air for
safe operation and must be installed
ensuring provisions for adequate
combustion and ventilation air exist.
For information pertaining to the
fresh air requirements of this product,
please see subsection entitled
“Combustion Air Supply”.
Equipment venting
Never operate the boiler without an installed venting
system. An improper venting system can cause
carbon monoxide poisoning.
For information pertaining to venting
and chimney requirements, refer to the
“Installation and Operating Instructions”.
All products of combustion must be
safely vented to the outdoors.
Introduction

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Vitoflex 300-UF Service & Maintenance Introduction
About these 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.
CAUTION
Cautions draw your attention to the presence of potential
hazards or important product information.
WARNING
Warnings draw your attention to the presence of potential
hazards or important product information.

IMPORTANT
Indicates an imminently hazardous situation which,
if not avoided, could result in death, serious injury or
substantial product/property damage.
Indicates an imminently hazardous situation which,
if not avoided, may result in minor injury or product/
property damage.
Helpful hints for installation, operation or maintenance
which pertain to the product.
This symbol indicates to note additional information.
This symbol indicates that other instructions must be
referenced.
Note: Viessmann Manufacturing Company Inc. reserves
the right to make product changes or updates
without notice and will not be held liable for
errors or omissions in the product literature.

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Vitoflex 300-UF Service & Maintenance
Table of Contents
Introduction
General Information
Safety
Maintenance
Troubleshooting
Page
Safety, Installation and Warranty Requirements..............2
About these Instructions..............................................3
Product Information....................................................5
Important Regulatory and Installation Requirements ........6
Safety Instructions......................................................8
Carbon Monoxide........................................................9
Extreme Weather Conditions......................................10
Hazardous Material....................................................11
Mechanical Room.....................................................12
Combustion Air Supply..............................................13
Information on Maintenance......................................14
Responsible Groups..................................................14
Annual General Inspection..........................................14
Components of the Biomass Boiler..............................15
Servicing the Boiler...................................................16
Cleaning the Boiler....................................................18
Cleaning..................................................................20
Feed Systems...........................................................25
Shutdown...............................................................26
Warning Message......................................................27
Fault Messages.........................................................28
Adjusting the Fuel Supply and Air Supply.....................30
Adjusting the Ash Removal........................................30
Visual Inspection of Combustion.................................31
Unjamming the Ash Removal Screw Conveyor..............31
Operating Date.........................................................32
I/O Modules.............................................................32
Manual Mode and Other Scans...................................33
Keys for Manual Mode..............................................33
Fuel...........................................................................34
Secondary Air.............................................................34
Flame......................................................................35
Flow.......................................................................35
Flue Gas Fan............................................................35

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Maximum allowable working pressure (water)…30 or 60 psi
Maximum water temperature…250°F (120°C) (closed loop)
Maximum boiler temperature……210°F (99°C) (open loop)
This boiler does not require a flow switch.
Codes
CSA B366.1-M91
Solid Fuel Fired Central Heating Appliances
CSA C22.2 NO. 3-M1988 (latest edition)
Electrical Features of Fuel Burning Equipment
UL2523
Solid Fuel-Fired Hydronic Heating Appliances, Water
Heaters and Boilers
CSA B365 (latest edition)
Installation Code for Solid Fuel Burning Appliances
and Equipment
ASME section IV boilers and pressure vessels.
Viessmann solid-fuel boiler can only be installed and
serviced by qualified trained personnel.
Steel wood-fired hot water heating boiler.
For operation primarily with modulating boiler water
temperatures in closed loop forced circulation hot water
heating systems. Under certain conditions, open loop
systems may also be considered. Contact Viessmann
for details.
WARNING
Exposing the boiler to pressures and temperatures in
excess of those listed will result in damages and will
render the warranty null and void.
Product Information
General Information

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Important Regulatory and Installation Requirements
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.
Ensure main power supply to equipment, the heating
system, and all external controls have been deactivated.
Take precautions to avoid accidental activation of power
during service work.
Technical literature
Literature applicable to all aspects of the Vitoflex 300-UF
wood-fired boiler:
- Installation and Operating Instructions
- Service and Maintenance Instructions
- Field Wiring Diagram
The completeness and functionality of field supplied
electrical controls and components must be verified
by the heating contractor. These include low-water
cutoffs, flow switches (if used), staging controls,
pumps, motorized valves, air vents, thermostats, etc.
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.
Please carefully read this manual prior to attempting
service and maintenance. 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.
General Information
RISK OF INJURY: Shut the system off before starting
any cleaning. Be absolutely sure to wear protective
gloves, protective eyewear if required and use the
cleaning tools that come with the system (danger of
blow-ups, burns and getting crushed)!
CAUTION

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Vitoflex 300-UF Service & Maintenance General Information
WARNING
The boiler must not be located in areas or rooms where
chemicals are stored, or aggressive vapors from (i.e.
bleach, hair spray, methyl chloride, carbon tetrachloride
or perchloroethylene) or high dust levels or humidity
levels are present. Heat exchanger corrosion might
occur and reduce the lifetime of the boiler significantly.
If above criteria are not properly observed and boiler
damage results, any warranty on the complete boiler
and related components will be null and void.
Important Regulatory and Installation Requirements (continued)
Regular maintenance and service
The entire heating system must be cleaned and serviced
on a regular basis by a qualified contractor or service
agency to ensure reliable, energy-efficient, and
environmentally friendly operation.
The build-up of soot on the heat exchanger raises the
flue gas temperature and reduces efficiency.
IMPORTANT
Keep boiler and boiler room clear and free of combustible
materials, gasoline and other flammable vapors and
liquids. Do not obstruct the flow of combustion and
ventilation air. All inspection, maintenance and service
must be performed by a qualified heating contractor.
WARNING
Improper installation, adjustment, service, or maintenance
can cause flue products to flow into living space. Flue
products contain poisonous carbon monoxide gas, which
can cause nausea or asphyxiation resulting in severe
personal injury or loss of life.
Important to know
Do not use this boiler if any part has been under, or
exposed to, water. Immediately call a qualified heating
contractor to inspect the boiler and to replace any part
of the control system, which has been under or exposed
to water.
WARNING
Service and maintenance can only be performed by a
qualified heating contractor.

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Vitoflex 300-UF Service & Maintenance
IMPORTANT
The local building codes and regulations must be followed
by the heating contractor.
IMPORTANT
Please refer to the Installation and Operating
Instructions for installation, commissioning
and technical specification information. The
Installation and Operating Instructions contain
the necessary safety and national/local code
requirements which, if not followed exactly,
may lead to property damage, personal injuries
and/or death.
Important Information
Safety instructions
When carrying out work on the heating system, such as
cleaning and maintenance, wear appropriate protective
equipment when required.
There is a danger of getting injured through: burning,
knocking against corners and edges, crushing in moving
parts and noise.
Power supply: 120/1/60, 208/1/60 and 240/1/60
In case of an emergency, the Vitoflex 300-UF can be
disconnected from the electrical power supply at all the
leads by the main switch on the control cabinet.
CAUTION
FIRE HAZARD:
The boiler must NEVER be operated with the doors open!
Any burning bits that escape could start a fire.
RISK OF INJURY:
If the doors are open during operation, sparks or flames
could leap out.
Equipment for dissipating excess heat: a competent
specialist should examine the operational reliability of
the thermal safety flush valve annually. The safety
heat exchanger must not by any means be used as an
operational heat exchanger.
Seals: for the functioning and controllability of the boiler,
it is important that no unwanted air can enter unchecked
through leaks.
The doors and lids have to shut tight - any damaged
seals must be replaced immediately. Tighten the retaining
screws and handles well.
Operation, cleaning and maintenance: bear in mind that
even the best product can only fulfill its functions well,
doing so for a long time and free of malfunctions, if
operated and maintained properly.
Compliance with the “Cleaning” section is mandatory!
Safety Instructions
IMPORTANT
Doors: for safety keep firing and ash pit doors tightly closed
Safety
If you notice fire coming from the appliance, call the fire
department immediately!
DO NOT attempt to extinguish the fire unless qualified to
do so.
WARNING
Fire causes a risk of burns and explosion!
Shut down the boiler
Close fuel shut-off valves
Use a tested fire extinguisher, class ABC.

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Carbon monoxide
The U.S. Consumer Product Safety Commission strongly
recommends the installation of carbon monoxide detectors
in buildings in which gas-burning equipment is installed.
Carbon monoxide (CO) is a colorless, odorless gas, which
may be produced during incomplete combustion of fuel
and/or when the flame does not receive an adequate
supply of combustion air. Carbon monoxide can cause
severe personal injury or loss of life.
Therefore, carbon monoxide detectors that are in
compliance with a nationally recognized standard
(e.g. ANSI/UL 2034-2002, CSA 6.19-01) should be
installed and maintained in buildings that contain
gas-burning equipment.
Note: Viessmann does not test any detectors and makes
no representation regarding any brand or type of
detector.
For safe operation
We recommend that you frequently:
- Check for debris which could obstruct the flow of
flue gases. The vent or chimney must not be blocked.
A blocked or partially blocked vent or chimney can
cause flue gases to leak into the structure. Flue gases
leaking into the house can cause injury or death.
Blocked or partially blocked chimneys must have the
blockage removed by a qualified heating contractor.
- Check pressure gage for correct system (water)
pressure. Check for water on the floor from the
discharge pipe of the pressure relief valve or any
other pipe, pipe joint, valve or air vent.
- Check for moisture, water, or appearance of rust
on the flue gas pipes, their joints as well as vent
dampers, or side wall vent terminals (if so equipped).
- Ensure that nothing is obstructing the flow of
combustion and ventilation air and no chemicals,
garbage, gasoline, combustible materials, flammable
vapors and liquids are stored (not even temporarily)
in the vicinity of the boiler.
- DO NOT allow unsupervised children near the boiler.
Service/inspection of the boiler and the system must be
performed on a regular basis. Maintenance, service and
cleaning are specified in the section on maintenance.
Before the heating season begins, it is recommended that
the boiler be serviced by a qualified heating technician.
WARNING
Improper installation, adjustment, service, or maintenance
can cause flue products to flow into living space. Flue
products contain poisonous carbon monoxide gas, which
can cause nausea or asphyxiation resulting in severe
personal injury or loss of life.
WARNING
The operator/ultimate owner is required to have the heat-
ing boiler and controls checked, as a minimum once per
year, by the original installer or by a competent heating
contractor familiar with the equipment. Defects must be
corrected immediately.
Carbon Monoxide
Safety

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Extreme Weather Conditions
Safety
WARNING
As there are no user-serviceable parts on the boiler,
or control, the end-user must not perform service
activities of any kind on system components. Failure
to heed this warning can cause property damage,
severe personal injury or loss of life.
Frozen water pipe hazard
Your heating boiler is designed to provide a warm and
comfortable living environment. It is NOT designed to
ensure against freezing of water pipes. The boiler is
equipped with several safety devices that are designed
to shut down the boiler and to prevent it from restarting
in the event of various unsafe conditions.
If your boiler remains off for an extended period of time
during cold weather, water pipes may freeze and burst,
resulting in extensive water damage and conditions in
which mold could grow. Certain molds are known to
cause respiratory problems, as well as to pose other
serious health risks. In case of water damage, immediate
measures should be taken to dry out affected areas as
quickly as possible to prevent mold from developing.
If your home will be unattended for an extended period
of time during cold weather, you should...
Shut off the water supply to the building, drain the water
pipes and add antifreeze for potable water to drain traps
and toilet tanks. Open faucets where appropriate.
or…
Have someone check the building frequently during cold
weather and call a qualified service agency if required.
or...
Install a reliable remote temperature sensor that will
notify somebody of freezing conditions within the home.

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WARNING
Inhaling of fiberglass wool and/or ceramic fiber materials
is a possible cancer hazard. These materials can also
cause respiratory, skin and eye irritation.
Fiberglass wool and ceramic fiber materials
WARNING
Appliance materials of construction, products of
combustion and the fuel contain alumina, silica, heavy
metals, carbon monoxide, nitrogen oxides, aldehydes
and/or other toxic or harmful substances which can
cause serious injury or loss of life and which are known
to the State of California to cause cancer, birth defects
and other reproductive harm. Always use proper safety
clothing, respirators and equipment when servicing or
working nearby the appliance.
The state of California has listed the airborne fibers of
these materials as a possible cancer hazard through
inhalation. When handling these materials, special care
must be applied.
First aid measures
- If eye contact occurs, flush eyes with water to
remove dust. If symptoms persist, seek medical
attention.
- If skin contact occurs, wash affected areas gently
with soap and warm water after handling.
Hazardous Material
Safety
Suppliers of ceramic fiber products recommend the
following first aid measures:
- Respiratory tract (nose and throat) irritation:
If respiratory tract irritation develops, move the
person to a dust free location.
- Eye irritation: If eyes become irritated, flush
immediately with large amounts of lukewarm water
for at least 15 minutes. Eyelids should be held away
from the eyeball to ensure thorough rinsing.
Do not rub eyes.
- Skin irritation: If skin becomes irritated, remove soiled
clothing. Do not rub or scratch exposed skin.
Wash area of contact thoroughly with soap and water.
Using a skin cream or lotion after washing may be
helpful.
- Gastrointestinal irritation: If gastrointestinal tract
irritation develops, move the person to a dust free
environment.
Suppliers of fiberglass wool products recommend the
following precautions be taken when handling these
materials:
- Avoid breathing fiberglass dust and contact with
skin and eyes.
- Use NIOSH approved dust/mist respirator.
- Wear long-sleeved, loose fitting clothing, gloves
and eye protection.
- Wash work clothes separately from other clothing.
Rinse washer thoroughly.
- Operations such as sawing, blowing, tear-out and
spraying may generate airborne fiber concentration
requiring additional protection.

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Vitoflex 300-UF Service & Maintenance
Safety
IMPORTANT
WARNING
Incorrect ambient conditions can lead to damage to
the heating system and put safe operation at risk.
Mechanical room conditions
Prevent the air from becoming contaminated by
homogenate hydrocarbons (e.g. as contained in paints
solvents or cleaning fluids) and excessive dust (e.g.
through grinding or polishing work). Combustion air for
the heating process, and ventilation of the boiler room
must be free of corrosive contaminants. To that end, any
boiler must be installed in an area that has no chemical
exposure. The list to the right indicates the main,
currently known sources.
Avoid continuously high levels of humidity (e.g. through
frequent drying of laundry).
Never close existing ventilation openings.
Components which are not tested with the heating
system may damage the heating system or affect its
functions. Installation or replacement may only be
carried out by a qualified heating contractor.
Sources of combustion and ventilation air contaminants
Areas likely to contain contaminants:
- New building construction
- Swimming pools
- Remodeling areas, hobby rooms
- Garages with workshops
- Furniture refinishing areas
- Dry cleaning/laundry areas and establishments
- Auto body shops
- Refrigeration repair shops
- Metal fabrication plants
- Plastic manufacturing plants
- Photo processing plants
- Beauty salons
Products containing contaminants:
- Chlorine-type bleaches, detergents and cleaning
solvents found in household laundry rooms
- Paint and varnish removers
- Hydrochloric acid, muriatic acid
- Chlorine-based swimming pool chemicals
- Spray cans containing chlorofluorocarbons
- Chlorinated waxes and cleaners
- Cements and glues
- Refrigerant leaks
- Calcium chloride used for thawing
- Sodium chloride used for water softening salt
- Permanent wave solutions
- Adhesives used to fasten building products and
other similar item
- Antistatic fabric softeners used in clothes dryers
Mechanical Room
IMPORTANT
Always follow the most up-to-date local, municipal and
building regulations and codes.
No combustible materials may be stored in the heating
room. The heating boiler may only be set up on a fire-
resistant and temperature-resistant floor. No temperature-
sensitive pipes or lines may be installed in the floor
beneath the heating boiler.
A sufficient supply of fresh air must be provided directly
from outdoors into the heating room. Induced ventilation
is necessary for heating rooms that are confined or
enclosed. See “Installation and Operating Instructions”
for more details.
The temperature in the heating room must not exceed
104°F (40°C) while the system is in operation
(in the area approx. 3 ft. (1 m) away from the boiler).
The temperature in the heating room must not fall below
50°F (10°C) while the system is in operation (measured
at the inner side of exterior walls).

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Combustion Air Supply
Codes
Provision for combustion and ventilation air must be made
in accordance with applicable local codes.
In the absence of local codes, use:
CSA B365, Installation Code for Solid Fuel Burning
Appliances and Equipment.
Always use latest edition codes.
WARNING
Failure to provide an adequate supply of fresh combustion
air can cause poisonous flue gases to enter living space.
Flue gases entering living space can cause carbon
monoxide poisoning which can result in severe personal
injury or loss of life.
WARNING
Never cover the boiler or store debris or other materials
near the boiler, or in any way block the flow of adequate
fresh air to the boiler. Never cover the combustion air
opening. Advise system operator/ultimate owner
accordingly.
WARNING
The boiler must not be located in areas or rooms where
chemicals are stored or aggressive vapors (i.e. bleach,
hair spray, methyl chloride, carbon tetrachloride or
perchloroethylene) or high dust levels or humidity levels
are present. Heat exchanger corrosion might occur and
reduce the lifetime of the boiler significantly. If above
criteria are not properly observed and boiler damage
results, any warranty on the complete boiler and related
components will be null and void.
General
This equipment requires fresh air for safe operation.
The boiler location must never be under negative pressure.
Exhaust fans, attic fans, or dryer fans may cause air to be
exhausted at a rate higher than air can enter the structure
for safe combustion.
The heating contractor shall ensure all of the following
requirements are met:
- An adequate supply of combustion air must be
available to ensure proper combustion.
- Ambient air temperatures must be maintained within
safe operating limits.
- When a damper is provided in any opening intended
to admit combustion air into the room within which
the appliance is installed, the damper shall be
interlocked to prevent any boiler from starting
before the damper is fully open.
- Each duct used to convey air from the outdoors
shall have:
1. a cross-sectional area throughout its length at
least equal to the free area of the inlet and outlet
openings which it connects,
2. making a provision for outside combustion air,
the intake shall not be less than 1 ft. (0.3 m)
above the anticipated snow level for the location.
- The heating contractor must check with local
authorities (municipal building department) for
combustion air requirements particular to the area.
See “Installation and Operating Instructions” for more
details.

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Maintenance
Information on Maintenance
Note: Wear personal protective equipment.
Always wear a face mask when handling ash or slag.
WARNING
Missing protective covers pose a risk of crushing and
cutting injuries through entanglement in rotating or
moving parts.
After completing maintenance work, ensure that
all protective covers are re-installed correctly.
CAUTION
Serious injuries or risk to life through electric shock.
Switch OFF the mains isolator before starting any
maintenance on the heating system. Safeguard the
system against reconnection.
WARNING
Risk of burns due to hot system components
Only carry out maintenance work when the system
has cooled down.
CAUTION
Fuel emissions and incomplete combustion lead to
the formation of life threatening carbon monoxide
(CO). Carbon monoxide is a colorless, odourless and
tasteless, extremely poisonous gas, which in sufficient
concentration results in death.
Always wear a mobile CO monitor when entering the
fuel store, rooms where fuel is transported and the boiler
room. If the monitor sounds an alarm, leave the room
immediately.
Observe the safety instructions for the fuel store.
CAUTION
Risk to life if the system starts up unexpectedly.
Before restarting the system, ensure that no persons
are in the danger zone around the system.
Responsible Groups
Annual General Inspection
Maintenance jobs are carried out by various groups of
personnel. All personnel charged with working on the
heating system must be instructed with reference to
the documentation supplied.
The maintenance and cleaning schedules listed below
use the following symbols for each group.
Viessmann Technical Service is happy to carry out the
inspection and maintenance of your heating system
and can provide a quote for a maintenance contract.
Contact the Technical Service department for an
annual general inspection or if you wish to change fuel.
Costs for inspection and maintenance are met by the
operator.
Symbol Description
O Operator
V Viessmann Technical Service
HC Approved heating contractor

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Components of the Biomass Boiler
Legend
1In-feed auger with isolating layer
2Drive for moving grate
3Igniter
4Controlled combustion air supply system
5Moving grate
6Drive for automatic de-ashing assembly with ash
container (optional)
7Combustion chamber
8Combustion chamber door
9Pneumatic cleaning system (optional)
qP Heat exchanger door
qQ Safety heat exchanger for thermal safety flush valve
qW Heat exchanger
qE Frequency-controlled flue gas exhaust blower
Maintenance

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Maintenance
Servicing the Boiler
Component, activity Interval
1000
hours
1200
hours
Every
6 months
Annually
Boiler
Service electrical safety equipment HC
Service safety equipment on the water side HC
Pneumatic cleaning system A
Check valves for tightness O
Heat exchanger B
Check system pressure at pressure gauge
(minimum pressure, water shortage)
O
Check thermally activated safety valve for tightness O
Check gaskets on heat exchanger door O
Combustion chamber C
Check ash container connection for tightness O
Check grate for damage HC
Check fire bricks of combustion chamber door for cracks HC
Check refractory lining for damage O
Check refractory lining for slag deposits and remove slag where necessary O
Check intake aperture for secondary air O
Check flame temperature thermocouples for damage O
Check gaskets of combustion chamber door and ash removal system O

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Vitoflex 300-UF Service & Maintenance Maintenance
Component, activity Interval
1000
hours
1200
hours
Every
6 months
Annually
Ignition system D
Check ignition pipe for blockages and clean if necessary O
Service heating system HC
Compressor system (optional)
Service the compressor system in accordance with the compressor
operating instructions.
Note: If the compressor is operating continuously, this indicates that
there is a leak in the compressed air system. Check supply lines
and valves for leaks.
In the case of on-site supply of compressed air, ensure that the
compressor is suitable for continuous operation or can be prevented
from operating continuously.
O
(Interval in accordance with the
compressor operating instructions)
Servicing the Boiler (continued)

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Vitoflex 300-UF Service & Maintenance
Maintenance
Cleaning the Boiler
Information on cleaning the boiler
Note: Dirt and deposits can damage the boiler.
Clean the outside of the heating system as required.
Have the inside of the heating system cleaned at
least once a year by contractors.
Note: Check the lines and pipes of the flue gas path for
tightness after cleaning and every six months.
Note: Cleaning work may also be carried out by a local
chimney sweep.
Component, activity Interval
Daily 300
hours
900
hours
Annually
Heat exchanger A
Clean heat exchanger together with complete flue gas path and
reversing area B
O
Clean lambda probe CO
Clean primary air fan, secondary air fan and flue gas fan O
Check sight glasses of light barriers for dirt and clean if necessary.
When doing so, remove any deposits from the apertures for the
sight glasses
O

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5797 346 - 01
Vitoflex 300-UF Service & Maintenance Maintenance
Cleaning the Boiler (continued)
Component, activity Interval
Daily 300
hours
900
hours
Annually
Combustion chamber K
Check combustion block with grate D for dirt and slag deposits and clean
if necessary. Cleaning interval depends on fuel and fuel quality
O
Remove ash from under the infeed grate, the sloping grate and the
combustion retort E
O
Check ash level in ash removal channel F through the sight glass
and if necessary remove ash in manual mode.
Note: After cleaning, the ash removal screw conveyor must be covered
with ash again. This will protect the ash channel and the ash removal
screw conveyor from excessive temperatures.
If necessary, adjust the ash removal cycle via the controller.
O
Pneumatic cleaning and compressor system G
Drain condensate from the compressor system GO
Boiler
Combustion chamber Kand 2nd pass H: remove ash O

20
5797 346 - 01
Vitoflex 300-UF Service & Maintenance
Cleaning
Boiler
The heat exchanger, flue gas pipe, and chimney must be
cleaned regularly to remove accumulated creosote and ash.
Ensure that the heat exchanger, flue gas pipe, and
chimney are cleaned at the end of the heating season
to minimize corrosion during the summer months. The
appliance, flue gas pipe, and chimney must be in good
condition.
Regular cleaning and maintenance of the boiler system is
of the utmost importance to assure trouble-free operation
and to obtain the greatest possible output at the best
efficiency.
The cleaning intervals listed here are for wood chip fuel
with clinging bark with 0.8% ash content. The cleaning
intervals may vary, depending on the fuel, the amount
of fine matter and the operating conditions.
IMPORTANT
CAUTION
RISK OF INJURY - Shut the system off before beginning
any cleaning work. Be absolutely sure to wear protective
gloves, protective eyewear if required and use the cleaning
utensils that come with the system (danger of blow-ups,
burns and getting crushed)!
CAUTION
DANGER OF INJURY – be absolutely sure to turn OFF
main switch.
Never operate the boiler without the ash bin.
IMPORTANT
With pneumatic cleaning system, disconnect the
compressed air line before opening the boiler door –
danger of injury!
Check the level of the ash bin regularly and empty the bin
before it is completely full.
Maintenance