Viessmann VITOTRONIC 300-K User manual

for use by heating contractor
Please file in Service Binder
Product may not be exactly as shown
5516 971 - 03 04/2015
VITOTRONIC 300-K
Vitotronic 300-K, type MW2C
Multi boiler system with weather-compensated cascade control
Operating Instructions
Vitotronic 300-K
Read and save these instructions
for future reference.
IMPORTANT
Certified as a component
part for Viessmann boilers

Vitotronic 300-K Operating
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General
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.
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”.
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
“Mechanical room” in the “Installation
Instructions”.
Equipment venting
Never operate boiler without an installed venting
system. An improper venting system can cause
carbon monoxide poisoning.
For information pertaining to
venting and chimney requirements,
please see section entitled “Venting
Connection”. All products of
combustion must be safely vented
to the outdoors.
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.
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Page
Table of Contents
General
Safety
Operation
Start-up/Shutdown
Overview
Central Heating
DHW Heating
Further Adjustments
Scanning
Emissions
Troubleshooting
Scanning Options
Additional Information
Safety, Installation and Warranty Requirements..............2
About these Instructions..............................................4
For your Safety......................................................4
Where to Find the Controls..........................................7
Opening the Vitotronic 300-K.......................................7
Cascade Control Programming Unit ..............................7
Switching on the Heating System.................................9
Shutting Down the Heating System..............................9
Operating Program....................................................10
Time Program...........................................................11
Room Temperature....................................................13
Operating Program....................................................14
Time Program...........................................................14
Heating Curve..........................................................14
Stopping Central Heating...........................................15
Comfort Function “Comfort Mode”.............................15
Energy Saving Function “Economy Mode”....................16
Saving Function “Holiday Program”............................17
.
DHWTemperature.....................................................18
DHW Operating Program............................................18
DHW Time Program...................................................19
Stopping DHW Heating..............................................20
Setting the Boiler Sequence........................................21
Setting the Display Backlighting.................................21
Naming Heating Circuits............................................22
Setting the Time and Date.........................................22
Language Selection...................................................23
Setting Measuring Units.............................................23
Restoring the Factory Settings....................................23
Scanning Information.................................................24
Resetting Data.........................................................25
Scanning Service Messages........................................25
Scanning Fault Messages...........................................26
Emissions Test Mode................................................27
Rooms are Too Cold.................................................28
Rooms are Too Hot...................................................29
There is No DHW.....................................................29
The DHW is Too Hot.................................................29
“Fault” will be Displayed............................................30
“Service” will be Displayed.........................................30
Inspection and Maintenance.......................................30
Overview of Extended Menu......................................31
Scanning Options under “Information”........................32
Terminology............................................................33

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About these Instructions
For your Safety
Safety
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 loss of life, 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.
HOperation
Before operating the boiler, make sure you fully
understand its method of operation. Your heating
contractor should always perform the initial start-up
and explain the system. Any warranty is null and void
if these instructions are not followed.
HFlue gas smell
- Deactivate heating equipment.
- Open windows and doors.
- Inform your heating contractor.
HWorking on the equipment
All personnel working on the equipment or the heating
system must have the proper qualifications and hold
all necessary licenses. Ensure main power to
equipment, 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.
HDangerous conditions
- Deactivate main power immediately.
- Close gas supply valve.
HMaintenance and cleaning
Regular inspection and service by a qualified heating
contractor is important to the performance of the boiler.
Neglected maintenance impacts on warranty; regular
inspection ensures clean, environmentally friendly and
efficient operation. We recommend a maintenance
contract with a qualified heating contractor.
HTechnical Information
- Installation Instruction and Service Instructions
- Operating Instructions Vitotronic 300-K
- Operating Instructions Vitotronic 200
Additional applicable literature:
- Accessory manuals

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Vitotronic 300-K Operating
CAUTION
Should overheating occur or the gas supply fail to
shut off, do not disconnect the electrical supply to the
pump. Instead, shut off the gas supply at a location
external to the appliance.
WARNING
As there are no user-serviceable parts on the boiler,
burner or control, the end-user must not perform
service activities or adjustments of any kind on
system components. Failure to heed this warning can
cause property damage, severe personal injury, or loss
of life.
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
heating boiler, burners, 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.
CAUTION
Do not use this boiler if any part has been under water.
Immediately call a qualified heating contractor to inspect
the boiler and to replace any part of the control system
and any gas control which has been under water.
For your Safety (continued)
HCarbon 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.
HFor 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 is
recommended once a year. Maintenance, service and
cleaning are specified in the Installation Instructions.
Before the heating season begins, it is recommended that
the boiler and burner be serviced by a qualified heating
contractor. Service contracts may be established through
gas suppliers or other licensed contractors in your area.
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.
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.
Safety

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WARNING
Failure to protect against frozen pipes could result in
burst water pipes, serious property damage and/or
personal injury. Boiler may shut down. Do not leave
your home unattended for long periods of time during
freezing weather conditions without turning off the
water supply and draining water pipes or otherwise
protecting against the risk of frozen pipes.
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...
HShut off the water supply to the building, drain the
water pipes and add an antifreeze for potable water
to drain traps and toilet tanks. Open faucets where
appropriate.
Or..
HHave someone check the building frequently during cold
weather and call a qualified service agency if required.
Or...
HInstall a reliable remote temperature sensor that will
notify somebody of freezing conditions within the
home.
For your Safety (continued)
WARNING
Incorrect ambient conditions can lead to damage to
the heating system and put safe operation at risk.
IMPORTANT
Installation area conditions
HEnsure ambient temperatures are higher than 32°F
(0°C) and lower than 104°F (40°C).
HPrevent the air from becoming contaminated by
halogenated hydrocarbons (e.g. as contained in
paint 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.
HAvoid continuously high levels of humidity
(e.g. through frequent drying of laundry).
HNever 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.
Replacement components, spare and wear parts
Sources of combustion and ventilation air contaminants
Areas likely to contain contaminants:
HNew building construction
HSwimming pools
HRemodelling areas, hobby rooms
HGarages with workshops
HFurniture refinishing areas
HDry cleaning/laundry areas and establishments
HAuto body shops
HRefrigeration repair shops
HMetal fabrication plants
HPlastic manufacturing plants
HPhoto processing plants
HBeauty salons
Products containing contaminants:
HChlorine-type bleaches, detergents and cleaning
solvents found in household laundry rooms
HPaint and varnish removers
HHydrochloric acid, muriatic acid
HChlorine-based swimming pool chemicals
HSpray cans containing chlorofluorocarbons
HChlorinated waxes and cleaners
HCements and glues
HRefrigerant leaks
HCalcium chloride used for thawing
HSodium chloride used for water softening salt
HPermanent wave solutions
HAdhesives used to fasten building products and other
similar items
HAntistatic fabric softeners used in clothes dryers
Safety

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Vitotronic 300-K Operating Operation
Where to Find the Controls
Opening the Vitotronic 300-K
See the Remote Control Operating Instructions.
Each boiler is equipped with its own control unit.
These control units are regulated by a higher weather-
compensated cascade control unit.
HBoiler control unit:
Vitotronic 200
For use with multi boiler systems, the Vitotronic 200
is set up for operation with a constant boiler water
temperature.
As a result, display and settings on the Vitotronic 200
will only be accessible to a limited degree.
HHigher weather-compensated cascade control unit:
Vitotronic 300-K
You can change all settings for your heating system
centrally at the control unit programming units.
You may also make such changes at the remote control
units, if your system is equipped with such units.
Vitotronic 200
The programming unit is located behind cover flap A.
To open, pull the top edge of the hinged cover forward.
Cascade Control Programming Unit
A screensaver appears after opening the control unit,
or if there has not been any operation for some time.
The programming unit is equipped with a touchscreen.
To make adjustments and scan information, tap the
on-screen buttons.
Default display
In the default display, the number of boilers installed
in the heating system is shown in a specific order
(boiler sequence). You can change the boiler sequence
(see page 21).
Call up the default display as follows:
HScreensaver is active:
Tap the display anywhere, to begin.
HFrom anywhere in the menu tap .
Refer to the Vitotronic 300-K MW2C Installation
and Service Instructions.
Refer to applicable boiler Operating Instructions.

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Cascade Control Programming Unit (continued)
Operation
Legend
AHeader
BCommon supply temperature - Actual
CCommon supply temperature - Setpoint
DBoiler number (arranged in order of boiler sequence)
EDetails on the boiler operating mode
(see the following chapter)
FFooter
Boiler operating mode
The flame symbol indicates the approximate current boiler
heating output (in percent):
HFlame with glength
 1 to 33%
HFlame with hlength 34 to 66%
HFlame with full length 66 to 100%
Circle symbol:
HSolid white:
The boiler has been enabled by the cascade control unit
and is operating (boiler 1 and 2 in this example).
HSolid grey:
The boiler is available for generating heat but has not
been called for by the cascade control unit
(boiler 3 in this example).
HCrossed out:
The boiler has been disabled for heat generation
(boiler 4 and 5 in this example).
The value below the circle indicates the current output
(in MBH or kw based on the selected measuring units,
see page 23).
Main menu
In the main menu, you can change the boiler sequence
and scan and change all settings for functions made
available by the cascade control unit, such as heating
defaults and time programs.
You can find the menu structure overview on page 31.
Call up the main menu as follows:
HIf the screensaver is active:
Tap the display anywhere on the screen and then tap
“Menu”.
HFrom any menu level:
Tap and then tap “Menu”.
Footer buttons:
Returns you to the home screen.
Takes you back one menu level or cancels a setting
that has been started.
Calls up the help text.
 Calls up fault or service messages.
Scrolls through the menu if additional menu options
are available
Legend
AHeader
FFooter

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Vitotronic 300-K Operating Start-up/Shutdown
Switching on the Heating System
Legend
AON/OFF switch
BFuse
CON indicator (green)
DFault indicator (red)
E Emissions test switch
(only for service purposes)
1. Check the heating system pressure at the pressure
gauge (each boiler is equipped with a pressure gauge).
If the pressure of the heating system is too low,
top up the water or notify your heating contractor.
2. Open the gas shut-off valve on every boiler.
3. Switch ON the power supply, e.g. at a separate MCB/
fuse or a mains isolator.
4. Switch ON the ON/OFF switch on every control unit.
After a short delay, the home screen or the default
display appear.
The green ON indicator illuminates. Your heating
system and, if installed, your remote controls are now
ready for use.
Shutting Down the Heating System
Without frost protection monitoring (shutdown)
1. Switch OFF the ON/OFF switch on every control unit.
2. Close the gas shut-off valves.
3. Isolate the heating system from its main power supply,
e.g. at the separate MCB/fuse or at a mains isolator.
Note: If outdoor temperatures of below 37°F (3°C) are
expected, take appropriate measures to protect
the heating system from frost.
If necessary, contact your heating contractor.
Information on a prolonged shutdown
HCirculation pumps may seize up as they are not being
supplied with power.
HIt may be necessary to reset the date and time the next
time the system is switched on (see page 22).
With frost protection monitoring
For each heating circuit select the “standby mode”
operating program (see page 13).
HNo central heating
HNo DHW heating
HFrost protection for the boiler and the DHW tank
is active.
Pump exercise function
Circulation pumps are started for 10 sec. once every 24
hours to prevent the pumps from seizing up. This function
is active during all operating programs and during warm
weather shutdown.
Ask your heating contractor about the following:
HBoiler and relevant control unit type
HRequired system operating pressure
HLocation of the following components:
– Pressure gauge
– Gas shut-off valve
– Vents
Refer to the applicable boiler Operating
Instructions for gauge location and minimum
operating pressure.
Refer to the applicable boiler Operating Instructions

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Operating Program
Overview
Symbol Operating program Function
w
r“Heating and DHW” HThe rooms of the
selected heating
circuit are heated in
accordance with the
room temperature
and time program
specified (see chapter
“Central heating”).
HDHW is heated in
accordance with the
DHW temperature
and time program
specified (see chapter
“DHW heating”).
w“DHW only” HDHW is heated in
accordance with the
DHW temperature
and time program
specified (see chapter
“DHW heating”).
HNo central heating
HFrost protection for
the boiler and the
DHW tank is active.
9“Standby mode” HNo central heating
HNo DHW heating
HFrost protection for
the boiler and the DHW
tank is active.
Special operating programs
H“External hook-up”
The operating program set at the control unit was
changed by an external device, e.g. EA1 extension.
H“External program”
The operating program set at the control unit was
changed over by the Vitocom communication interface.
H“Holiday program”
The holiday program you have created is active.
See page 17.
Note: In the main menu, you can scan the set operating
program under “Information”.
The operating program for the heating system can be set
at the Vitotronic 300-K. There are 3 levels to the operating
program as described on the right.
Each heating circuit can be assigned it’s own operating
program (depending on the heating systems requirements).

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Vitotronic 300-K Operating Overview
Time Program
The following explains how to input the settings for a time
program. The special features of individual time programs
are allotted to the relevant chapters.
You can set up a time program for the following
functions:
HCentral heating - separate for each circuit
HDHW heating
HDHW recirculation pump
The time program allows you to divide the day into sections.
These are called time phases. It is for you to decide what
functions are active and the time period that function is
active, eg. whether the standard heating or the reduced
room temperature is active.
HYou can set the time program individually, to be the
same, or different, for every day of the week.
HYou can select up to 4 time phases per day.
HFor each time phase you select the start and end points.
HFor normal operation.
HIn the main menu, you can scan the time programs
under “Information” (see from page 32).
Setting a time program using central heating Heating
circuit 1 as an example
The settings described in the following apply equally for
DHW heating and the DHW recirculation pump.
Setting time phases
Example:
HTime program for “Monday”
HTime phase 1: 05:30 to 09:00 h
HTime phase 2: 16:30 to 22:00 h
Note: The time display is relative to the clock settings
12 h or 24 h (see page 22).
In between these time phases the system heats to a
reduced temperature (this temperature can be adjusted,
refer to page 13).
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”
4. “Time program heating”
5. “Mo”
6. “Change”
7. for the start and end point of time phase 1.
The bar in the time diagram is adjusted.
Cancelling the adjust/change to time phase early Tap .
8. ‘+’ to add an additional time phase.
9. for the start and end point of time phase 2.
The bar in the time diagram is adjusted.
10. Tap “OK” to confirm.
11. to return to the home screen or to return to
the main menu.

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Overview
Time Program (continued)
Copying a time program
You can copy a time program to other days of the week.
For example if, you want to copy this time program for
Monday to Tuesday to Friday.
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”
4. “Time program heating”
5. “Mo”
6. “Copy”
7. “Tu” , “We”, “Th”, “Fr”
8. Tap “OK” to confirm
9. to return to the home screen or to return to
the main menu.
Changing time phases
For Tuesday you want to change the start point of time
phase 2 to 14:30 h.
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”
4. “Time program heating”
5. “Tu”
6. “Change”
7. for time phase 2
8. for the start point of time phase 2 on.
The bar in the time diagram is adjusted.
9. Tap “OK” to confirm
10. to return to the home screen or to return to
the main menu.
Deleting time phases
For Wednesday you want to delete time phase 2.
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”
4. “Time program heating”
5. “We”
6. “Change”
7. for time phase 2
8. “x”
9. Tap “OK” to confirm
10. to return to the home screen or to return to
the main menu.

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Vitotronic 300-K Operating Central Heating
Note: Further information can be found in chapter
“Terminology” in the appendix.
Setting standard room temperature for the selected
heating circuit
Factory setting: 68°F (20°C)
Setting range: 37 to 99°F (3 to 37°C)
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “ Room temp set point”
5. for the desired value
6. Tap “OK” to confirm
Setting the reduced room temperature
Factory setting: 64°F (18°C)
Setting range: 37 to 99°F (3 to 37°C)
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Reduced room temp set point”
5. for the desired value
6. Tap “OK” to confirm
Central heating with this temperature, will occur
HBetween the time phases for central heating with
standard temperature
HDuring a holiday program (see page 16)
Room Temperature
Operating Program
Note: Further information can be found in chapter
“Terminology” in the appendix.
Setting the operating program
Factory setting: “Heating and DHW”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Operating program”
5. Tap “OK” to confirm
Note: For information on the operating programs, see page 17
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14
Central Heating
Heating Curve
Note: Further information can be found in chapter
“Terminology” in the appendix.
Setting the heating curve
Factory setting:
H“Slope”: 1.4
H“Shift” of the heating curve: 0
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Heating curve”
5. for the desired value for “Slope” and/or “Shift”
6. Tap “OK” to confirm
Example: Changing the heating curve slope to 1.5
A graph clearly shows the change in the heating curve
as soon as you alter the value for the slope or shift.
Depending on various outdoor temperatures (shown on
the horizontal axis), the assigned set supply temperatures
for the heating circuit are highlighted in white.
Time Program
Note: Further information can be found in chapter
“Terminology” in the appendix.
Setting the time program for central heating
Factory setting: One time phase from 00:00 to 24:00 h
for every day of the week
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Time program heating”
5. Tap “OK” to confirm
Procedure for setting a time program, see page 11
Note: When adjusting the setting, bear in mind that your
heating system requires some time to heat the
rooms to the required temperature.

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Vitotronic 300-K Operating Central Heating
Comfort Function “Comfort Mode”
Setting “Comfort mode”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Comfort mode”
5. “Comfort”
6. Tap OK to confirm
7. for the required set room temperature in comfort
mode
8. Tap “OK” to confirm
HThe rooms are heated to the set room temperature.
HProvided your heating contractor has not altered the
settings, DHW is heated to the set temperature first,
before central heating begins.
HThe DHW recirculation pump is switched on (if installed).
Ending “Comfort mode”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Comfort mode”
5. “Comfort” The white frame is reset.
6. Tap “OK” to confirm
or
Automatically when the system switches to standard
heating mode in accordance with the time program
or
Automatically after 8 hours
Note: If you want to make changes to this, contact your
local heating contractor.
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Operating program”
5. “DHW only” (no central heating)
or
“Standby mode” (frost protection for the boiler and the
DHW tank is active)
6. Tap “OK” to confirm
Note: This process must be repeated for each heating
circuit connected to the Vitotronic 300-K.
Stopping Central Heating

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16
Central Heating
Energy Saving Function “Economy Mode”
Setting “Economy mode”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Economy mode”
5. “Eco”
6. Tap “OK” to confirm
Note: You can only enable this energy saving function
when the heating system is in the standard heating
mode.
Ending “Economy mode”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the,required heating circuit
4. “Economy mode”
5. “Eco” The white frame is reset.
6. Tap “OK” to confirm
or
Automatically when the system switches to reduced
heating mode in accordance with the time program

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Vitotronic 300-K Operating Central Heating/DHW Heating
Energy Saving Function “Holiday Program”
The holiday program has the following effect:
HCentral heating:
– For heating circuits with the operating program
“Heating and DHW”:
The rooms are heated to the set reduced room
temperature (see page 13).
– For heating circuits in the operating program “DHW only”:
No central heating. Frost protection for the boiler and
the DHW tank is active.
HDHW heating:
No DHW heating. Frost protection for the DHW tank
is active.
Cancelling or deleting the “Holiday program”
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Holiday program”
5. for “Return date” the same date as for the
“Departure date”
6. Tap “OK” to confirm
Setting “Holiday program”
Note: The holiday program affects all heating
circuits. If you want to make changes to this,
contact your local heating contractor.
The holiday program starts at 00:00 h (12:00 am) the
day after the departure date. The holiday program ends
at 00:00 h (12:00 am) on the return date. This means
that the standard time program is active on the days of
departure and return.
From the home screen tap the following buttons:
1. “Menu”
2. “Heating”
3. “Heating circuit 1”, “Heating circuit 2” or “Heating
circuit 3” as the required heating circuit
4. “Holiday program”
5. for “Departure date” and “Return date”
6. Tap “OK” to confirm

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18
DHW Temperature
Factory setting: 122°F (50°C)
Setting range: 80 to 140°F (10 to 60°C)
From the home screen tap the following buttons:
1. “Menu”
2. “DHW”
3. “DHW temperature”
4. for the required value
5. Tap “OK” to confirm
DHW Operating Program
Note: Further information can be found in chapter
“Terminology” in the appendix.
Setting the operating program for DHW heating
Factory setting: “Heating and DHW” If no central heating
is required, set “DHW only”.
For information on the operating programs, see page 10.
DHW Heating

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Vitotronic 300-K Operating DHW Heating
DHW Time Program
Note: Further information can be found in chapter
“Terminology” in this manual.
Setting the time program for DHW heating
Factory setting: “Automatic”
During operation with standard room temperature, DHW
in the DHW tank is heated to the set DHW temperature.
The time phase for DHW heating automatically starts half
an hour earlier than the time phase for central heating
with standard room temperature. DHW heating may
start, for example, at 05:30 h if the start time for central
heating is 06:00 h. This means hot water is already
available when your system starts operating with standard
room temperature.
You can change this time program individually
in accordance with your requirements.
From the home screen tap the following buttons:
1. “Menu”
2. “DHW”
3. “Time program DHW”
4. “Individual”
5. Tap “OK” to confirm
For how to set a time program, see page 11.
Note: - The DHW is not heated between the time phases.
Frost protection for the DHW tank is active.
- When setting time programs, bear in mind that
your heating system requires some time to heat
the DHW tank to the desired temperature.
DHW fourth phase heating (auxiliary function)
This function can be used to heat the water in the DHW
tank to a higher set DHW temperature.
Your heating contractor can enable this function by
specifying a second set DHW temperature.
Set time phase 4 for this. During this time, DHW will
be heated to the second set DHW temperature value.
Note: A start and stop time must be set for the 2nd and
3rd time phase.

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20
DHW Heating
Time Program (continued)
DHW heating once, outside the time program
Note: The operating program “Heating and DHW” or
“DHW only” must be set for at least one system
heating circuit.
Enable “Comfort mode” (see page 26) and
immediately disable it again. This prevents
unintentional central heating with standard room
temperature.
Setting the time program for the DHW recirculation pump
Factory setting: “Automatic”
The DHW recirculation pump operates in parallel to the
DHW heating time program. You can change this time
program individually in accordance with your requirements.
From the home screen tap the following buttons:
1. “Menu”
2. “DHW”
3. “DHW recirculation time program”
4. “Individual”
5. Tap “OK” to confirm
For how to set a time program, see page 11.
Note: Between the time phases the DHW recirculation
pump remains off.
Stopping DHW Heating
If you would like to terminate or prevent DHW heating
during standard operating mode, reduce the DHW
temperature setpoint to 50°F (10°C).
From the home screen tap the following buttons:
1. “Menu”
2. “DHW”
3. “DHW temperature”
4. for 50°F (10°C)
5. Tap “OK” to confirm