Buderus Logano plus GB402 User manual

For users
Read carefully before use.
Operating instructions Gas condensing boiler
Logano plus GB402
6 720 642 928 (07/2009) GB

Introduction
Logano plus GB402 - Subject to technical modifications.
2
Introduction
Dear Customer,
Heat is our element – and has been now for more than
275 years. Right from the start, we invest all our energies
and passion into developing individual solutions for you,
so you feel comfortable in your home.
Whether heat, domestic hot water or ventilation, a
product from Buderus will always provide you with highly
efficient heating technology of proven quality that will
reliably keep your home cosy for many years to come.
We manufacture in accordance with the state of the art
and ensure that our products are efficiently matched to
each other. In this endeavour, efficiency and
environmental compatibility are our priorities.
Thank you for choosing a Buderus product – a choice that
will give you not only efficient energy utilisation but also
high levels of comfort and convenience. To ensure that
you retain this level of excellence, please read the
operating instructions carefully. If, contrary to
expectations, problems arise, please contact your installer
who will be happy to assist you.
Should your installer not be available, then contact our
customer service that is available to you around the clock.
We hope you will enjoy your new Buderus product!
Your Buderus Team

Contents
Logano plus GB402 - Subject to technical modifications. 3
Contents
1 Explanation of symbols
and safety information . . . . . . . . . . . . . . . . . . . 4
1.1 Explanation of symbols . . . . . . . . . . . . . . . . . 4
1.2 Safety precautions . . . . . . . . . . . . . . . . . . . . . 4
2 Product information . . . . . . . . . . . . . . . . . . . . . 6
2.1 EU Declaration of Conformity . . . . . . . . . . . . 6
2.2 Intended use . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.3 Water quality (fill and top-up water) . . . . . . . 6
2.4 Disposal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.5 Product description . . . . . . . . . . . . . . . . . . . . 7
3 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 User interface elements . . . . . . . . . . . . . . . . . 8
3.2 Setting temperatures . . . . . . . . . . . . . . . . . . . 9
3.2.1 Specifying the set DHW temperature . . . . . 9
3.2.2 Setting the boiler water temperature . . . . . 10
3.3 Showing values on the display . . . . . . . . . . 11
3.4 Manual mode (emergency mode) . . . . . . . . 11
3.5 Setting pump run-on time . . . . . . . . . . . . . . 12
4 Operating the heating system . . . . . . . . . . . . 13
4.1 Switching on the heating system . . . . . . . . 13
4.1.1 Starting the heating system
using the base controller (BC10)
and the programming unit (RCxx) . . . . . . . 13
4.2 Shutting down the heating system . . . . . . . 14
4.2.1 Shutting down the heating system
via the control unit . . . . . . . . . . . . . . . . . . . . 14
4.2.2 Shutting down the heating system
in emergencies . . . . . . . . . . . . . . . . . . . . . . 14
4.3 Checking the operating pressure,
topping up the heating water and
venting the system . . . . . . . . . . . . . . . . . . . 14
4.3.1 Checking the operating pressure . . . . . . . . 14
4.3.2 Topping up the heating water
and venting the system . . . . . . . . . . . . . . . . 15
5 Inspection and maintenance . . . . . . . . . . . . . 16
5.1 What makes regular maintenance
important? . . . . . . . . . . . . . . . . . . . . . . . . . . 16
5.2 Cleaning and care . . . . . . . . . . . . . . . . . . . . 16
6 Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . 17
6.1 Recognising the operating state
and resetting faults . . . . . . . . . . . . . . . . . . . 17
Guide to instructions
Installation and maintenance should only be carried out by
qualified contractors authorised by Buderus.
BPrior to commencing operation, carefully read the
whole of these Logano plus operating instructions.
BKeep this manual safe for future reference.

1Explanation of symbols and safety information
Logano plus GB402 - Subject to technical modifications.
4
1 Explanation of symbols and safety information
1.1 Explanation of symbols
Warning symbols
Signal words indicate the seriousness of the hazard in
terms of the consequences of not following the safety
instructions.
•NOTICE indicates possible damage to property or
equipment, but where there is no risk of injury.
•CAUTION indicates possible injury.
•WARNING indicates possible severe injury.
•DANGER indicates possible risk to life.
Important information
Additional symbols
1.2 Safety precautions
If you smell gas
BClose the gas tap.
BOpen windows and doors.
BDo not operate electrical switches, including
telephones, plugs or doorbells.
BExtinguish all naked flames. Do not smoke! Do not use
lighters.
BWarn all occupants of the building, but do not ring
doorbells.
BIf you can actually hear gas escaping, leave the building
immediately. Prevent others from entering and notify
the police and fire services from outside the building.
BFrom outside the building, call your gas supply
utility and approved contractor.
If you smell flue gas
BSwitch off the boiler (Æpage 14).
BOpen windows and doors.
BNotify an authorised contractor.
Installation, conversion
BCorrect and proper installation and adjustment of the
burner and the control unit are the fundamental
requirements for safe and economical operation of the
boiler.
BThe boiler may only be installed or converted by an
approved heating contractor.
BNever change any parts in contact with flue gas.
BDo not cover or reduce the size of ventilation apertures
in doors, windows and walls. If draught-proof windows
are fitted, ensure there is an adequate supply of
combustion air.
BThe DHW cylinder may only be used for heating
domestic hot water.
BNever shut off safety valves! Water is expelled from
the heating circuit and DHW circuit safety valve during
heat-up.
Safety instructions in this document are
framed and identified by a warning triangle
which is printed on a grey background.
Electrical hazards are identified by a lightning
symbol surrounded by a warning triangle.
Notes contain important information in cases
where there is no risk of personal injury or
material losses and are identified by the
symbol shown on the left. They are bordered
by horizontal lines above and below the text.
Symbol Meaning
Ba step in an action sequence
Æa reference to a related part in the
document or to other related documents
• a list entry
–a list entry (second level)
Tab. 1

1
Explanation of symbols and safety information
Logano plus GB402 - Subject to technical modifications. 5
Inspection/maintenance
BRecommendation for customers: Arrange a
maintenance and inspection contract with an
authorised contractor, covering an annual inspection
and demand-dependent maintenance.
BMaintenance and repairs may only be carried out by an
approved heating contractor.
BHave any faults immediately rectified in order to prevent
damage to the system.
BThe operator is responsible for the general and
environmental safety of the heating system.
BUse original spare parts only. Damage caused by the
use of parts not supplied by Buderus is not covered by
the Buderus warranty.
Danger through failure to consider your own safety
in an emergency such as a fire
BNever put yourself at risk of fatal injury. Your own safety
is paramount.
Dangers posed by explosive and easily flammable
materials
BAny work on components in contact with gas may only
be carried out by an approved contractor.
BNever use or store easily flammable materials (paper,
thinners, paints etc.) near the boiler.
Risk of poisoning. An insufficient supply of air can
result in dangerous escape of flue gas
BNever block ventilation and extract air apertures or
reduce their size.
BThe boiler must not be operated, unless you
immediately remedy the fault.
Risk of water damage
BIn the event of severe risk of flooding, disconnect the
appliance from its power supply and shut off the fuel
supply before water enters the installation room.
BNever use the appliance if any part of it has been under
water.
BImmediately call a qualified service technician to
inspect the appliance and to replace any part of the
control system and any gas valves that have been
under water.
Combustion air
BKeep the combustion air free of corrosive substances
(e.g. halogenated hydrocarbons that contain chlorine
or fluorine compounds). This will help prevent
corrosion.
BAvoid very dusty atmospheres.
Instructing the customer
BThe operator must read the information on how the
boiler works and have the heating system installer
(approved contractor) explain how to operate it.
Further important information
BNever switch off or interrupt the power supply to the
pump in case of overheating or if the gas supply does
not shut down. Instead, interrupt the gas supply at
another point outside the heating system.
BThe flue system must be checked annually. During this
inspection, have a contractor replace any parts that
show signs of damage through corrosion or other
causes.
BThe boiler must be serviced annually by a qualified
service provider. The inspection must include the main
burner, the entire flue gas and ventilation air system as
well as the air inlet apertures or vents. During this
inspection, have a contractor replace any parts that
show signs of damage through corrosion or other
causes.
Risk of damage due to operator error
Operator errors can result in injury and damage to
property.
BEnsure that children never operate this appliance
unsupervised or play with it.
BEnsure that only personnel who can operate this
appliance correctly have access to it.

2Product information
Logano plus GB402 - Subject to technical modifications.
6
2 Product information
To ensure safe, economical and environmentally
responsible use of the heating system, we recommend
that you read the safety instructions and operating
instructions carefully.
These instructions provide the operator of the heating
system with an overview of the use and operation of the
boiler.
2.1 EU Declaration of Conformity
The design and operation of this product conform to
the European Directives and the supplementary national
requirements. Its conformity is demonstrated by the
CE designation. You can call up the Declaration of
Conformity for this product on the internet at
www.buderus.de/konfo or request a copy from your
local Buderus sales office.
2.2 Intended use
The Logano plus GB402 is designed for conventional use
as a gas condensing boiler for DHW and central heating.
The boiler can be equipped with a programming unit,
e.g. RC35 (available separately).
2.3 Water quality (fill and top-up water)
For information regarding the water quality, see the
enclosed operator's log “Water quality requirements for
heat sources made from aluminium”.
2.4 Disposal
BDispose of boiler packaging in an environmentally
responsible manner.
BAll heating system components that have to be
replaced should be disposed of in an environmentally
responsible manner at an authorised disposal site.

2
Product information
Logano plus GB402 - Subject to technical modifications. 7
2.5 Product description
The Logano plus GB402 (ÆFig. 1) is a gas condensing
boiler with an aluminium heat exchanger.
Fig. 1 Logano plus GB402 - main components
1Boiler front panel
2Gas valve
3Control unit (MC10 and BC10)
4Gas burner (burner rod)
5Boiler block with thermal insulation
6Boiler casing
7Condensate tray and siphon
8Burner control unit
The main components of the Logano plus GB402
(ÆFig. 1) are:
• Control unit
• Appliance frame and casing
• Boiler block with thermal insulation
• Gas burner
The control unit monitors and controls all electrical boiler
components.
The boiler block transfers the heat generated by the
burner to the heating water. The thermal insulation
reduces the radiation and standby losses.

3Operation
Logano plus GB402 - Subject to technical modifications.
8
3Operation
3.1 User interface elements
The base controller (BC10) is located behind the control
unit fascia and enables standard operation of the heating
system or the Logano plus GB402 boiler.
BTo access the user interface of the base controller, flip
up the control unit fascia.
Fig. 2 Controls on the BC10 base controller
1ON/OFF switch
2Rotary selector for set DHW temperature
3“DHW heating” LED
4Status display
5Rotary selector for maximum boiler water temperature
6“Heat demand” LED
7Slot cover for programming unit RCxx
8“Burner” (ON/OFF) LED
9Connection socket for diagnostic plug
10 “Status display” key
11 “Emissions test” key for flue gas test and manual mode
12 “Reset” key
ON/OFF switch
Start and shut down the boiler using ON/OFF switch [1].
“Reset” key
If the system has developed a fault, restart the boiler by
using the “Reset” key [12].
This is only required with disabling faults (display flashes).
Blocking faults are reset automatically when the cause is
removed. The display shows “ρΕ” whilst the reset is being
implemented.
d“emissions test” key
The boiler can be put in manual mode via the dkey [11],
for example if the heating system control unit
(e.g. programming unit) is faulty (ÆTab. 5, page 11).
e“status display” key
The ekey [10] enables the current boiler water
temperature, the current operating pressure etc. to be
displayed (ÆTab. 3.3, page 11).
Connection options for diagnostic plug
Here, the service engineer can connect a diagnostic plug
(service tool) [9].
“Burner” (ON/OFF) LED
The “burner” LED (ON/OFF) [8] signals the burner
operating condition.This LED illuminates when the burner
is in operation and the boiler water is being heated up.
The LED stays off when the boiler water is within the
required temperature range or when there is no heat
demand.
“Heat demand” LED
The “heat demand” LED [6] illuminates if the control unit
generates a heat demand (e.g. if rooms that require
heating become too cold).
Rotary selector for maximum boiler water
temperature
Select the upper temperature limit for the boiler water with
the maximum boiler water temperature rotary selector [5]
(ÆChapter 3.2.2). The unit is °C.
Display
Check the status and values of the heating system on the
display [4]. Faults are immediately indicated by the display
in the form of a fault code, as soon as they develop.
Locking faults cause the status display to flash.
Rotary selector for set DHW temperature
The rotary selector for the set DHW temperature [2]
specifies the required DHW temperature
(ÆChapter 3.2.1). The unit is °C.
“DHW heating” LED
The “DHW heating” LED [3] illuminates if a heat demand
has been generated for DHW (e.g. if hot water is
required).
In a heating system with several boilers
(cascade system), settings must be made at
the control unit of every boiler.
6 720 617 694-01.1RS
1
2 3 4 5 6
12 11 10 9 8 7
If, after resetting the burner, a fault condition
recurs, see Chapter 6. If necessary, ask the
authorised contractor to remedy the fault.

3
Operation
Logano plus GB402 - Subject to technical modifications. 9
3.2 Setting temperatures
3.2.1 Specifying the set DHW temperature
BWith the set DHW temperature rotary selector [1]
select the required DHW cylinder temperature.
Fig. 3 Set DHW temperature rotary selector
The LED [2] below the rotary selector
illuminates if DHW is being reheated or the
DHW temperature is still below the required
temperature (heat demand).
6 720 617 694-04.1RS
1
2
Status Explanation LED
0Off No DHW provision (only central heating). Off
Eco Economy mode1),
DHW temperature 60 °C
DHW is only heated to 60 °C again if the temperature
has dropped significantly. This reduces the number of
burner starts and saves energy. However, the water may
be somewhat cooler in the first few moments.
ON 2)
30 – 60 Direct setting at the BC101)
in °C
The temperature is set at the BC10 and can then no
longer be adjusted with the programming unit.
ON 2)
Aut Specified via the programming unit1)
(preset)
The temperature is set at the programming unit (RCxx).
If no programming unit is connected, 60 °C is the
maximum DHW temperature.
ON 2)
Tab. 2 Setting options on the rotary selector for set DHW temperature
1) The heating program (time switch) on the room controller remains active so that DHW is not heated during night mode.
2) The LED below the rotary selector illuminates if DHW is being reheated or the DHW temperature is below the required temperature
(heat demand).

3Operation
Logano plus GB402 - Subject to technical modifications.
10
3.2.2 Setting the boiler water temperature
BSelect the upper temperature limit for the boiler water
in heating mode with the maximum boiler water
temperature rotary selector [1] according to Tab. 3.
Fig. 4 Base controller user interface
1Rotary selector for maximum boiler water temperature
NOTICE: System damage in underfloor
heating systems through overheating the
pipework!
BFor underfloor heating systems, never set
the boiler water temperature higher than
40 °C.
To save energy, set the maximum boiler water
temperature low enough that it is still
sufficiently warm inside the building.
The required room temperature cannot be
achieved if this temperature is set too low.
For further details regarding energy saving,
see the programming unit or control unit
operating instructions.
6 720 617 694-05.1RS
1
Controller position Setting for Explanation
0 Heating operation is switched OFF (poss. only DHW operation).
40 Underfloor heating system
Required boiler water temperature in °C
75 – 90 Radiators
90 Convector heaters
Aut Underfloor heating
Radiators
Convector heaters
The temperature is established automatically with a programming
unit RCxx using the heating curve. If no programming unit is
connected, the maximum boiler water temperature is 90 °C.
Tab. 3 Settings at the maximum boiler water temperature rotary selector

3
Operation
Logano plus GB402 - Subject to technical modifications. 11
3.3 Showing values on the display
Information about the operating state of the boiler can be
called up on the display with the ekey [1]. The currently
recorded values are displayed:
• Boiler water temperature (permanent display)
• Operating pressure
• Operating code
Fig. 5 BC10 base controller
1“Status display” key
3.4 Manual mode (emergency mode)
In manual mode, the heating system can operate
independent of a programming unit (RCxx) (emergency
mode if the programming unit has developed a fault).
The boiler will operate with the boiler water temperature
selected on the maximum boiler water temperature rotary
selector as the set temperature. Only operate the heating
system briefly in manual mode.
6 720 617 694-02.1RS
1
Status display
Step Display
[\/2/4| Currently recorded flow temperature in °C.
e[p/1.6| Currently recorded operating pressure in bar.
e[-/h/\| Operating code (here: boiler in heating mode).
eor wait 5 minutes [\/2/4| Back to the menu: currently recorded flow temperature.
Tab. 4 Checking information regarding the operating state
NOTICE: System damage due to frost!
The heating system can freeze up as a
result of a power failure or if the power
supply has been switched off.
BReactivate manual mode after switching
on to keep the heating system
operational (particularly when there is a
risk of frost).
Switching the manual mode menu ON/OFF
Step Display
[\/2/4| Currently recorded flow temperature in °C.
d
> 5 seconds [/2/4} Activating manual mode: hold down key dfor longer than 5 seconds.
Manual mode becomes active as soon as a flashing dot appears in the bottom
r.h. corner of the display.
d
> 2 seconds [\/2/4| Terminating manual mode
(manual mode also terminates after the power supply has been interrupted).
Tab. 5 Manual mode (emergency mode)

3Operation
Logano plus GB402 - Subject to technical modifications.
12
3.5 Setting pump run-on time
The standard setting for the pump run-on time is suitable
for most situations.
Exception for room temperature-dependent
control: If there is a risk of frost for the components of
the heating system that are located outside the range
of influence of the room temperature controller
(e.g. radiators in the garage), the pump run-on time must
be set to 24 hours (ÆTab. 6).
The pump is automatically switched on
permanently in case of weather-
compensated control and temperatures
below 3 °C.
Settings menu
Step Display
[\/2/4| Currently recorded flow temperature in °C (display in standard mode).
ee
(twice) [\/f/5| Pump run-on time in minutesHold down dfor [f/d1| (24 hours)
Hold down cuntil the required pump run-on time is shown
(at least [f//0| = 15 seconds)
ee(twice)
or wait 5 minutes [\/2/4| Back to standard operation.
Tab. 6 Pump run-on time

4
Operating the heating system
Logano plus GB402 - Subject to technical modifications. 13
4 Operating the heating system
4.1 Switching on the heating system
Before switching the system on, check that:
• the operating pressure is high enough,
• the fuel supply has been turned on at the main shut-off
valve, and
• the heating system emergency stop switch is switched
on.
4.1.1 Starting the heating system using the base
controller (BC10) and the programming unit
(RCxx)
BSet both rotary selectors on the control unit to “AUT”
(automatic mode). The programming unit (RCxx) takes
control in this setting.
Fig. 6 Rotary selectors set to “AUT”
BSet the ON/OFF switch on the base controller to
position “1”.
The control unit checks the current system status, and
the burner may start.
If the boiler recognises a heat demand, the start program
commences and approx. 30 seconds later the burner fires
up. A heat demand is triggered if the heating or the DHW
temperatures fall below their respective set values. The
LED below the relevant rotary selector illuminates.
Fig. 7 Switching on the heating system
At the programming unit (RCxx), we would recommend
you check or adjust the following:
• Automatic operating mode
• Required room temperature
• Required DHW temperature
• Required heating program
Fig. 8 Programming unit (e.g. RC35, with open flap)
6 720 618 585-60.1RS
6720614021-041.1TD
The programming unit (RCxx) operating
instructions detail how to make these
adjustments and the benefit they will bring.
BPlease read and follow the programming
unit (RCxx) operating instructions.
7 747 010 718-04.1RS

4Operating the heating system
Logano plus GB402 - Subject to technical modifications.
14
4.2 Shutting down the heating system
4.2.1 Shutting down the heating system via the
control unit
Shut down the heating system via Logamatic BC10 base
controller. Switching off the Logamatic BC10 base
controller also automatically shuts down the burner.
BShut down the heating system at the ON/OFF switch
of the BC10 (position “0”).
BClose the main fuel shut-off valve.
Fig. 9 Logamatic BC10 basic controller
4.2.2 Shutting down the heating system in
emergencies
Explain to the customer what to do in an emergency,
e.g. a fire.
BNever risk your own life. Your own safety is paramount.
BClose the main fuel shut-off valve.
BIsolate the heating system from the mains power
supply by means of the heating system emergency
stop switch or the appropriate domestic fuse/circuit
breaker.
4.3 Checking the operating pressure,
topping up the heating water and
venting the system
The water with which the heating system is first filled
decreases substantially in volume in the first few days due
to the release of gas. This causes air pockets to form and
the heating water starts to make noises.
BWith new heating systems, check the operating
pressure daily at first, topping up the heating water and
bleeding the radiators if required.
BLater on, check the operating pressure monthly,
topping up heating water and venting the boiler and
radiators if needed.
4.3.1 Checking the operating pressure
Your heating contractor will have set the red needle of
pressure gauge [1] to the required operating pressure
(at least 1 bar) and will have recorded this value in tab. 7,
page 15.
BCheck that pressure gauge needle [2] is inside the
green band [3].
BIf the pressure gauge needle drops below the green
band, top up the heating water.
Fig. 10 Pressure gauge for sealed unvented systems
1Red needle
2Manometer needle
3Green band
NOTICE: System damage due to frost!
When the heating system is switched off, the
system water can freeze up.
BIn case of a risk from frost, protect the
heating system against frost damage. To
do so, drain the heating water at the
lowest point of the heating system. Do this
by opening the air vent valve at the highest
point in the heating system.
Only in emergencies, switch off the heating
system via the installation room fuse/circuit
breaker or the heating system emergency
stop switch.
6 720 615 876-59.1RS
3
2
1

4
Operating the heating system
Logano plus GB402 - Subject to technical modifications. 15
4.3.2 Topping up the heating water and venting the system
Ask your heating contractor to show you where, outside
the boiler itself, the boiler drain & fill valve for topping up
the heating water is located in your heating system.
BConnect hose to the water tap. Push the water-filled
hose onto the hose ferrule of the boiler fill & drain valve,
fasten with a hose clip and open the valve.
BSlowly fill the heating system. Observe the pressure
gauge whilst filling.
BClose the water tap and boiler drain & fill valve once the
required operating pressure has been reached.
BVent the heating system via the radiator bleed valves.
BTop up with water if the operating pressure has fallen
as a result of the venting process (see setting for red
needle on the pressure gauge ÆFig. 10, page 14).
BRemove the hose from the boiler fill & drain valve.
CAUTION: Health risk from contaminated
drinking water!
BObserve all national standards and
regulations regarding prevention of
domestic water contamination (e.g. by
water from heating systems).
BIn Europe, observe standard EN 1717.
NOTICE: System damage due to
temperature fluctuations!
Temperature stresses can cause cracks if
you fill your heating system when it is hot.
The boiler will then leak.
BOnly fill the heating system when cold
(the flow temperature should not exceed
40 °C).
NOTICE: System damage due to frequent
topping up!
If you have to top up the heating water
frequently, the heating system may suffer
damage from corrosion or scaling,
depending on the water quality.
BAsk your heating contractor if the local
water can be used untreated or whether it
needs to be treated.
BShould the fill/top-up water need
treatment, let your heating contractor top
up your heating system.
BObserve the water quality specified in
the operator's log “Water quality
requirements for heat sources made from
aluminium”. Enter the amount of top-up
water into the operator's log, as the
heating contractor has shown you.
BNotify your heating contractor if you find
you need to top up your heating system
frequently.
Operating pressure
Set operating pressure
(optimum value) _____________ bar
Tab. 7 Operating pressure (entered by the heating
contractor)

5Inspection and maintenance
Logano plus GB402 - Subject to technical modifications.
16
5 Inspection and maintenance
5.1 What makes regular maintenance
important?
Heating systems should be regularly serviced for the
following reasons:
• to maintain a high level of efficiency and to operate the
system economically (low fuel consumption),
• to achieve a high level of operational reliability,
• to maintain the cleanest possible combustion.
5.2 Cleaning and care
To clean the boiler, wipe the casing with a damp cloth
(soapy solution). Never use scouring or aggressive
cleaning agents that would damage the painted surface
or plastic components.
NOTICE: System damage through absence
of or inadequate cleaning and maintenance!
BHave your heating system inspected,
cleaned and serviced annually by a
contractor.
BWe recommend you enter a contract
covering an annual inspection and service
subject to demand.

6
Troubleshooting
Logano plus GB402 - Subject to technical modifications. 17
6 Troubleshooting
6.1 Recognising the operating state and
resetting faults
If a fault has developed, the fault code flashes on the
control unit display. The programming unit shows faults as
plain text messages.
A fault has developed if the display flashes and indicates
something other than the current boiler water temperature
or an operating message.
Example: “6A” = the burner will not start
BHold down “Reset” for 5 seconds to clear the fault.
The display shows “rE” whilst the system is being reset.
The reset is only possible if a fault message is flashing.
If the display then reverts to a standard operating
message, the fault has been eliminated. Should the fault
recur, repeat the reset two or three times.
Fig. 11 Clearing a fault with the “Reset” key
If a fault cannot be reset:
BNote down the fault message and notify a heating
contractor.
For more information on possible faults, see the
installation and maintenance instructions as well as the
control unit documentation.
NOTICE: System damage due to frost!
The heating system can freeze up if it has
been switched off through a fault
shutdown.
BRectify the fault immediately and
restart the heating system.
BWhere that is not possible, protect the
heating system against frost by
draining the heating and DHW
pipework at the lowest point.

6
Logano plus GB402 - Subject to technical modifications.
18
Notes

6
Logano plus GB402 - Subject to technical modifications. 19
Notes

Buderus
Cotswold Way, Warndon, Worcester WR4 9SW
Customer service: 0844 892 3004
echnical support: 0844 892 4224
Fax: [phone]
www.buderus.co.uk
In the UK and IE, Buderus is a brand name of
Bosch hermotechnology Ltd.