Buderus Logamax plus User manual

Only for authorized service
technician !
Service Manual Gas Wallhung Boiler
Logamax plus
6 720 641 705-00.1O
GB012 - 25K
2011/10 EN - U. Demir

Content
GB012 - 25K
2
Content
1 Safety precautions and symbols . . . . . . . . . . . . . . . 3
1.1 Symbols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.2 Safety precautions . . . . . . . . . . . . . . . . . . . . . 3
2 Service Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1 Display Symbols . . . . . . . . . . . . . . . . . . . . . . . 4
2.2 Service Function . . . . . . . . . . . . . . . . . . . . . . 4
2.3 Service Function Overview . . . . . . . . . . . . . . 5
2.3.1 1. Service Level . . . . . . . . . . . . . . . . . . . . . . . 5
2.3.2 2. Service Level . . . . . . . . . . . . . . . . . . . . . . . 6
3 Failures / Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
3.1 Elimination of errrors . . . . . . . . . . . . . . . . . . . 7
3.2 Failure / Error Codes Overview . . . . . . . . . . . 8
3.3 Failure codes and corrections steps . . . . . . . 9
3.4 Sensor (NTC) Values . . . . . . . . . . . . . . . . . . 25
3.4.1 Flow Temperature Sensor . . . . . . . . . . . . . . 25
3.4.2 Domestic Hot Water Temperature Sensor . . 25
3.4.3 Flue Gas Safety Temperature Sensor (Behind
Burner) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.5 Electrical Datas . . . . . . . . . . . . . . . . . . . . . . 26
3.6 Electrical Circuit Diagram . . . . . . . . . . . . . . . 27
3.7 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
3.8 Function Diagram . . . . . . . . . . . . . . . . . . . . . 31
4 Gas Values (Cental heating and domestic
hot water circuit) 32

1
Safety precautions and symbols
GB012 - 25K 3
1 Safety precautions and symbols
1.1 Symbols
Signal words indicate the seriousness of the hazard in terms
of the consequences of not following the safety instructions.
•Caution indicates that minor damage to property could
result.
•Warning indicates that minor personal injury or serious
damage to property could result.
•Danger indicates that serious personal injury could result.
In particularly serious cases, lives could be at risk.
Notes contain important information in cases where there is
no risk of personal injury or damage to property.
1.2 Safety precautions
If you smell gas
BTurn off gas service cook.
BOpen windows.
BDo not operate any electrical switches.
BExtinguish any naked flames.
BLeave the building and telephone the gas company and
authorized dealer from an outside phone.
If you smell fumes from the appliance
BSwitch off the appliance.
BOpen windows and doors.
BInform your heating engineer.
Fitting and Modifications
BFitting of the appliance or many modifications to be appli-
ance may only be carried out by a compotent perEND.
BFlue systens must not be modified in any way.
BIf the appliance has a type B.. flue system : Ventilation
openings in doors, windows and walls must not be sealed
or restricted. If draught-proof windows are installed, meas-
ures must be taken to ensure there is an adequate supply
of air to the appliance for combustion.
Inspection / Maintenance
BWe recommend take out a to have the system regulary
serviced in order to ensure that it functions reliably and
safely.
BOnly use original spare parts.
Combustible materials
BDo not store or use any combustible materials (paper, thin-
ners, paints etc.) in the vicinty of the appliance.
Combustion Air / Ambient Air
BKeep combustion air/ambient air free of corrosive sub-
stances (e. g. halogenated hydrocarbons which contain
chlorine or fluorine compounds). In this way corrosion can
be prevented.
Instructions to the customer
BExplain to the customer how the appliance works and how
to operate it.
BAdvise the customer that he / she must not make any mod-
ifications to the appliance or carry out any repairs on it.
Safety instructions in this document are identi-
fied by a warning-triangle symbol and are print-
ed on a grey background.
Notes are identified by the symbol shown on
the left. They are bordered by horizontal lines
above and below the text.

2Service Functions
GB012 - 25K
4
2 Service Functions
2.1 Display Symbols 2.2 Service Function
Service functions are in divided in 2 level :
•1. Level (see page 5)
•2. Level (see page 6)
Fig. 1
1Stand by (On/off) Button
2„Up (+)“ Button
3„Down (-)“ Button
4Temparature Display (°C)
5Mode Button
Symbol Description
Save a parameter in service
mode
Air bleeding function is active
(service function : 1.2.C)
MAP (fan speed) (service func-
tion : 2.b.d).
Siphon filling mode is active.
Domestic hot water circuit is
active.
Key lock is active.
Summer mode.
Tab. 1
mode
1
0
23
4
bar
45
2
3
6 720 643 530-26.1O
1

2
Service Functions
GB012 - 25K 5
2.3 Service Function Overview
2.3.1 1. Service Level
Operation
Change or query of a service function :
BPress mode, “+”and “-”button for 5 second. The service
function will be shown on Display (e.g. 1.2.C).
BSelect the desired/requested service code with “+” or “-”
button.
BPress mode button again (for entering).
After that you will see the selected (default) value on
Display.
Changing / Adjustment of Value:
BChange the values with “+” or “-” button.
Storage/Save of Value :
BPress mode button until [ ] symbol will be shown on
Display.
Exit from Service Level :
BFor the exit from service level press the mode, “+”and “-”
button for 5 second or Stand by button.
The flow temperature will be shown again on display.
1. Level
Service Code Description Range Initial (Factory
setting)
1.2.C Automatical Air Purging (0 = offý, 1= active ) Total time : 2 min.
and 20 sec on/off intervall
0 - 1 0
1.2.F Operating Mode : (0 = Normal, 3= min. output, 4 = max. output) 0, 3 , 4 0
1.3.b Burner Anticycling 1 - 10 min. 3 min.
1.3.C Burner start hysterisis (for flow temp. NTC) 0 - 10 K 5 K
1.5.b Fan overrun 1 - 18 (x10) sec. 3 (=30 sec.)
1.6.A Last failure on memory 00 - FF -
1.6.d Display actual water flow rate by turbine ( l/min. ) 0 - 99
1.7.A LCD Backligth (1 = on, 0 = off) 0 - 1 1
Tab. 2 1. level service functions

2Service Functions
GB012 - 25K
6
2.3.2 2. Service Level
Operating
Change or query of a service function :
BTo enter to 2. service level must be entered first in 1.
level.
Press mode, “+”and “-”button for 5 second. The service
function onf1. level will be shown on Display (e.g.
1.2.C).
BTo enter to 2. level : Press both “+” and “-” buttons for 3
second. The service function of 2. level will be shown on
Display (e.g. 2.1.A).
BSelect the desired/requested service code with “+” or “-”
button.
BPress mode button again (for entering).
After that you will see the selected (default) value on
Display.
Changing / Adjustment of Value:
BChange the values with “+” or “-” button.
Storage/Save of Value :
BPress mode button until [ ] symbol will be shown on
Display.
Exit from Service level :
BFor the exit from service level press the mode, “+”and “-”
button for 5 second or Stand by button.
The flow temperature will be shown again on display.
2. Level
Service
Code Description Range Initial (Factory Setting)
2.1.A CH max. heat output 30 - 100 % 100 %
2.1.b DHW max. heat output (in winter mode) 30 - 100 % 100 %
2.2.b CH max flow temperature 35 - 82 °C 82 °C
2.3.d CH min. heat output 30 - 100 % 30 %
2.8.A Software version number e.g.. 162 112 -
2.8.E Reset to factory (default) setting 0 0
2.9.A Operation mode permanent : (0 = Normal, 1= min. power, 2 = max.
power)
0 - 2 0
2.9.E Delay time for the turbine ( each unit = 0,5 sec.) 1 - 6 2
2.9.F Pump over run) (CH circuit) 0 - 10 min. 3
2.A.A Actual flow temperature ºC -
2.A.b Actual DHW temperatur ºC -
2.A.F Actual combustion chamber temperature ºC -
2.b.d Selection of flue length (MAP Value) (0 = off, 1 - 10 : fan speed accord-
ing flue pipe length, see flue manuel for details)
0 - 10 0
2.b.F Solar mode delay time (sec.) 1 - 50 1
2.c.F Pump "over run” (DHW mode) ???? 0 - 30 sec. 5 sec.
2.0.A Gas Convertion (0 = NG, 1 = LPG) 0 -1 0
Tab. 3 2. level service functions

3
Failures / Errors
GB012 - 25K 7
3 Failures / Errors
3.1 Elimination of errrors
All regulation, control and safety equipment of
appliance is controlled by the control unit.
If any failure during operation occurs, symbol and
maybe will start to flash also. In additional the failure
code will be shown on display (e.g. EA).
If and symbol on display flash:
BFor the reset : Press mode and ”-” button until
and symbol expire on display.
The appliance will start up again and the flow
temperature will be displayed.
If only symbol flashes:
BSwitch the appliance first off and then on again by
means of the standby key.
The appliance will start up again and the flow
temperature will be displayed.
If a failure can not be eliminated :
BContact your approved installer or Customer Service
for assistance, providing details of the fault and the
appliance.
DANGER: Explosion !
BTurn off gas cock before working on
gasbearing components.
BCheck for leaks before working on
gasbearing components.
DANGER: Poisoning !
BCheck for leaks before working on
gasbearing components.
DANGER: Risk of electric shock !
BAlways disconnect the power supply to
the appliance at the mains before
carrying out any work on the electrical
systems and components (fuse, circuit
breaker).
NOTICE: Leaking water may damage the
Cotronic module.
BCover the Cotronic module before
working on any parts that carry water.
For an overview of faults, see page 7.

3Failures / Errors
GB012 - 25K
8
3.2 Failure / Error Codes Overview
Failure
Code on
Display Failure Descripton Steps
MAP not selected (Fan speed adjustment
according the flue pipe length).
Check the adjustment /selection via service func-
tion 2.b.d).
1H Combustion chamber NTC failure (behind
burner) : - when the temperature by CC NTC
reached to limit or
- when NTC not detected or open circuit
Check the and the heat exchanger surface,
whether is blocked or not. And check the sensor
and the connections.
2P Gradient limit : Temperature rises too rapidly
in heating mode.
Check the pump, system pressure and by-pass
circuit.
3A Fan sensor not detected. Check the fan.
3C Fan speed can not reached to target speed. Check the fan for the blockage and the electrical
supply.
4C Overheat lock-out by temperatur limiters
(STBs) (Flue gas + prim. Heatexchanger). In
this case ; Heat demands is blocked and
pump stops 3 min. later.
Check the system presseure, temperature sensor,
pump and fuses on board. Discharge the air in
system. Check also the flue gas pipe and heatex-
changer.
4Y Flow temperature sensor failure (pump is run-
ning).
Check the flow temperature sensor and the con-
nection.
6A Ignition lock-out (flame not detected) (pump is
running).
Check the gas cock, gas pressure, electrode and
the cable connection.
6C Safety valve leaks. Check the gas valve, the cable connection and
electrode set.
B3 Short circuit / failure in water level switch. Check the condensate water drain and recuperator
(condens-heatexchanger).
CL Domestic hot water temperature sensor not
correct installed or failure.
Check the sensor and cable connection.
d7 Modulator coil failure (regulator valve on gas
valve)
Check the cable connection.
Tab. 4 Failure codes

3
Failures / Errors
GB012 - 25K 9
3.3 Failure codes and corrections steps
4Cis flashing.
Overheat lock-out by temperatur limiters (2 x STB : Flue gas + prim. Heatexchanger). In this case ; Heat
demands is blocked and pump stops 3 minutes later.
Control Step Action
1. Is the system pressure between 1 - 2
bar?
yes: -->2.
no: BFill water in sysytem.
BBleed the system 1).
BPress RESET button and restart again.
4C failure still exist? -->2.
2. Is the circulation pump blocked ? yes: BEliminate the blockage (turn the shaft).
If not succesful :
BSwitch off the appliance.
BCut mains supply.
BDrain the water from appliance.
BChange the pump.
BFill with water and bleed the system again.
BConnect to main supply.
BSwitch on the appliance.
BPress RESET button and restart again.
4C failure still exist? -->3.
no: -->3.
3. Check the flue gas pipe line.
Is there any blockage ?
yes: BCheck the flue gas pipe and remove the block-
age.
BSwitch on the appliance.
BCihazý resetleyip yeniden çalýþtýrýn.
4C failure still exist? -->4.
no: -->4.
4. Check the recuperator.
Is there any blockage?
yes: BClean the recuperator. Replace if necessary.
BSwitch on the appliance.
BPress RESET button and restart again.
4C failure still exist? -->5.
no: -->5.
5. BSwitch off the appliance.
BCheck the temperature limiter
(STB) on recuperator.
Ist the circuit open or wrong
installed ?
no: -->6.
yes: BChange the temperature limiter (STB) or correct
the installation.
BSwitch on the appliance.
-->6.

3Failures / Errors
GB012 - 25K
10
6. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.
BEND
1) If the air inside not removed/discharged, can be also used the manuel air vent valve in recuparator.
4Cis flashing.
Overheat lock-out by temperatur limiters (2 x STB : Flue gas + prim. Heatexchanger). In this case ; Heat
demands is blocked and pump stops 3 minutes later.
Control Step Action

3
Failures / Errors
GB012 - 25K 11
6Ais flashing.
Ignition lock-out (flame not detected) (pump is running)
Control Step Action
1. Dose the burner flame can be seen? yes: -->6.
no: -->2.
2. Gas inlet cock open? yes: -->3.
no: BOpen the gas inlet cock.
BPress RESET button and restart again.
6A failure still exist? -->3.
3. Air in the gas pipe line? yes: BOpen the gas inlet cock.
BPress RESET button and restart again.
6A failure still exist? -->4.
no: -->4.
4. Ist the thermal gas inlet cock acti-
vated ?
(if it is installed)
yes: BChange the cock.
BPress RESET button and restart again.
6A failure still exist? -->5.
no: -->5.
5. Natural gas :
Is there any gas pressure regulator
at the house entrance ?
yes: BCheck if the montage of the gas pressure regu-
lator assembly is correct or not ? If necessory
correct it.
BM6Asure the gas inlet pressure. If there is a
deviation inform the gas distributor company.
BPress RESET button and restart again.
6A failure still exist? -->6.
no: -->6.
LPG (liquid gas):
Is there sufficient gas flow in the LPG
line to operate appliance ?
yes: -->6.
no: BIs the tank full enough ?
BIs there any air in the gas pipe?
BIs the external tank magnet valve tripgered ?
BIs the gas entry pressure OK? ( if too high check
the regulator).
BPress RESET button and restart again.
6A failure still exist?-->6.
6. Is the groun d i n g connection done
correctly?
yes: -->7.
no: BCorrect ground connection.
BPress RESET button and restart again.
6A failure still exist ? -->7.

3Failures / Errors
GB012 - 25K
12
7. Is the gas valve working ?
BSwitch off the appliance.
BPull out the gas valve cables.
BMeasure resistances from safety
valves.
yes: BConnect the cables.
BSwitch on the appliance.
BPress RESET button and restart again.
6A failure still exist ? -->8.
no: BCut mains supply.
BClose the gas inlet cock.
BChange the gas valve.
BOpen the gas inlet cock.
BConnect to main supply.
BConnect the cables.
BSwitch on the appliance.
BMake sure there is no gas l6Akage l6Aking.
BPress RESET button and restart again.
6A failure still exist ? -->8.
8. Is the ignition correct ? yes: -->12.
no: -->9.
9. Check connection of ignition cable
and electrode is correct or not?
yes: -->10.
no: BConnect the cable.
BPress RESET button and restart again.
6A failure still exist ? -->10.
10. Is the ignition cable assembled cor-
rectly?
yes: -->11.
no: BSwitch off the appliance.
BCorrect the ignition cable connection.
BSwitch on the appliance.
BPress RESET button and restart again.
6A failure still exist ? -->11.
11. Check ignition electrode for damage
and oxidation ?
yes: BSwitch off the appliance.
BChange the ignition cable.
BSwitch on the appliance.
BPress RESET button and restart again.
6A failure still exist ? -->12.
no: -->12.
12. BIs ionisation current OK ? yes: -->13.
no: BChange the ionisation electrode and check the
assembly of ignition brigde.
BPress RESET button and restart again.
6A failure still exist ? -->13.
6Ais flashing.
Ignition lock-out (flame not detected) (pump is running)
Control Step Action

3
Failures / Errors
GB012 - 25K 13
13. Cable harness is damaged. BSwitch off the appliance.
BCut mains supply.
BChange the cable harness.
BConnect to main supply.
BSwitch on the appliance.
BPress RESET button and restart again.
6A failure still exist ? -->14.
14. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance. END.
6Ais flashing.
Ignition lock-out (flame not detected) (pump is running)
Control Step Action

3Failures / Errors
GB012 - 25K
14
4Yis flashing.
Central heating flow temperature sensor failure (pump is running).
Control Step Action
1. Check if CH flow temperature sensor
(NTC) is damaged or not ?
BSwitch off the appliance.
BPull cables out.
BMeasure the electrical resistance
of the NTC sensor.
Are the measured values OK ?
(resistance table)
yes: BCheck the connection terminal on NTC.
4Y failure still exist ? -->2.
no: BChange NTC.
BConnect the cable.
BSwitch on the appliance.
4Y failure still exist ? -->2.
2. Check if the cables are damaged or
not?.
BSwitch off the appliance.
B·If NTC changed :
- disassemble the NTC cable from
NTC.
- measure the sensor resistance.
- assemble the NTC to NTC cable
again.
BPull out the 20 poled (main socket)
connector from the electronic
card.
BMeasure the electrical resistance
of NTC on socket. Are the meas-
ured resistance values at at NTC
and socket connection same?
yes: BChance the cable harness.
BSwitch on the appliance.
4Y failure still exist ? -->3.
no: -->3.
3. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.

3
Failures / Errors
GB012 - 25K 15
1His flashing.
Cumbustion chamber temperature sensor 1) is defect, not detected or overheating in cumbustion cham-
ber (pump runs continuously)
Control Step Action
1. Check if combustion chamber NTC
damaged or not and the position.
BSwitch off the appliance.
BPull the NTC cables out.
BMeasure NTC resistance.
Are the values correct ? (see NTC
values)
yes: BCheck the cable connection.
1H failure still exist ? -->2.
no: BChange the NTC.
BConnect the cable.
BSwitch on the appliance.
1H failure still exist ? -->2.
2. Check if cable damaged or not.
BSwitch off the appliance.
BIn case of NTC is cahnged :
- Pull the NTC cables out.
- Measure NTC resistance.
- Reconnect the NTC cable.
BPull out the 20 poled connector on
control unit.
BMeasure the NTC resistance
directly on 20 poled connector.
Are the measured values on NTC
and cocnector different ?
yes: BChange the cable harness.
BSwitch on the appliance.
1H failure still exist ? -->3.
no: -->3.
3. Is there any blockage on flue gas
pipe?
yes: BRemove the blockage.
1H failure still exist ? -->4.
no: -->4.
4. Is the correct MAP (fan speed) value
according flue gas pipe length
choosen ?
no: BAdjust correct MAP value according flue gas pipe
length and diameter. See capitel 7.2.
1H failure still exist ? -->5.
yes: -->5.
5. Is fan running correct ? no: BChange the fan.
1H failure still exist ? -->6.
yes: -->6.

3Failures / Errors
GB012 - 25K
16
6. Check the burner gas pressure. Are
the values OK ?
yes: BCorrect the gas pressure values. If not possible,
change the gas valve.
1H failure still exist ? -->7.
no: -->7.
7. Is the heat exchanger and recupera-
tor surface dirty or damaged (block-
age) ?
yes: BRemove the blockage.
1H failure still exist ? -->8.
no: -->8.
8. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.
1) The sensor is activated after 1 minute. After 3. failure the boiler is blocked. By first 2. time it will be reseted automaticly after 15 min.
1His flashing.
Cumbustion chamber temperature sensor 1) is defect, not detected or overheating in cumbustion cham-
ber (pump runs continuously)
Control Step Action

3
Failures / Errors
GB012 - 25K 17
CLis flashing.
DHW (Domestic Hot Water) NTC not installed correctly or defect.
The appliance doesn’ t run in summer mode. It works in winter mode and shows the failure code with
alternately.
Control Step Action
1. Check the DHW NTC whether it is cor-
rect installed or not.
CL failure still exist ? -->2.
2. Check if water NTC damaged or not ?.
BSwitch off the appliance.
BPull out NTC cables.
BMeasure resistance of NTC (Ohm).
Is the NTC resistance value OK ?
yes: BChange the cable harnness.
BSwitch on the appliance.
CL failure still exist ? -->3.
no: -->4.
3. Check if cable damaged or not.
BIn case of NTC is cahnged :
- Pull the NTC cables out.
- Measure NTC resistance.
- Reconnect the NTC cable.
BSwitch off the appliance.
BPull out the 20 poled connector on
control unit.
BMeasure the NTC resistance
directly on 20 poled connector. Are
the measured values on NTC and
cocnector different ?
yes: BChange the cable harnness.
BSwitch on the appliance.
CL failure still exist ? -->4.
no: -->4.
4. Check the DHW circuit in main heat
exchanger whether it is calcified or
not.
BIn case of calcification, clean it with special pump.
If necessary change the heat exchanger.
CL failure still exist ? -->5.
5. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.

3Failures / Errors
GB012 - 25K
18
2Pis flashing.
A fast temperature increase detected in central heating (CH) (> 2,7 K/sec).
The appliances will be resetet automaticly, if the flow temp. < 40 ºC.
Control Step Action
1. BCheck system pressure on
manome-ter.
Is the system pressure > 0,5 bar ?
yes: -->2.
no: BFill the system with water.
2P failure still exist ? -->2.
2. BIs there air in the system ?. yes: -->3.
no: BRemove the air in system.
2P failure still exist ? -->3.
3. BCheck if water is circulated ? yes: -->4.
no: BCheck and clean pump, filters and return and
flow valves.
2P failure still exist ? -->4.
4. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.

3
Failures / Errors
GB012 - 25K 19
3A is flashing.
Fan sensor not detected.
(This failure only occurs if there is a sensor or the cable physical defect)
Control Step Action
1. Is th fan cables damaged ? yes: BSwitch off the appliance.
BChange the cables.
BSwitch on the appliance.
3A failure still exist ? -->2.
no: -->2.
2. Is there any problem at fan sensor
and cable ?
BSwitch off the appliance.
BCheck the sensor and cable.
yes: BChange the cable and sensor.
BSwitch on the appliance.
3A failure still exist ? -->3.
no: -->3.
3. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.

3Failures / Errors
GB012 - 25K
20
3C is flashing.
Target fan speed can not reached or blockage problem.
Control Step Action
1. Is the flue gas pipe blocked ? no: -->2.
yes: BSwitch off the appliance.
BClean the flue gas pipe.
BSwitch on the appliance.
3C failure still exist? -->2.
2. Check the power voltage supply.
Is voltage below 160 V AC ?
yes: BSwitch off the appliance.
BInform related persons/company.
BSwitch on the appliance.
3C failure still exist? -->3.
no: -->3.
3. Check the fan it self. Is there any
blockage or others problems?
no: -->4.
yes : BSwitch off the appliance.
BChange the fan.
BSwitch on the appliance.
3C failure still exist? -->4.
4. Electronic card is defect. BSwitch off the appliance.
BCut mains supply.
BChange the electronic card.
BConnect to main supply.
BSwitch on the appliance.