When a
Viessmann boiler develops a problem, it may display a fault code on the control
panel. The fault codes will include a couple of letters or numbers (or a
combination of both) and are designed to help you and your heating engineer to
identify and solve any issues. Some of the Viessmann fault codes apply to all
Viessmann boilers, whereas others are only relevant to specific models.
If you’ve
noticed that a fault code has appeared on your Viessmann boiler and you want to
find out what it means, simply refer to the tables below.
Viessmann Boiler Fault Code 5C, 5D,
5E and 5F
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOTRONIC 300-K WITH
VITOTRONIC 200
CONTROL MODE – COMMUNICATION
FAULT – VITOTRONIC 100 OF BOILER 5-8
STAND-ALONE CONTROL UNIT
WITHOUT SUPPLY TEMPERATURE SENSOR (SUPPLY TEMPERATURE MIGHT NOT BE HIGH
ENOUGH)
SHORT CIRCUIT – COMMON SUPPLY
TEMPERATURE SENSOR
VITOCONTROL-S WITH VITOTRONIC
100 / VITOTRONIC 300-K WITH VITOTRONIC 200
VITOCONTROL-S CONTROLS IN A
STAND-ALONE MANNER WITHOUT SUPPLY TEMPERATURE SENSOR (SUPPLY TEMPERATURE
MIGHT NOT BE HIGH ENOUGH)
COMMON SUPPLY TEMPERATURE
SENSOR SHORTED OUT
VITOCROSSAL 300
REGULATES WITHOUT SUPPLY
TEMPERATURE SENSOR (LOW-LOSS HEADER)
SHORT CIRCUIT – SYSTEM FLOW
TEMPERATURE SENSOR
VITODENS 200-W / 222-F
REGULATES WITHOUT SUPPLY
TEMPERATURE SENSOR (LOW-LOSS HEADER)
SHORT CIRCUIT – SUPPLY SYSTEM
TEMPERATURE SENSOR
VITOTRONIC 020/200-H / 200 /
200-H / 300
MIXING VALVE CLOSES OR CLOSED
SHORT CIRCUIT – SUPPLY
TEMPERATURE SENSOR / MIXING VALVE CIRCUIT M1
VITORONIC 300-K WITH
VITOTRONIC 100
VITOTRONIC 300-K, MW1S
CONTROLS IN A STAND-ALONE MANNER WITHOUT STRAP-ON SENSOR (SUPPLY TEMPERATURE
MIGHT NOT BE HIGH ENOUGH)
SHORT CIRCUIT – STRAP-ON
TEMPERATURE SENSOR
VITODENS 200-W
REGULATES WITHOUT SUPPLY
TEMPERATURE SENSOR (LOW LOSS HEADER)
SYSTEM SUPPLY TEMPERATURE
SENSOR SHORTED OUT
Viessmann Boiler Fault Code 55, 56
and 57
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOTRONIC 300-K WITH
VITOTRONIC 200
CONTROL MODE
MAINTENANCE OR FAULT ON
VITOTRONIC 100 OF BOILER 5-8
Viessmann Boiler Fault Code EE and EF
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITODENS 100-W / 200 / 0 /
VITOTRONIC 300
BURNER BLOCKED
FAULTY AIR PRESSURE SWITCH –
AIR DAMPER (FLAP) STUCK
Viessmann Boiler Fault Code FE4
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOCROSSAL 200
BURNER SHUTS DOWN
MULTIPLE DETECTION OF
UNDERVOLTAGE
CASE A: BURNER CONTROL UNIT IN
A FAULT STATE; SYSTEM COOLS DOWN; BURNER CONTROL LOCKED OUT. CASE B: TYPE OF
CODING CARD
CASE A: CODING CARD NOT
INSERTED IN THE BURNER CONTROL UNIT; FAULTY OR INCORRECT CODING CARD. CASE B:
CODING CARD DOES NOT MATCH BURNER CONTROL UNIT
Viessmann Boiler Fault Code 50, 51,
58 and 59
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITODENS 200-W / 222-F
NO DHW HEATING / FAULT WITH
DHW
SHORT CIRCUIT/OPEN CIRCUIT –
DHW TANK TEMPERATURE SENSOR OR LEAD BREAK
Viessmann Boiler Fault Code A9, BA,
BB, BC & FE0
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITODENS 200
BOILER COOLS DOWN
SENSOR INPUTS ARE NOT READ
CORRECTLY
Viessmann Boiler Fault Code F-FA,
F-FB and FR
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOCROSSAL 200 / 400-620 /
186-311
FAN RUNS WITHOUT DEMAND;
BURNER CONTROL UNIT IN A FAULT STATE
FAN NOT STOPPED; CABLE 100A
FAULTY; FAN FAULTY; BURNER CONTROL UNIT FAULTY
Viessmann Boiler Fault Code 8C, 8D,
8E and 8F
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOTRONIC 300
BURNER CONTROL UNIT IN A FAULT
STATE
LEAD BREAK, BOILER WATER
TEMPERATURE SENSOR, BURNER CONTROL UNIT
Viessmann Boiler Fault Code 52
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOTRONIC 300
CONTROL MODE
SHORT CIRCUIT – SUPPLY
TEMPERATURE SENSOR LOW-LOSS HEADER
VITODENS 100-W COMBIPLUS
BURNER BLOCKED (COMBIPLUS
ONLY)
FLOW SENSOR SHORTED OUT
Viessmann Boiler Fault Code 38
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITODENS 200-W / 222-F /
COMBIPLUS
BURNER BLOCKED
BOILER WATER TEMPERATURE
SENSOR CABLE BROKEN
NORMAL OPERATION WITHOUT
INFLUENCE OF RETURN WATER TEMPERATURE
OPEN CIRCUIT 1 OR 2 – RETURN
WATER TEMPERATURE SENSOR (OF MIXING VALVE CIRCUIT 1)
Viessmann Boiler Fault Code A3, B0,
F1, E-E1 and F-E2
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOCROSSAL 300 / VITODENS
200-W / 222-F / 300
CONTROL MODE (STAYS IN FACTORY
DEFAULT SETTING)
FAULTY PROGRAMMING UNIT
Viessmann Boiler Fault Code 28
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOCONTROL-S WITH VITOTRONIC
100
VITOCONTROL-S, VD2/CT3/CM2
CONTROLS IN A STAND-ALONE MANNER W/O SUPPLY TEMPERATURE SENSOR (SUPPLY TEMPERATURE
MIGHT NOT BE HIGH ENOUGH)
OPEN CIRCUIT – COMMON SUPPLY
TEMPERATURE SENSOR
VITOCONTROL-S WITH VITOTRONIC
100 / VITOTRONIC 300-K WITH VITOTRONIC 100
VITOCONTROL-S, WB2B CONTROLS
IN A STAND-ALONE MANNER W/O SUPPLY TEMPERATURE SENSOR (SUPPLY TEMPERATURE
MIGHT NOT BE HIGH ENOUGH)
COMMON SUPPLY TEMPERATURE
SENSOR CABLE BROKEN
VITOCROSSAL 300 / VITODENS
200-W / 22-F
REGULATES WITHOUT SUPPLY
TEMPERATURE SENSOR (LOW-LOSS HEADER)
SYSTEM SUPPLY TEMPERATURE
SENSOR CABLE BROKEN
VITOTRONIC 050/200-H
MIXING VALVE CLOSES
CABLE BREAK – SUPPLY
TEMPERATURE SENSOR
VITOTRONIC 050/200-H
MIXING VALVE IS CLOSED
OPEN CIRCUIT – SUPPLY
TEMPERATURE SENSOR OF MIXING VALVE CIRCUIT M1
VITOTRONIC 200-H / VITOTRONIC
200 / 300
MIXING VALVE IS BEING CLOSED
LEAD BREAK, SUPPLY TEMPERATURE
SENSOR, HEATING CIRCUIT WITH MIXING VALVE M1 (HEATING CIRCUIT 1)
VITOTRONIC 300 / 300-K WITH
VITOTRONIC 300 / 200
STAND-ALONE CONTROL UNIT
WITHOUT SUPPLY TEMPERATURE SENSOR (SUPPLY TEMPERATURE MIGHT NOT BE HIGH
ENOUGH)
LEAD BREAK, COMMON SUPPLY
TEMPERATURE SENSOR
VITOTRONIC 300-K WITH
VITOTRONIC 100
VITOTRONIC 300-K, MW1S
CONTROLS IN A STAND-ALONE MANNER W/O STRAP-ON SENSOR (SUPPLY TEMPERATURE
MIGHT NOT BE HIGH ENOUGH)
OPEN CIRCUIT – STRAP-ON
TEMPERATURE SENSOR
Viessmann Boiler Fault Code B1
BOILER MODEL
SYSTEM BEHAVIOUR & DIAGNOSIS
VITOCONTROL-S WITH VITOTRONIC
100 / VITOTRONIC 100 / 200 / 300 / VITOTRONIC 300-K WITH VITOTRONIC 100
EMISSIONS TEST MODE
INTERNAL ELECTRONICS FAULT
VITOCONTROL-S WITH VITOTRONIC
100 / VITODENS 200-W
REGULATES AS IF THE OUTSIDE TEMPERATURE
IS 32°F (0°C)
INTERNAL FAULT
VITOTRONIC 020/200-H
UNDEFINED CONTROL
CHARACTERISTICS
INTERNAL ELECTRONICS FAULT
BURNER IS STARTED AND STOPPED
VIA AN ADJUSTABLE HIGH LIMIT
SHORT CIRCUIT – BOILER WATER
TEMPERATURE SENSOR
VITOCONTROL-S WITH VITOTRONIC
100 / VITODENS 100-W (COMBIPLUS) / 200-1
BURNER BLOCKED
BOILER WATER TEMPERATURE
SENSOR SHORTED OUT
Viessmann Boiler Fault Codes – All
Viessmann Boilers
FAULT CODE
SYSTEM BEHAVIOUR & DIAGNOSIS
B3 and E5
CONSTANT MODE – INVALID
HARDWARE RECOGNISED
FA and FB
CONTROL MODE – COMMUNICATION
FAULT
A8
CONTROL MODE – COMMUNICATION
FAULT – PROGRAMMING UNIT
90, 91, 92, 93, 94, 98, 99,
9A, 9B, 9C, 9E, 9F and AB
CONTROL MODE – SHORT CIRCUIT –
TEMPERATURE SENSOR [5] / [6] / [7] / [10]
C9, CA and CB
BOILER DRIVES UP TO ELECTRONIC
MAXIMUM LIMIT
BOILER DOES NOT LOG IN AT THE
CASCADE CONTROL UNIT
5A, B7 and B8
CONTROL MODE – LEAD BREAK, LOW-LOSS HEADER SUPPLY
TEMPERATURE SENSOR
BURNER BLOCKED / CONTROL MODE
– SENSOR CABLE BROKEN
CC and F0
BURNER IN FAULT MODE
IONISATION CURRENT TOO HIGH
DURING CALIBRATION – BOILER TEMPERATURE LIMITER RESPONDED (F2) – AIR OR
BLOCKAGE IN SYSTEM/PUMP FAILURE
B6
CONTROL MODE
OPEN CIRCUIT – KM BUS TO SOLAR
CONTROL UNIT – EXTENSION AM1 / DE1-DE3 M1 – COMMUNICATION FAULT
D5
BURNER BLOCKED
FLUE GAS TEMPERATURE SENSOR NOT
PROPERLY POSITIONED / CHECK SENSOR EXTERNAL PUMP FITTED ON THE SYSTEM (100-W)
A-3 FAULT
60, 68, 70, 78, BD, BE and BF
NO OUTPUT REDUCTION – RETURN
CONTROL OPEN – BOILER WITH MAXIMUM TEMPERATURE
SHORT/OPEN CIRCUIT –
TEMPERATURE SENSOR [17A]
E2 and E3
BURNER BLOCKED – FAULT: SUPPLY
VOLTAGE 24V
40 and 44
MIXING VALVE CLOSES
HEATING CIRCUIT 2 WITH MIXING
VALVE SUPPLY SHORT CIRCUIT ON TEMPERATURE SENSOR
48 and 4C
MIXING VALVE CLOSES OR CLOSED
HEATING CIRCUIT 2 WITH MIXING
VALVE SUPPLY TEMPERATURE SENSOR CABLE BROKEN / OPEN CIRCUIT
FC
BURNER IN FAULT MODE
GAS VALVE FAULTY OR FAULTY
MODULATION VALVE CONTROL / OR VENT SYSTEM BLOCKED.
CHECK THE FAN, FAN CABLE AND
PCB
FE
BURNER BLOCKED OR IN FAULT
MODE
STRONG INTERFERENCE (EMC)
FIELD NEARBY OR FAULTY MAIN PCB
B2
CONTROL MODE – INTERNAL
ELECTRONICS FAULT
B5
CONTROL MODE – EXTERNAL SAFETY
EQUIPMENT
80, 81, 82, 83 and FD
BURNER CONTROL UNIT IN A FAULT
STATE; SYSTEM COOLS DOWN; BURNER CONTROL UNIT LOCKED OUT
SHORT CIRCUIT – BOILER WATER TEMPERATURE
SENSOR, BURNER CONTROL UNIT
B4
NORMAL OPERATION / FAULT
AROUND BURNER CONTROL UNIT
INTERNAL FAULT (PCB)
C2-C8, CD-CF, D2-D8, DA-DF and
E0
BOILER COOLS DOWN
FIXED HIGH LIMIT HAS RESPONDED
OR FUSE F2 HAS BLOWN
F5
GAS PRESSURE SWITCH SHOWS NO
GAS PRESSURE / ELECTRICAL CONNECTION FAULT
GAS SHUT-OFF VALVE CLOSED; GAS
PRESSURE SWITCH FAULTY; MULTIPLE GAS PROBLEMS WITH GAS SUPPLY
F6, 58, F9, F-E1, F-E2 and
F-F6
BURNER IN FAULT MODE /
EMERGENCY OPERATION
FAN NOT AT STANDSTILL /
PLUG-IN CONNECTION