Viessmann
Fault Codes

Listed below are the common Viessmann fault codes as described by the boiler manufacturer along with a possible cause.

Vitodens 200 Boiler Error Codes

Fault Code	System Behaviour	Cause of Problem
02	Burner control switches to lockout	Safety chain was activated
04, 05, 06, 08	Burner control switches to lockout	Fan speed too high/low at start
07, 09	Burner control switches to lockout	Basic level of air pressure threshold in standby mode not correct
0A	Burner control switches to lockout	Fault, fan speed
0D	Burner control switches to lockout	Reset button pressed repeatedly or while burner is running
1A, 1B	Burner blocked	Flow sensor 1, 2 faulty
1F	Burner blocked	Differential flow rate too large
25	Boiler operates with high boiler water temperature	Emissions test switch turned to “hand symbol” for 30 minutes already
26	Boiler operates with continuous relay test	Setting mode for maximum or minimum rated input active for 30 minutes already
35	Boiler does not activate	Reset button (pressed while burner is OFF) with emissions test switch turned to “hand symbol”
A2	N/A	KM-BUS fault to Vitocom
A5	N/A	Short circuit / open circuit

Fault Code 0B

Fault Code	System Behaviour	Cause of Problem
Vitodens 200	Burner control switches to lockout. Fan does not idle after auto reset (incorrect fan rpm).	Severe wind conditions in vent system
Vitodens 100-W	Burner blocked	Insufficient water flow, incorrect flow direction, defective flow switch.

Fault Code 0C

Fault Code	System Behaviour	Cause of Problem
Vitodens 100-W	Burner blocked	Insufficent power supply
Vitodens 200	Burner control switches to lockout	Flame signal still present after switching off

Fault Code

System Behaviour

Cause of Problem

Vitodens 100-W

Burner blocked

Insufficent power

supply

Vitodens 200

Burner control switches to lockout

Flame signal still present after switching off

Fault Code 0F

Fault Code	System Behaviour	Cause of Problem
Vitodens 222-F	Control mode	Code “0F” is only displayed in the fault history
Vitotronic 300 / Vitotronic 300-K, with Vitotronic 300 / Vitodens 200-W / Vitocontrol-S, with Vitotronic 100	Control mode / Controlled operation	Boiler service required
Vitotronic 200 / 300	Normal operation	Boiler service required
Vitocontrol-S, MW1 with Vitotronic 100 / Vitotronic 300-K, MW1S with Vitotronic 100	Control mode	Maintenance – “0F” is only displayed in the fault history

Fault Code 10

Fault Code	System Behaviour	Cause of Problem
Vitodens 200-W / 222-F / Vitotronic 300 / 200/ 200-H / 050/200-H / 300-K / vitocontrol-S	Boiler operates based on outdoor temperature of 32°F / 0°C	Short circuit – outdoor temperature sensor
Vitotronic 300-K, MW2S with Vitotronic 100 / Vitodens 100-W (combiPLUS) / 200-w / Vitocontrol-S, WB2B with Vitotronic 100	Controls as if the outdoor temperature / Constant Mode	Outdoor temperature sensor shorted out

Error Code 10, 14, F3, and F4

Fault Code	System Behaviour	Cause of Problem
Vitodens 200-W / 222-F / Vitotronic 300 / 200/ 200-H / 050/200-H / 300-K / vitocontrol-S	Boiler operates based on outdoor temperature of 32°F	Short circuit – outdoor temperature sensor
Vitotronic 300-K, MW2S with Vitotronic 100 / Vitodens 100-W (combiPLUS) / 200-w / Vitocontrol-S, WB2B with Vitotronic 100	Control as if the outdoor temperature is in constant mode	Outdoor temperature sensor shorted out

Fault Code 18 and D1

Fault Code	System Behaviour	Cause of Problem
Vitodens 100 / 200-W / 222-F / Vitotronic 300-K With 100 / Vitocontrol-S	Boiler operates based on outdoor temperature of 32°F / 0°C / Constant Mode	Outdoor temperature sensor cable broken
Vitotronic / 100 / 200 / 300 / 050/200-H /300-K / Vitocontrol-S, MW1 with Vitotronic 100	Operates on basis of 32°F / 0°C outdoor temperature	Open circuit – Outdoor temperature sensor
Vitotronic 200-H / Vitotronic 300-K, MW1B with Vitotronic 300 / Vitotronic 300-K, MW2B with Vitotronic 200	Controls as if the outdoor temperature	Lead break – Outdoor temperature sensor
Vitotronic 050/200-H	Activates after 0°C / 32°F outdoor temperature	Cable break – Outdoor temperature sensor
Vitodens 100-W	Burner in fault mode	DIP switch S2 is set to “ON”

Fault Code 19

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300	Activates after 0°C / 32°F outdoor temperature	Communication fault, wireless outdoor temperature sensor

Fault Code 20

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitotronic 300 / 300-K / 200 / 100	Stand-alone control unit without supply temperature sensor (possibly supply temperature not 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 w/o supply temperature sensor (supply temperature may 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 – System supply temperature sensor
Vitotronic 050/200-H< / 200 / 200-H / 300	Mixing valve closed	Short circuit – Supply temperature sensor / mixing valve circuit M1
Vitotronic 300-K, with Vitotronic 100	Vitotronic 300-K, MW1S controls in a stand-alone manner w/o strap-on sensor (supply temperature may 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

Fault Code 21

Fault Code	System Behaviour	Cause of Problem
Vitotronic 200 / 300	Operation without influence of return water temperature	Short circuit – Return water temperature sensor

Error Code 28

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100	Vitocontrol-S, VD2/CT3/CM2 controls in a stand-alone manner w/o supply temperature sensor (supply temperature may 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 in heating circuit with mixing valve M1 (heating circuit 1)
Vitotronic 300 Vitotronic / 300-K with Vitotronic 300 / 200	Stand-alone control unit without supply temperature sensor (possibly supply temperature not 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 may not be high enough)	Open circuit – Strap-on temperature sensor

Fault Code 29, 41, 49, F80, F81, F83, F88 and F89

Fault Code	System Behaviour	Cause of Problem
Vitotronic 200 / 300	Normal operation without influence of return water temperature	Open circuit 1 or 2 – Return water temperature sensor (of mixing valve circuit 1)

Fault Code 30

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S, with Vitotronic 100 / Vitocrossal 300 / Vitodens 200-W / 222-F / Vitotronic 100 / 200 / 300	Adjustable high limit burner is started and stopped	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

Fault Code 38

Fault Code	System Behaviour	Cause of Problem
Vitodens – 200-W / 222-F / COMBIPLUS	Burner blocked	Boiler water temperature sensor cable broken
Vitotronic 100 / 200 / 300 / Vitocontrol-S with Vitotronic 100	Burner is switched on and off by the adjustable high limit	Open circuit – Boiler temperature sensor
Vitotronic 300-K with Vitotronic 300 / Vitotronic 300-K with Vitotronic 300	The burner is started and stopped via a temperature controller	Lead break, boiler water temperature sensor
Vitodens 100-W	Burner blocked	Boiler water temperature sensor lead broken

Error Code 40 and 44

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Mixing valve closed	Heating circuit 2 with mixing valve supply short circuit on temperature sensor

Fault Code 41

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300	Operation without accounting for return water temperature	Short circuit – Return water temperature sensor of mixing valve circuit 2

Fault Code 48 and 4C

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Mixing valve closes / closed	Heating circuit 2 with mixing valve supply temperature sensor cable broken / open circuit

Fault Code 50, 51, 58 and 59

Fault Code	System Behaviour	Cause of Problem
Vitodens 200-W / 222-F	No DHW heating / Fault with DHW	Short circuit/open circuit – DHW tank temperature sensor or lead break

Error Code 52

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300	Control mode	Short circuit – Supply temperature sensor low-loss header
Vitodens 100-W CombiPLUS	Burner blocked (with CombiPLUS only)	Flow sensor shorted out (in CombiPLUS)

Fault Code 55, 56 and 57

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300-K, with Vitotronic 200	Control mode	Maintenance or error on Vitotronic 100 of boiler 5-8

Fault Code 5A, B7, and B8

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Control mode	Lead break, low-loss header – Supply temperature sensor
All Viessmann boilers	Burner blocked / control mode	Sensor cable broken

Error Code 5C, 5D, 5E and 5F

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300-K with Vitotronic 200	Control mode	Communication fault, Vitotronic 100 of boiler 5-8

Fault Code 60, 68, 70, 78, BD, BE and BF

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	– No output reduction	– Return control open	– Boiler with maximum temperature	Short/open circuit – Temperature sensor [17A]

Fault Code 80, 81, 82, 83 and FD

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner control unit in a fault state; system cools down; burner control unit locked out	Short circuit – Boiler water temperature sensor, burner control unit

Error Code 88, 89, and E6

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitotronic 300-K with Vitotronic 100 / 200	Control mode	Communication error

Fault Code 8C, 8D, 8E and 8F

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300	Burner control unit in an error mode	Lead break, boiler water temperature sensor, burner control unit

Fault code 90, 91, 92, 93, 94, 98, 99, 9A, 9B , 9C, 9E, 9F + AB

Fault Code	System Behaviour	Cause of Problem
Viessmann boilers	Control mode	Short circuit – Temperature sensor [5] / [6] / [7] / [10]

Error Code A0, A1, A2, AA, and AC

Fault Code	System Behaviour	Cause of Problem
Vitodens 200	Pump running at maximum speed	Open circuit – Internal BUS connection issue

Fault Code A3, B0, F1, FE1 and FE2

Fault Code	System Behaviour	Cause of Problem
Vitocrossal 300 / Vitodens 200-W / 222-F / 300	Control mode is in factory default setting	Programming unit is faulty

Fault Code A4

Fault Code	System Behaviour	Cause of Problem
222-F	Burner blocked. The venting program automatically starting	Air lock in the internal circulation pump or minimum flow rate not achieved

Fault Code A7

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitotronic 100 / Vitotronic 300-K with Vitotronic 300	Control mode (stays in factory default setting)	Isolation valve error coding OC:2, OC:3 or OC:4 set, and coding 4E:1 not set

Error Code A8

Fault Code	System Behaviour	Cause of Problem
All Boilers	Control mode issue	Programming unit communication fault

Fault Code A9, BA, BB, BC and FE0

Fault Code	System Behaviour	Cause of Problem
Vitodens 200	Boiler cools down	Sensor inputs are not read correctly

Fault Code AD

Fault Code	System Behaviour	Cause of Problem
Vitodens 200	Setting via service level not possible	Data points are not stored internal error VR20

Fault Code B1

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitotronic 100 / 200 / 300 / Vitotronic 300-K with Vitotronic 100	Test mode on emissions	Internal electronics error
Vitocontrol-S with Vitotronic 100 / Vitodens 200-W	Regulates as if the outside temperature was 32°F	Internal error
Vitotronic 050/200-H	Control characteristics undefined	Electronics internal error

Error Code B2

Fault Code	System Behaviour	Cause of Problem
All viessmann boilers	Control mode	Internal electronics error

Fault Code B3 and E5

Fault Code	System Behaviour	Cause of Problem
All boilers	Constant Mode	Invalid hardware recognised

Fault Code B4

Fault Code	System Behaviour	Cause of Problem
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 was 32°F (0°C)	Internal fault
Vitotronic 050/200-H	Undefined control characteristics	Internal electronics fault

Fault Code B5

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Control mode	External safety equipment

Error Code B6

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Control mode	Open circuit – KM bus to solar control unit communication error

Fault Code B9, ED, F0, FE5, FEC, FED, FEE, FEF, FFD + FFF

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitotronic 100 / 300 / Vitotronic 300-K with Vitotronic 300	Boiler cools down	Error maximum pressure limiter 1 2

Fault Code C1

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner control unit switches to lockout, this could be due to large line voltage fluctuations	Differential air pressure sensor open circuit

Fault Code C2-C8, CD-CF, D2-D8, DA-DF, and E0

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Boiler cools down	Fixed high limit has responded or fuse F2 has blown.

Error code C9, CA and CB

Fault Code	System Behaviour	Cause of Problem
All viessmann boilers	Boiler drives up to electronic maximum limit	Boiler does not log in at the cascade control unit

Error code CC and F0

Fault Code	System Behaviour	Cause of Problem
All viessmann boilers	Burner control unit is in fault mode	Ionisation current too high during calibration – Boiler temperature limiter responded air or blockage in system/pump error

Fault Code D4

Boiler cools down
Error with safety equipment at ‘X2/X3/X7’ of plug-in adaptor 2 for external safety equipment

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300 / Vitotronic 300-K with Vitotronic 300
Vitodens 200	Boiler is operating in emergency mode (after 30 mins BUS error) or boiler cools down	Internal bus error or open circuit internal bus connection

Fault Code D5

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner blocked	Flue gas temperature sensor not properly positioned – Check Sensor External pump fitted on system

Fault Code E1, E7, E8, E9, EA, EB, EC and FF2

Fault Code	System Behaviour	Cause of Problem
Vitodens 200-W / 222-F / Vitotronic 300	Burner in fault mode	Flow rate for heating hot water is too low during calibration / flow switch caused shutdown

Error Code E2 and E3

Fault Code	System Behaviour	Cause of Problem
All boilers	Burner in fault mode	Heating water flow rate too low during calibration; flow switch caused shutdown

Fault Code E4

Fault Code	System Behaviour	Cause of Problem
Vitotronic 300, Vitodens 200-W, 222-F, Vitocrossal 300, Vitocontrol-S with Vitotronic 100	Burner error	Burner start flame signal is too weak or missing

Fault Code EE and EF

Fault Code	System Behaviour	Cause of Problem
Vitocontrol-S with Vitotronic 100 / Vitocrossal 300 / Vitodens 200-W / 222-F / Vitotronic 300	Burner blocked	Faulty air pressure – switch air damper flap is stuck

Fault Code F5

Fault Code	System Behaviour	Cause of Problem
All viessmann boilers	Gas pressure switch shows no gas pressure / electrical connection error	Gas shut-off valve closed / gas pressure switch faulty / multiple problems with gas supply

Fault Code F6, 58, F9, FE1, FE2 and FF6

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner in error mode emergency operation	Fan not at standstill / plug-in connection error

Fault Code FA and FB

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Control mode	Communication fault with boiler

Error Code FB7, FF4, FF2, FF7, FF8 and FF9

Fault Code	System Behaviour	Cause of Problem
Vitocrossal 200	Case A: Burner control unit in a fault state; system cools down; burner control unit locked out. Case B: Type of coding card	Case A: Coding card not inserted in the burner control unit; incorrect or faulty coding card. Case B: Coding card does not match burner control unit.

Fault Code FC

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner in fault mode	Gas valve faulty or faulty modulation valve control; or vent system blocked

Error Code FE

Fault Code	System Behaviour	Cause of Problem
All Viessmann boilers	Burner blocked or in error mode	Strong interference (EMC) field nearby, or faulty main PCB

Error Code FE4

Fault Code	System Behaviour	Cause of Problem
Vitocrossal 200	Burner shuts down	Multiple detection of undervoltage

Fault Code FFA, FFB and FR

Fault Code	System Behaviour	Cause of Problem
Vitocrossal 200 / 400-620 / 186-311	Fan runs without demand; burner control unit in a fault state	Fan has not stopped; cable [100A] faulty; fan faulty; burner control unit faulty

Viessmann Error Code F4 EE

Viessmann error code F4 EE means that the condensate pipe has frozen and needs to be thawed. You can thaw out the pipe yourself fairly quickly and easily without the need for an engineer but don’t hesitate to contact one if you do not feel confident enough. .

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ViessmannFault Codes