Do you have a Viessmann Boiler Error Code problem?
Even the most reliable boiler can occasionally malfunction. If your Viessmann boiler is displaying an error code and you don’t have the manual to hand, you can use the detailed lists below to work out what’s wrong.
You shouldn’t try to fix anything that involves removing the boiler’s case or any parts; only a Gas Safe engineer is permitted to do so, as well as unscrewing any panels.
If you can’t find your Viessmann error code below, or simply want to speak to an experienced heating engineer to work out what to do about your fault, you can book a 15-minute video call at Herofix.com.
Viessmann boilers we have covered in this error code list:
Vitodens 200 Boiler Error Codes
| Error Code | System Behaviour | Cause of problem |
|---|---|---|
| 2 | 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 |
Error Code 0B
| Error 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. |
Error Code 0C
| Error 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 | Insufficient power supply |
| Vitodens 100-W | Burner blocked | Insufficient water flow, incorrect flow direction, defective flow switch. | Insufficient power supply |
| Vitodens 200 | Burner control switches to lockout. Fan does not idle after auto reset (incorrect fan rpm). | Severe wind conditions in vent system | Insufficient power supply |
| Vitodens 100-W | Burner blocked | Insufficient water flow, incorrect flow direction, defective flow switch. |
Error Code 0F
| Error 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 |
Error Code 10
| Error 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 | Flame lockout |
| 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
| Error 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 | Flame lockout |
| 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
| Error 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 |
Error Code 18 and D1
| Error 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” |
Error Code 19
| Error Code | System Behaviour | Cause of problem |
|---|---|---|
| Vitotronic 300 | Activates after 0°C / 32°F outdoor temperature | Communication fault, wireless outdoor temperature sensor |
Error Code 20
| Error 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 |
Error Code 21
| Error 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
| Error 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 |
Error Code 29, 41, 49, F80, F81, F83, F88 and F89
| Error 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) |
Error Code 38
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Viessmann boilers | Mixing valve closed | Heating circuit 2 with mixing valve supply short circuit on temperature sensor |
Error Code 41
| Error 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 |
Error Code 48 and 4C
| Error 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 |
Error Code 50, 51, 58 and 59
| Error 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
| Error 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) |
Error Code 55, 56 and 57
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitotronic 300-K, with Vitotronic 200 | Control mode | Maintenance or error on Vitotronic 100 of boiler 5-8 |
Error Code 5A, B7, and B8
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitotronic 300-K with Vitotronic 200 | Control mode | Communication fault, Vitotronic 100 of boiler 5-8 |
Error Code 5C, 5D, 5E and 5F
| Error 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] |
Error Code 80, 81, 82, 83 and FD
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitocontrol-S with Vitotronic 100 / Vitotronic 300-K with Vitotronic 100 / 200 | Control mode | Communication error |
Error Code 8C, 8D, 8E and 8F
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitotronic 300 | Burner control unit in an error mode | Lead break, boiler water temperature sensor, burner control unit |
Error code 90, 91, 92, 93, 94, 98, 99, 9A, 9B , 9C, 9E, 9F and AB
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitodens 200 | Pump running at maximum speed | Open circuit – Internal BUS connection issue |
Error Code A3, B0, F1, FE1 and FE2
| Error 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 |
Error Code A4
| Error 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 |
Error Code A7
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Boilers | Control mode issue | Programming unit communication fault |
Error Code A9, BA, BB, BC and FE0
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitodens 200 | Boiler cools down | Sensor inputs are not read correctly |
Error Code AD
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitodens 200 | Setting via service level not possible | Data points are not stored internal error VR20 |
Error Code B1
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All viessmann boilers | Control mode | Internal electronics error |
Error Code B3 and E5
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All boilers | Constant Mode | Invalid hardware recognised |
Error Code B4
| Error 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 |
Error Code B5
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Viessmann boilers | Control mode | External safety equipment |
Error Code B6
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Viessmann boilers | Control mode | Open circuit – KM bus to solar control unit communication error |
Error Code B9, ED, F0, FE5, FEC, FED, FEE, FEF, FFD and FFF
| Error 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 |
Error Code C1
| Error 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 |
Error Code C2-C8, CD-CF, D2-D8, DA-DF, and E0
| Error 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
| Error 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
| Error 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 |
Error Code D4
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitotronic 300 / Vitotronic 300-K with Vitotronic 300 | Boiler cools down | Error with safety equipment at ‘X2/X3/X7’ of plug-in adaptor 2 for external safety equipment |
| 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 |
Error Code D5
| Error 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 |
Error Code E1, E7, E8, E9, EA, EB, EC and FF2
| Error 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
| Error Code | System Behaviour | |
|---|---|---|
| All boilers | Burner in fault mode | Heating water flow rate too low during calibration; flow switch caused shutdown |
Error Code E4
| Error 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 |
Error Code EE and EF
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitocontrol-S with Vitotronic 100 / Vitocrossal 300 / Vitodens 200-W / 222-F / Vitotronic 300 / Vitodens 200 WB2B | Burner blocked | Broken gas valve or faulty air pressure – switch air damper flap is stuck |
Error Code F5
| Error 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 |
Error Code F6, 58, F9, FE1, FE2 and FF6
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Viessmann boilers | Burner in error mode emergency operation | Fan not at standstill / plug-in connection error |
Error Code FA and FB
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| All Viessmann boilers | Control mode | Communication fault with boiler |
Error Code FB7, FF4, FF2, FF7, FF8 and FF9
| Error 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 A: Coding card not inserted in the burner control unit; incorrect or faulty coding card. |
| Vitocrossal 200 | Case B: Type of coding card | Case B: Coding card does not match burner control unit. |
Error Code FC
| Error 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
| Error 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
| Error Code | System Behaviour | Cause of Problem |
|---|---|---|
| Vitocrossal 200 | Burner shuts down | Multiple detection of undervoltage |
Error Code FFA, FFB and FR
| Error 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
During the winter months, you may see Viessmann error code F4 EE, which means that the boiler’s condensate pipe has frozen. Thawing it is something that you can undertake yourself, so there’s no need to call out an engineer, unless you don’t feel confident enough to do so.
Are you feeling overwhelmed by all those error codes? Don’t worry! Qualified, experienced professionals are on hand to help diagnose your fault and plan how to fix it. You can book a 15-minute video call with one at Herofix.com.
