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In the unfortunate event that your Viessmann boiler develops an issue, it will display a fault code. So that you can quickly identify what the fault code means and what should be your next course of action, we have developed the below fault code finders for the Viessmann range. Just search for the fault code that your boiler is displaying and the fault code finder will provide you with a diagnosis, this will assist you should you need to contact an engineer.
Displayed fault code | System characteristics | Cause | Measures |
---|---|---|---|
10 | Constant mode | Short circuit, outside temperature sensor | Check the outside temperature sensor and lead. |
18 | Constant mode | Lead break, outside temperature sensor | Check the outside temperature sensor and lead. |
30 | Burner blocked | Short circuit, boiler water temperature sensor | Check boiler water temperature sensor. |
38 | Burner blocked | Lead break, boiler water temperature sensor | Check boiler water temperature sensor. |
51 | No DHW heating | Short circuit, outlet temperature sensor | Check sensor. |
52 | Burner blocked | Short circuit, flow sensor | Check connections and lead; replace sensor if required. |
59 | No DHW heating | Lead break, outlet temperature sensor | Check sensor. |
5A | Burner blocked | Lead break, flow sensor | Check connections and lead; replace sensor if required. |
A9 | Control mode without OpenTherm influence | Communication error, OpenTherm device | Check connections and lead; replace OpenTherm if required. |
b0 | Burner blocked | Short circuit, flue gas temperature sensor | Check sensor. |
b8 | Burner blocked | Lead break, flue gas temperature sensor | Check sensor. |
E3 | Burner in a fault state | Fault in safety chain | Check the temperature limiter and connecting cables. |
E5 | Burner blocked | Internal fault | Check the ionisation electrode and connecting cables. |
F0 | Burner blocked | Internal fault | Replace control unit. |
F1 | Burner in a fault state | Max. flue gas temperature exceeded | Check heating system fill level. Check circulation pump. Vent the system. |
F2 | Burner in a fault state | Temperature limiter has responded | Check heating system fill level. Check circulation pump. Vent the system. Check the temperature limiter and connecting cables . Press "Reset" |
F3 | Burner in a fault state | Flame signal is al ready present at burner start | Check ionisation electrode and connecting cable. Press "Reset" |
F4 | Burner in a fault state | No flame signal detected | Check the ignition/ionisation electrode and connecting cables, check the gas pressure, check the gas train, ignition, ignition module and condensate drain. Press "Reset" |
F8 | Burner in a fault state | Fuel valve closes too late | Check gas train. Check both control paths. Press "Reset" |
F9 | Burner in a fault state | Fan speed too low during burner start | Check fan, fan connecting cables and power supply; check fan control. Press "Reset" |
FA | Burner in a fault state | Fan idle state not reached | Check fan, fan connecting cables and power supply; check fan control. Press "Reset" |
FC | Burner blocked | Electrical fan control (control unit) faulty | Check fan connecting cable; replace if required, or replace control unit. |
Fd | Burner blocked | Fault, burner control unit sensor | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press "Reset" . Replace control unit if fault persists. |
FF | Burner blocked | Fault, burner control unit sensor | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press "Reset" . Replace control unit if fault persists. |
––– | Burner blocked | Communication error between burner control unit and programming unit | Check connecting cable. Press "Reset". Replace burner control unit or programming unit if the fault persists |
Displayed fault code | System characteristics | Cause | Measures |
---|---|---|---|
10 | Constant mode | Short circuit, outside temperature sensor | Check the outside temperature sensor and lead. |
18 | Constant mode | Lead break, outside temperature sensor | Check the outside temperature sensor and lead. |
30 | Burner blocked | Short circuit, boiler water temperature sensor | Check boiler water temperature sensor. |
38 | Burner blocked | Lead break, boiler water temperature sensor | Check boiler water temperature sensor. |
51 | No DHW heating | Short circuit, outlet temperature sensor | Check sensor. |
52 | Burner blocked | Short circuit, flow sensor | Check connections and lead; replace sensor if required. |
59 | No DHW heating | Lead break, outlet temperature sensor | Check sensor. |
5A | Burner blocked | Lead break, flow sensor | Check connections and lead; replace sensor if required. |
A9 | Control mode without OpenTherm influence | Communication error, OpenTherm device | Check connections and lead; replace OpenTherm if required. |
b0 | Burner blocked | Short circuit, flue gas temperature sensor | Check sensor . |
b8 | Burner blocked | Lead break, flue gas temperature sensor | Check sensor. |
E3 | Burner in a fault state | Fault in safety chain | Check the temperature limiter and connecting cables. |
E5 | Burner blocked | Internal fault | Check the ionisation electrode and connecting cables. |
F0 | Burner blocked | Internal fault | Replace control unit. |
F1 | Burner in a fault state | Max. flue gas temperature exceeded | Check heating system fill level. Check circulation pump. Vent the system. |
F2 | Burner in a fault state | Temperature limiter has responded | Check heating system fill level. Check circulation pump. Vent the system. Check the temperature limiter and connecting cables. Press "Reset". |
F3 | Burner in a fault state | Flame signal is al ready present at burner start sensor | Check ionisation electrode and connecting cable. Press "Reset" burner start. |
F4 | Burner in a fault state | No flame signal detected | Check the ignition/ionisation electrode and connecting cables, check the gas pressure, check the gas train, ignition, ignition module and condensate drain. Press "Reset . |
F8 | Burner in a fault state | Fuel valve closes too late | Check gas train. Check both control paths. Press "Reset. |
F9 | Burner in a fault state | Fan speed too low during burner start | Check fan, fan connecting cables and power supply; check fan control. Press "Reset. |
FA | Burner in a fault state | Fan idle state not reached | Check fan, fan connecting cables and power supply; check fan control. Press "Reset. |
FC | Burner blocked | Electrical fan control (control unit) faulty | Check fan, fan connecting cables and power supply; check fan control. Press "Reset. |
Fd | Burner blocked | Fault, burner control unit sensor | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press "Reset". Replace control unit if fault persists |
FF | Burner blocked | Fault, burner control unit sensor | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press "Reset". Replace control unit if fault persists |
––– | Burner blocked | Communication error between burner control unit and programming unit | Check connecting cable. Press "Reset. Replace burner control unit or programming unit if the fault persists. |
Fault code displayed | System characteristics | Cause | Measures |
---|---|---|---|
0A | Burner blocked | CO limiter (if installed) has responded. CO concentration too high. | Check the heating system. Remove the cause of escaping CO. |
0A | Burner blocked | Gas pressure switch (if installed) has responded. Gas pressure too low. | Check the gas supply. |
0C | Burner blocked | Mains voltage too low | Check the power supply. |
10 | Continuous operation | Short circuit, outside temperature sensor | Check the outside temperature sensor and lead . |
18 | Continuous operation | Lead break, outside temperature sensor | Check the outside temperature sensor and lead . |
30 | Burner blocked | Short circuit, boiler water temperature sensor | Check boiler water temperature sensor. |
38 | Burner blocked | Lead break, boiler water temperature sensor | Check boiler water temperature sensor. |
50 | No DHW heating | Short circuit, cylinder temperature sensor | Check sensor. |
51 | No DHW heating | Short circuit, cylinder outlet sensor | Check sensor. |
58 | No DHW heating | Lead break, cylinder temperature sensor | Check sensor. |
59 | No DHW heating | Lead break, outlet temperature sensor | Check sensor. |
A3 | Burner blocked. | Flue gas temperature sensor incorrectly positioned. | Fit flue gas temperature sensor correctly. |
A9 | Control mode without OpenTherm device | Communication error, OpenTherm device | Check connections and lead; replace OpenTherm device if required. |
b0 | Burner blocked | Short circuit, flue gas temperature sensor | Check sensor. |
b7 | Emergency mode | Burner control unit fault | Turn the ON/OFF switch OFF and ON again. |
b8 | Burner blocked | Lead break, flue gas temperature sensor | Check sensor. |
E3 | Burner in a fault state | Fault in safety chain | Check the temperature limiter and connecting cables. Check the control unit, and replace if required. |
E5 | Burner blocked | Internal fault | Check the ionisation electrode and connecting cables. Press reset. |
F0 | Burner blocked | Internal fault | Replace control unit. |
F1 | Burner in a fault state | Max. flue gas temperature exceeded | Check heating system fill level. Check circulation pump. Vent the system. Press reset. |
F2 | Burner in a fault state | Temperature limiter has responded | Check heating system fill level. Check circulation pump. Vent the system. Check the temperature limiter and connecting cables. Press reset . |
F3 | Burner in a fault state | Flame signal is already present at burner start | Check ionisation electrode and connecting cable. Press reset . |
F4 | Burner in a fault state | No flame signal detected | Check the ignition/ionisation electrode and connecting cable, the gas pressure, the gas train, ignition and condensate drain. Press reset . |
F8 | Burner in a fault state | Fuel valve closes too late | Check gas train. Check both control paths. Press reset . |
F9 | Burner in a fault state | Fan speed too low during burner start | Check fan, fan connecting cables and power supply to fan; check fan control. Press reset. |
FA | Burner in a fault state | Fan idle state not reached | Check fan, fan connecting cables and fan control. Press reset. |
FC | Burner blocked | Electrical fan control (control unit) faulty | Check fan connecting cable; replace if required, or replace control unit. |
Fd | Burner blocked | Burner control unit fault | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press reset . Replace control unit if fault persists. |
FF | Burner blocked | Burner control unit fault | Check ignition electrodes and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press reset . Replace control unit if fault persists. |
Fault code displayed | System characteristics | Cause | Measures |
---|---|---|---|
10 | Regulates as if the outside temperature were 0 °C. | Short circuit, outside temperature sensor | Check outside temperature sensor. |
18 | Regulates as if the outside temperature were 0 °C. | Lead break, outside temperature sensor | Check outside temperature sensor. |
19 | Regulates as if the outside temperature were 0 °C. | Communication interruption, outside temperature sensor RF | Check wireless connection. Place outside temperature sensor RF close to the boiler. Forget outside temperature sensor, then pair again .Replace outside temperature sensor RF. |
20 | Regulates without flow temperature sensor (low loss header). | Short circuit, system flow temperature sensor | Check low loss header sensor . |
21 | Control mode Display fault in energy cockpit | Sensor outside tolerance range | Check sensors on DHW cylinder and collectors. |
22 | Control mode Display fault in energy cockpit | Sensor outside tolerance range | Check sensors on DHW cylinder and collectors. |
23 | Control mode Display fault in energy cockpit | Incorrect commissioning | Determine solar circuit flow rate and enter value established. |
24 | Control mode Display fault in energy cockpit | DHW circulation pump shut down | Check setting of parameter 39 ("General" group). If required, carry out an actuator test. |
25 | Control mode Display fault in energy cockpit | Transfer pump not working | Check setting of parameter 20 ("Solar" group). If required, carry out an actuator test. |
26 | Control mode Display fault in energy cockpit | DHW circulation pump and transfer pump not working | Check settings of parameter 39 ("General" group) and parameter 20 ("Solar" group). If required, carry out an actuator test. |
27 | Control mode Display fault in energy cockpit | Incorrect commissioning | Determine solar circuit flow rate and enter value established. |
28 | Regulates without flow temperature sensor (low loss header). | Lead break, system flow temperature sensor | Check low loss header sensor If no low loss header sensor is connected, set parameter 52:0. |
2A | Control mode Display fault in energy cockpit | Solar circuit flow and return interchanged. | Check solar circuit flow and return and swap over if required. |
30 | Burner blocked | Short circuit, boiler water temperature sensor | Check boiler water temperature sensor . |
38 | Burner blocked | Lead break, boiler water temperature sensor | Check boiler water temperature sensor. |
40 | Mixer closes. | Short circuit, flow temperature sensor, heating circuit 2 (with mixer) | Check flow temperature sensor. |
44 | Mixer closes. | Short circuit, flow temperature sensor, heating circuit 3 (with mixer) | Check flow temperature sensor. |
48 | Mixer closes. | Lead break, flow temperature sensor, heating circuit 2 (with mixer) | Check flow temperature sensor. |
49 | Mixer closes. | Incorrect assignment of extension for mixer, heating circuit 2 | Check and adjust rotary selector S1. |
4C | Mixer closes. | Lead break, flow temperature sensor, heating circuit 3 (with mixer) | Check flow temperature sensor . |
4D | Mixer closes. | Incorrect assignment of extension for mixer, heating circuit 3 | Check and adjust rotary selector S1. |
50 | No DHW heating by the boiler | Short circuit, cylinder temperature sensor or comfort sensor | Check cylinder temperature sensor or comfort sensor. |
51 | No DHW heating by the boiler | Short circuit, outlet temperature sensor | Check outlet temperature sensor. |
58 | No DHW heating by the boiler | Lead break, cylinder temperature sensor or comfort sensor | Check cylinder temperature sensor or comfort sensor . |
59 | No DHW heating by the boiler | Lead break, outlet temperature sensor | Check outlet temperature sensor. |
90 | Control mode | Short circuit, temperature sensor | Check sensor on solar control module. |
91 | Control mode | Short circuit, temperature sensor | Check sensor on solar control module. |
92 | No solar DHW heating | Short circuit, collector temperature sensor | Check temperature sensor on solar control module or sensor on the Vitosolic. |
93 | Control mode | Short circuit, collector return temperature sensor | Check temperature sensor at terminal S3 on the Vitosolic 100. |
94 | No solar DHW heating | Short circuit, cylinder temperature sensor | Check temperature sensor on solar control module or sensor on the Vitosolic. |
95 | Burner blocked | CO limit exceeded | Danger An increased concentration of carbon monoxide can cause potentially fatal car- bon monoxide poisoning. Observe the safety instructions at the beginning of this manual. Determine the cause of the increased CO level. Remedy the fault. Press Test on the CO limiter. The alarm is switched off. The burner starts again once the CO level is below the CO limit. |
96 | Burner blocked | CO limiter sensor fault | Replace the CO limiter. If the system is to be temporarily operated without CO limiter, set parameter 49:0. |
98 | Control mode | Lead break, temperature sensor | Check sensor on solar control module. |
99 | Control mode | Lead break, temperature sensor | Check sensor on solar control module. |
9A | No solar DHW heating | Lead break, collector temperature sensor | Check temperature sensor on solar control module or sensor on the Vitosolic. |
9B | Control mode | Lead break, collector return temperature sensor | Check temperature sensor at terminal S3 on the Vitosolic 100. |
9C | No solar DHW heating | Lead break, cylinder temperature sensor | Check temperature sensor on solar control module or sensor on the Vitosolic. |
9E | Control mode | No flow rate in solar circuit or flow rate too low, or temperature limiter has responded. | Check solar circuit pump and solar circuit. Acknowledge fault message. |
9F | Control mode | Solar control module or Vitosolic fault | Replace solar control module or Vitosolic. |
A3 | Burner blocked | Flue gas temperature sensor incorrectly positioned | Fit flue gas temperature sensor correctly. |
A7 | Control mode as per delivered condition | Programming unit faulty | Replace the programming unit. |
A8 | Burner blocked. The venting program is started automatically. | Air in the internal circulation pump or minimum flow rate not achieved | Vent the system if the fault message persists. |
A9 | If a heating circuit with mixer is connected, the burner operates at its lower heating output. If only one heating circuit without mixer is connected, the burner is blocked. | Internal circulation pump blocked | Check circulation pump. |
B0 | Burner blocked | Short circuit, flue gas temperature sensor | Check flue gas temperature sensor. |
B1 | Control mode as per delivered condition | Communication error, programming unit | Check connections; replace programming unit if necessary. |
B5 | Control mode as per delivered condition | Internal fault | Replace control unit. |
B7 | Burner blocked | Boiler coding card fault | Plug in boiler coding card or replace if faulty. |
B8 | Burner blocked | Lead break, flue gas temperature sensor | Check flue gas temperature sensor. |
BA | Mixer regulates to 20 °C flow temperature. | Communication error, extension kit for heating circuit 2 (with mixer) | Check extension kit connections and assignment. |
BB | Mixer regulates to 20 °C flow temperature. | Communication error, extension kit for heating circuit 3 (with mixer) | Check extension kit connections and assignment. |
BC | Control mode without remote control | Communication error, Vitotrol remote control, heating circuit 1 (without mixer) | Check connections, cable, parameter "A0" in the "Heating circuit" group and remote control settings . For wireless remote controls: check connection, place remote control close to the boiler. |
BD | Control mode without remote control | Communication error, Vitotrol remote control, heating circuit 2 (with mixer) | Check connections, cable, parameter "A0" in the "Heating circuit" group and remote control settings . For wireless remote controls: check connection, place remote control close to the boiler. |
BE | Control mode without remote control | Communication error, Vitotrol remote control, heating circuit 3 (with mixer) | Check connections, cable, parameter "A0" in the "Heating circuit" group and remote control settings . For wireless remote controls: check connection, place remote control close to the boiler. |
BF | Control mode | Incorrect LON communication module | Replace LON communication module. |
C1 | Control mode | Communication error, EA1 extension | Check connections. |
C2 | Control mode | Communication error, solar control module or Vitosolic | Check solar control module or Vitosolic. |
C3 | Control mode | Communication error, AM1 extension | Check connections. |
C4 | Control mode | Communication error, OpenTherm extension | Check OpenTherm extension. |
C5 | Control mode, max. pump speed | Communication error, internal variable speed pump | Check setting of parameter "30" in "Boiler" group. |
CD | Control mode | Communication error, Vitocom 100 (KM-BUS) | Check connections, Vitocom 100 and parameter "95" in "General" group. |
CF | Control mode | Communication error, communication module | Replace communication module. |
D3 | Burner in a fault state or blocked. | Communication error, fan unit | Check the connecting cable to the fan unit. Press reset button R. If the fault recurs, replace the fan unit. |
D4 | Control mode Burner is operating with a limited modulation range. | No air flow detected in fan unit. | Check the mass flow sensor at the fan unit. Check the flue system for flue gas back pressure. |
D5 | Burner in a fault state. | Fan blocked | Press reset button R. Check free movement of the impeller. Replace the fan unit if required. |
D6 | Control mode | Input DE1 at EA1 extension reports a fault. | Remedy fault at appliance concerned. |
D7 | Control mode | Input DE2 at EA1 extension reports a fault. | Remedy fault at appliance concerned. |
D8 | Control mode | Input DE3 at EA1 extension reports a fault. | Remedy fault at appliance concerned. |
DA | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 1 (without mixer) | Check room temperature sensor, heating circuit 1. External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
DB | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 2 (with mixer) | Check room temperature sensor, heating circuit 2. External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
DC | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 3 (with mixer) | Check room temperature sensor, heating circuit 3. External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
DD | Control mode without room influence | Lead break, room temperature sensor, heating circuit 1 (without mixer) | Check room temperature sensor, heating circuit 1 and remote control settings . External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
DE | Control mode without room influence | Lead break, room temperature sensor, heating circuit 2 (with mixer) | Check room temperature sensor, heating circuit 2 and remote control settings. External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
DF | Control mode without room influence | Lead break, room temperature sensor, heating circuit 3 (with mixer) | Check room temperature sensor, heating circuit 3 and remote control settings ). External room temperature sensor for Vitotrol 300 or integrated sensor for Vitotrol 200/300 |
E0 | Control mode | External LON subscriber error | Check connections and LON subscribers. |
E2 | Burner in a fault state | No calibration as flow rate too low | Ensure adequate heat transfer. Press reset button R. |
E3 | Burner in a fault state | Heat transfer too low during calibration Temperature limiter has shut down. | Ensure adequate heat transfer. Press reset button R. |
E4 | Burner blocked | 24 V power supply fault | Replace control unit. |
E5 | Burner blocked | Flame amplifier fault | Replace control unit. |
E8 | Burner in a fault state | Ionisation current lies out- side the permissible range | Check gas supply (gas pressure and gas flow switch), gas train and connecting cable. Check assignment of gas type. Check ionisation electrode: ■ Distance to burner gauze assembly (see page 42) ■ Electrode soiled Press reset button R. |
EB | Burner in a fault state | Repeated flame loss or deactivation during calibration | 1. Check system for excessive temperature. If fault F1 or F2 is present, ensure there is adequate heat transfer. Press reset button R. 2. Check system for condensate backup. Note To prevent water damage, detach fan unit before removing the burner. Remove the condensate back- up. Press reset button R. 3. Check ionisation electrode for contamination. Check gap between ionisation electrode and burner gauze assembly (see page 42). Press reset button R. 4. Check flue system; remove flue gas recirculation if required. Press reset button R. |
EC | Burner in a fault state | Parameter error during calibration | Press reset button R. or Replace boiler coding card and press reset button R. |
ED | Burner in a fault state | Internal fault | Replace control unit. |
EE | Burner in a fault state | Flame signal at burner start not present or insufficient. | ■ Check gas supply (gas pressure and gas flow switch). ■ Check gas train. ■ Check system for condensate backup. Note To prevent water damage, detach fan unit before removing the burner. ■ Check ionisation electrode and connecting cable. Check ignition: ■ Connecting cables to ignition module and ignition electrode ■ Ignition electrode gap and soiling (see page 42). Press reset button R. |
EF | Burner in a fault state | Flame is lost immediately after it has built (during safety time). | Check gas supply (gas pressure and gas flow switch). Check balanced flue system for flue gas recirculation. Check ionisation electrode (replace if required): ■ Distance to burner gauze assembly (see page 42) ■ Electrode soiled Press reset button R. |
F0 | Burner blocked | Internal fault | Replace control unit. |
F1 | Burner in a fault state | Flue gas temperature limiter has responded. | Check heating system fill level. Vent the system. When the flue system has cooled down, press reset button R. |
F2 | Burner in a fault state | Temperature limiter has responded. | Check heating system fill level. Check circulation pump. Vent the system. Check temperature limiter and connecting cables. Press reset button R. |
F3 | Burner in a fault state | Flame signal is already present at burner start. | Check ionisation electrode and connecting cable. Check system for condensate backup. Note To prevent water damage, detach fan unit before removing the burner. Press reset button R. |
F8 | Burner in a fault state | Fuel valve or modulation valve will not close. | Check the gas train and replace if required. Press reset button R. |
F9 | Burner in a fault state | Fan speed too low | Check fan, fan connecting cables and fan power supply. Press reset button R. |
FA | Burner in a fault state | Fan idle state or set speed not reached | Check fan, check connecting cables to fan. Press reset button R. |
FC | Burner in a fault state | Fan unit faulty. | Check fan unit, replace if required. Press reset button R. |
Fd | Burner in a fault state and additional fault B7 is displayed. | Boiler coding card missing. | Insert the boiler coding card. Press reset button R. Replace control unit if fault persists. |
Fd | Burner in a fault state | Burner control unit fault | Check ignition electrode, ionisation electrode and connecting cables. Check whether a strong interference (EMC) field exists near the appliance. Press reset button R. If the fault occurs sporadically, replace the coding card. Replace control unit if fault is permanent. |
FE | Burner blocked or in a fault state | Boiler coding card or main PCB faulty, or incorrect boiler coding card | Press reset button R. If the fault persists, check the boiler coding card and replace boiler coding card or control unit if necessary. |
FF | Burner blocked or in a fault state | Internal fault or reset button R blocked. | Restart the appliance. Replace the control unit if the appliance will not restart. |
Displayed fault code | Const. | Weath.- comp. | System characteristics | Cause | Measures |
---|---|---|---|---|---|
10 | X | X | Regulates as if the outside temperature were 0 °C | Short circuit, outside temperature sensor | Check the outside temperature sensor. |
18 | X | X | Regulates as if the outside temperature were 0 °C | Lead break, outside temperature sensor | Check the outside temperature sensor. |
20 | X | X | Regulates without flow temperature sensor (low loss header) | Short circuit, system flow temperature sensor | Check the low loss header sensor. |
28 | X | X | Regulates without flow temperature sensor (low loss header) | Lead break, system flow temperature sensor | Check the low loss header sensor. |
30 | X | X | Burner blocked | Short circuit, boiler water temperature sensor | Check the boiler water temperature sensor . |
38 | X | X | Burner blocked | Lead break, boiler water temperature sensor | Check the boiler water temperature sensor . |
40 | X | Mixer closes | Short circuit, flow temperature sensor, heating circuit 2 (with mixer) | Check flow temperature sensor | |
44 | X | Mixer closes | Short circuit, flow temperature sensor, heating circuit 3 (with mixer) | Check flow temperature sensor | |
48 | X | Mixer closes | Lead break, flow temperature sensor, heating circuit 2 (with mixer) | Check flow temperature sensor | |
4C | X | Mixer closes | Lead break, flow temperature sensor, heating circuit 3 (with mixer) | Check flow temperature sensor | |
50 | X | X | No DHW heating | Short circuit, cylinder temperature sensor | Check sensors |
51 | X | X | No DHW heating | Short circuit, outlet temperature sensor | Check sensors |
58 | X | X | No DHW heating | Lead break, cylinder temperature sensor | Check sensors |
59 | X | X | No DHW heating | Lead break, outlet temperature sensor | Check sensors |
A7 | X | Control mode as per delivered condition | Programming unit faulty | Replace programming unit | |
A9 | X | The burner operates at its lower output if a heating circuit with mixer is connected. The burner is blocked if only one heating circuit without mixer is connected. | Internal circulation pump blocked | Check the circulation pump | |
b0 | X | X | Burner blocked | Short circuit, flue gas temperature sensor | Check the flue gas temperature sensor |
b1 | X | X | Control mode as per delivered condition | Communication error, programming unit | Check connections and replace the programming unit if required |
b5 | X | X | Control mode as per delivered condition | Internal fault | Replace the control unit |
b7 | X | X | Burner blocked | Boiler coding card faulty | Plug in boiler coding card or replace, if faulty |
b8 | X | X | Burner blocked | Lead break, flue gas temperature sensor | Check the flue gas temperature sensor |
bA | X | Mixer regulates to a flow temperature of 20 °C | Communication error, extension kit for heating circuit 2 (with mixer) | Check extension kit connections and code | |
bb | X | Mixer regulates to a flow temperature of 20 °C | Communication error, extension kit for heating circuit 3 (with mixer) | Check extension kit connections and code | |
bC | X | Control mode without remote control | Communication error, remote control Vitotrol heating circuit 1 (without mixer) | Check connections, lead, coding address "A0" and remote control settings | |
bd | X | Control mode without remote control | Communication error, remote control Vitotrol heating circuit 2 (with mixer) | Check connections, lead, coding address "A0" and remote control settings | |
bE | X | Control mode without remote control | Communication error, remote control Vitotrol heating circuit 3 (with mixer) | Check connections, lead, coding address "A0" and remote control settings | |
bF | X | Control mode | Incorrect LON communication module | Replace the LON communication module | |
C1 | X | X | Control mode | Communication error extension EA1 | Check electrical connections |
C3 | X | X | Control mode | Extension AM1 communication error | Check electrical connections |
C4 | X | X | Control mode | Communication error, Open Thermextension | Check Open Therm extension |
C5 | X | X | Control mode, max. pump speed | Communication error, variable speed internal pump | Check the setting of coding address "30" |
C6 | X | Control mode, max. pump speed | Communication error, external variable speed heating circuit pump, heating circuit 2 (with mixer) | Check setting of coding address "E5" | |
C7 | X | X | Control mode, max. pump speed | Communication error, external variable speed heating circuit pump, heating circuit 1 (without mixer) | Check setting of coding address "E5" |
C8 | X | Control mode, max. pump speed | Communication error, external variable speed heating circuit pump, heating circuit 3 (with mixer) | Check setting of coding address "E5" | |
Cd | X | X | Control mode | Communication error, Vitocom 100 (KM BUS) | Check connections, Vitocom 100 and coding address "95" |
CE | X | X | Control mode | Communication error, ext. extension | Check electrical connections |
CF | X | Control mode | Communication error, LON communication module | Replace the LON communication module |
|
d6 | X | X | Control mode | Input DE1 reports a fault at extension EA1 | Remove fault at the appliance concerned |
d7 | X | X | Control mode | Input DE2 reports a fault at extension EA1 | Remove fault at the appliance concerned |
d8 | X | X | Control mode | Input DE3 reports a fault at extension EA1 | Remove fault at the appliance concerned |
dA | X | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 1 (without mixer) | Check room temperature sensor, heating circuit 1 | |
db | X | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 2 (with mixer) | Check room temperature sensor, heating circuit 2 | |
dC | X | Control mode without room influence | Short circuit, room temperature sensor, heating circuit 3 (with mixer) | Check room temperature sensor, heating circuit 3 | |
dd | X | Control mode without room influence | Lead break, room temperature sensor, heating circuit 1 (without mixer) | Check room temperature sensor for heating circuit 1 and remote control settings | |
dE | X | Control mode without room influence | Lead break, room temperature sensor, heating circuit 2 (with mixer) | Check room temperature sensor for heating circuit 2 and remote control settings | |
dF | X | Control mode without room influence | Lead break, room temperature sensor, heating circuit 3 (with mixer) | Check room temperature sensor for heating circuit 3 and remote control settings | |
E0 | X | Control mode | Fault external LON subscriber | Check connections and LON subscribers | |
E4 | X | X | Burner blocked | Fault, supply voltage 24 V | Replace the control unit. |
E5 | X | X | Burner blocked | Fault, flame amplifier | Replace the control unit. |
E8 | X | X | Burner in a fault state | The ionisation current lies outside the permissible range | Check the ionisation electrode and cable. Press reset button R. |
EA | X | X | Burner in a fault state | The ionisation current lies outside the permissible range during calibration | Check the ionisation electrode and cable. Press reset button R. |
Eb | X | X | Burner in a fault state | Heat draw-off repeatedly too low during calibration | Initiate a heat draw-off. Switch the boiler OFF and ON again. Press reset button R. |
EC | X | X | Burner in a fault state | Parameter fault during calibration | Press reset button R or replace boiler coding card and press reset button R. |
Ed | X | X | Burner in a fault state | Internal fault | Replace the control unit. |
EE | X | X | Burner in a fault state | Flame signal is not present or too weak at burner start | Check the ionisation electrode and connecting cable, measure the ionisation current, check the gas supply (gas pressure and gas flow limiter), check the gas train, ignition, ignition module, ignition electrodes and the condensate drain. Press reset button R. |
EF | X | X | Burner in a fault state | Flame is lost after flame has built. | Check the gas supply (gas pressure and gas flow limiter), check the flue gas/ventilation air system for flue gas recirculation, check the ionisation electrode (replace if required). Press reset button R. |
F0 | X | X | Burner blocked | Internal fault | Replace the control unit. |
F1 | X | X | Burner in a fault state | Flue gas temperature limiter has responded | Check the heating system fill level. Vent the system. Press reset button R after the flue system has cooled down. |
F2 | X | X | Burner in a fault state | The temperature limiter has responded | Check the heating system fill level. Check the circulation pump. Vent the system. Check the temperature limiter and connecting cables Press reset button R. |
F3 | X | X | Burner in a fault state | Flame signal is already present at burner start | Check the ionisation electrode and connecting cable. Press reset button R. |
F8 | X | X | Burner in a fault state | The fuel valve closes too late | Check the gas train. Check both control paths. Press reset button R. |
F9 | X | X | Burner in a fault state | Fan speed too low during burner start | Check the fan, the fan connecting cables and power supply; check the fan control. Press reset button R. |
FA | X | X | Burner in a fault state | Fan not at standsill | Check the fan, fan connecting cables and fan control. Press reset button |
FC | X | X | Burner in a fault state | Gas train faulty or faulty modulation valve control or flue gas path blocked | Check the gas train. Check the flue gas system.. Press reset button R. |
Fd | X | X | Burner in a fault state | Fault, combustion controller | Check ignition electrodes and connecting cables Check whether a strong interference (EMC) field exists near the appliance. Press reset button R. Replace control unit if the fault persists. |
FE | X | X | Burner blocked or in a fault state | Boiler coding card or main PCB faulty | Press reset button R. Replace boiler coding card or control unit if the fault persists. |
FF | X | X | Burner blocked or in a fault state | Internal fault or reset button R blocked | Start the appliance again. Replace the control unit if the appliance will not restart. |
Boilerhut Limited
UK Head Office
Above Willis Systems
Lamby Industrial Park
Wentloog Avenue
Cardiff
CF3 2EX