- Logical fault finding procedure
- Status codes
- Diagnostic codes
- Fault codes
- Fault memory
- Test programs
1-Logical Fault Finding Procedure:
These checks must be carried out before attempting to use the fault finding guide.
- Carry out electrical safety checks.
- Check that the external electricity supply to the boiler is on, and a supply of 230 V~ is present between boiler terminals ‘L’ and ‘N’.
- Check that the gas supply to the boiler is on, that it has been correctly purged and that an inlet pressure of 20 mbar is available at the gas valve. (See section ‘Gas Supply’).
- Ensure the heating system is full of water and charged to between 1 and 1.5 bar. If not, refill and vent the system. (See section ‘Filling the heating system’). Ensure boiler flow and return service valves are open.
- Check that the main on/off control is set to the ‘on’ position.
- Set the central heating temperature to maximum.
- Set the domestic hot water temperature to maximum (combination boilers only).
- Check that all external controls are on and calling for heat (if no external controls are fitted, boiler terminals 3 and 4 must be linked). Check that the boiler anti-cycling economiser is not engaged.
The status codes that you can see on the display provides information about the current operating condition of the appliance. The display of the status codes can be called as follows:
Press the “i” key. The display shows the status code, e.g. S.04 for “Burner mode – Heating”.
The display of the status codes can be cancelled as follows:
- Press the “i” key or
- Do not press any key for about 4 minutes. The current heating flow temperature appears in the display again.
|All models (heating mode)|
|S.00||No heat demand|
|S.02||Water pump running|
|S.05||Fan and pump running|
|S.06||Fan over run|
|S.07||Pump over run|
|S.08||Anti cycling mode|
|ecoTEC combination boilers only (Domestic hot water mode)|
|S.10||Hot water demand|
|S.15||Fan and pump running|
|S.16||Fan over run|
|S.17||Pump over run|
|ecoTEC combination boilers only (warm start)|
|S.25||Fan and water pump running|
|S.26||Fan over run|
|S.27||Pump over run|
|S.28||Anti cycling mode|
|S.30||No heating demand from external controls|
|S.31||Central heating thermostat knob turned off or no heat demand by the eBUS control unit|
|S.32||Heat exchanger antifreeze active, as fan speed variation is too high. Appliance is within the waiting time of the operation block function|
|S.34||Antifrost mode active|
|S.36||No heating demand from low voltage controls|
|S.42||Response from accessory modul or defective condensate pump is blocking burner operation|
|S.53||Appliance is within the waiting period of the operation block function due to water shortage|
|S.54||Appliance is within the waiting period of the operation block function due to water shortage|
|S.76||Appliance is within the waiting period of the operation block function due to water shortage|
|S.96||Return-sensor check is running, demand|
|S.97||Waterpressure sensor check is running, demand|
|S.98||Flow-/Return-sensor check is running, demand|
In the diagnostic mode, you can change certain parameters or display more information. The diagnostic information is divided into two diagnostic levels. The second diagnostic level can be reached only after entering a password.
Access to the second diagnostic level must be used exclusively by a qualified technician.
First Diagnostic level
- Press the “i” and “+” keys simultaneously. The display shows “d.00”.
- Use the “+” or “–” keys to scroll through the desired diagnostic numbers of the first diagnostic level
- Press the “i” key. The display shows the relevant diagnostic information.
- If necessary, use the “+” or “–” keys to change the value
- Save the new value by holding down the “i” key for approx. 5 seconds until the display no longer flashes.
You can end the diagnostic mode as follows:
- Press the “i” and “+” keys simultaneously.
- Do not press any key for approx. 4 minutes.
The current heating flow temperature appears in the display again.
Second diagnostic level
- As described above in the first diagnostic level, scroll through the diagnostic number d.97.
- Change the displayed value to 17 (password) and press the “i” button.
You are now in the second diagnostic level where all information from the first diagnostic level and the second diagnostic level is displayed. Scrolling and changing values and exiting the diagnostic mode is done as described in the first diagnostic level.
Note: After exiting the second diagnostic level, if you press “i” and “+” within 4 minutes, you will directly reach the second diagnostic level without having to enter the password again.
|Display||Meaning||Display value/adjustable value|
|d.00||Heating part load||Adjustable heating part load in kW|
|d.01||Water pump over run time for heating mode||1 - 60 min (factory setting: 5 min)|
|d.02||Max. burner anti cycling period at 20 °C Flow temperature||2 - 60 min (factory setting: 20 min)|
|d.03||Hot water flow temperature reading (combination boiler only)||in °C|
|d.04||Current temperature for warm start sensor||1 to 100 = on, 0 = off|
|d.05||Flow temperature target value or return target value when return regulation is set.||In °C, min. 30 °C and max. the value set in d.71 Limited by the eBUS controller|
|d.06||Hot water temperature target value||in °C, 35 to 65 °C|
|d.07||Warm start temperature target value. Storage temperature target value||in °C, 40 to 65 °C. in °C, 15 °C for left stop, then 40 to 70 °C|
|d.08||External controls heat demand||0 = no heat request (open) 1 = heat request (closed)|
|d.09||Flow target temperature from external analogue regulator to terminal 7-8-9/eBUS||in °C, minimum from ext. eBUS target value and target value terminal 7|
|d.10||Status internal heating pump||1, 2 = on, 0 = off|
|d.11||Status external heating pump||1 to 100 = on, 0 = off|
|d.13||Hot water circulation pump||1 to 100 = on, 0 = off|
|d.22||Hot water demand||1 = on, 0 = off|
|d.23||Summer/Winter function||1 = Winter, 0 = Summer|
|d.25||Hot water activation via eBUS Control||1 = yes, 0 = no|
|d.40||Flow temperature||Actual value in °C|
|d.41||Return temperature||Actual value in °C|
|d.47||Outside temperature||Actual value in °C|
|d.67||Remaining burner anti cycling time||in min|
|d.76||Appliance variant||00 to 99|
|d.90||Digital regulator status||1 = identified, 0 = unidentified|
|d.91||DCF status with connected external probe with DCF77 receiver||0 = no reception, 1 = reception, 2 = synchronised, 3 = valid|
|d.97||Activation of the second diagnostic level||Password: 17|
|d.17||Heating flow/return regulation changeover||0 = flow, 1 = return|
|d.18||Pump mode||0 = return, 1 = nonstop, 2 = winter|
|d.19||Only in ecoTEC plus: Operating modes of the two-stage heating pump||0 = Burner mode = 2, flow/return = 1 1 = Heating + flow =1, service water = 2 2 = Like 1, but speed in heating mode dependent on heating partial load (default setting) 3 = Always stage 2|
|d.27||Switching accessory relay 1 in the accessory module||1 = Circulation pump (default) 2 = Ext. pump 3 = Storage charging pump 4 = Flue gas flap/extractor hood 5 = External gas valve 6 = External error message|
|d.28||Switching accessory relay 2 in the accessory module||1 = Circulation pump 2 = Ext. pump (default) 3 = Storage charging pump 4 = Flue gas flap/extractor hood 5 = External gas valve 6 = External error message|
|d.30||Control signal for both gas valves||1 = on, 0 = off|
|d.33||Fan speed target value||in rpm/10|
|d.34||Fan speed actual value||in rpm/10|
|d.35||Position of diverter valve||0 = Heating; 1 = Hot water; 2 = Centre position|
|d.36||Hot water flow sensor||in l/min|
|d.44||Ionisation current||Actual value [10nA]|
|d.50||Offset for minimum speed||in rpm/10, adjustment range: 0 to 250|
|d.51||Offset for maximum speed||in rpm/10, adjustment range: -99 to -0|
|d.60||Number of safety temperature limiter cut offs||Quantity|
|d.61||Number of lock outs||Number of unsuccessful ignitions in the last attempt|
|d.64||Average ignition time||in seconds|
|d.65||Maximum ignition time||in seconds|
|d.68||Unsuccessful ignitions in the first attempt||Quantity|
|d.69||Unsuccessful ignitions in the second attempt||Quantity|
|d.70||Set diverter valve position||0 = Normal mode (factory setting) 1 = Centre position 2 = permanent heating position|
|d.71||Maximum setting of heater control knob||Adjustment range in °C: 40 to 85 (Factory setting: 75)|
|d.72||Pump overrun time after charging an electronically controlled hot water storage||Adjustment range in sec: 0, 10, 20 to 600 Factory setting for 800 series: 80 Factory setting for 600 series: 300|
|d.73||Offset for warm start target value||Adjustment range: -15 K to +5 K|
|d.75||Maximum charging time for a storage without own controller||Adjustment range in min: 20, 21, 22 to 90|
|d.77||Storage partial load||Adjustment range in kW: appliance-specific Factory setting: max. output|
|d.78||Storage charging temperature limit||Adjustment range in °C 55 to 90|
|d.80||Heating operating hours|| in h
|d.81||Water heating operating hours||in h|
|d.82||Cycles in heating mode||Quantity|
|d.83||Cycles in hot water operation||Quantity|
|d.84||Maintenance indicator: Number of hours until the next maintenance||Adjustment range: 0 to 3000 h and “-” Factory setting: “-”|
|d.93||DSN appliance variant setting||Adjustment range: 0 to 99|
|d.96||Factory setting||1 = Resetting adjustable parameters to factory setting|
Fault codes take priority over all other display functions in the event of a system fault occurring. If multiple faults occur, the corresponding fault codes are displayed alternately for about two seconds each.
The fault memory stores details of the ten most recent faults.
- Press the ”i” and ”–” buttons simultaneously.
- Use the ”+” button to scroll back through the list of memorised errors.
To cancel fault error memory display mode, proceed as follows:
- Press the ”i” button below the display or
- Do not touch any key for about four minutes. The display will now revert back to showing the current flow temperature.
|F.00||Flow–NTC open circuit||NTC broken, NTC cable broken, Defective connection at NTC, Defective connection at electronics|
|F.01||Return–NTC open circuit||NTC broken, NTC cable broken, Defective connection at NTC, Defective connection at electronics|
|F.02||Domestic hot water outlet NTC open circuit||NTC-connector not plugged in or loose, NTC defective connector on the electronics not plugged in correctly, cable defective|
|F.10||Flow NTC short circuit||NTC defective,cable/casing shortcut|
|F.11||Return NTC short circuit||NTC defective, cable/casing shortcut|
|F.13||Tank NTC short circuit||NTC defective,short circuit in cable harness, cable/casing shortcut|
|F.20||Safety temperature limiter by NTC activated||Flow-NTC not correctly thermal-connected or defective; appliance does not shut down|
|F.22||Dry fire||Too little water in the appliance, water pressure sensor defective, cable to pump or water sensor defective, pump blocked or defective, pump output too low|
|F.23||Water shortage, temperature difference between flow and return NTC too large||Pump blocked or defective, pump output too low, flow and return NTC interchanged|
|F.24||Water shortage, temperature rise too quick||Pump blocked, insufficient pump output, air in appliance, water pressure too low|
|F.27||Incorrect sensing of flame||Flame detector defective|
|F.28||Appliance does not start: Attempts to ignite during start failed||Faults in the gas supply such as: - Gas meter or gas pressure detector defective - Air in gas - Gas flow pressure too low - Fire protection tap has disengaged Faults in the gas valve, wrong gas setting, igniter (ignition transformer, ignition cable, ignition plug) defective, ionisation current stopped (cable, electrode), faulty earthing in appliance, electronics defective|
|F.29||Flame goes off during operation and subsequent ignition attempts failed||Gas supply temporarily stopped, faulty earthing of appliance|
|F.32||Fan speed variation||Fan blocked, plug not inserted correctly on fan, hall sensor defective, fault in cable harness, electronics defective|
|F.49||eBUS undervoltage||Short circuit on eBUS, overload on eBUS or two power sources on eBUS with different polarity|
|F.61||Gas–valve control defective||Short circuit/earth (ground) leak in cable harness to gas valves, gas valve assembly defective (earth/ground leak from coils), electronic control system defective|
|F.62||Gas valve shutoff delay||Gas valve leaking, electronics defective|
|F.63||EEPROM error||Electronics defective
|F.64||Electronics/NTC fault||Short-circuit in flow or return NTC or electronics defective|
|F.65||Electronics temperature too high||Electronics too hot due to external effect, electronics defective|
|F.70||No valid DSN in display and/or mainboard||Spare part failure display and maiboard interchanged at same time and device specific number not adjusted|
|F.71||Flow NTC reports constant value (stuck at)||Flow NTC is defective|
|F.72||Flow and/or return NTC fault||Flow and/or return NTC is defective (tolerances too big)|
|F.73||Water pressure sensor signal out of range (too low)||Cable to water pressure sensor is broken or has a short-circuit at 0 V or water pressure sensor defective|
|F.74||Water pressure sensor signal out of range (too high)||Cable to water pressure sensor has a short-circuit at 5 V / 24 V or internal fault in water pressure sensor|
|F.75||No pressure rise was detected on turning on the pump||Water pressure sensor or/and pump defective Too little water in appliance; check adjustable by-pass; connect external expension vessel to return|
|F.76||Overheating protection on primary heat exchanger triggered||Cable or cable connection of fuse in the primary heat exchanger defective, or primary heat exchanger defective|
|F.77||condensate pump or feedback of accessorie blocks heating||condensate pump defective or flume flap feedback triggered|
|F.78||wrong configuration with accessory||link box VR65 connected to combination boiler|
|con||no communication to mainboard||connection error display mainboard|
Special functions can be triggered on the appliances by activating various test programs. These programs are given in detail in the table.
- The test programs P.0 to P.6 will be started when “Power ON” is turned on and the “+” key is pressed for 5 s. The display shows “P.0”.
- Press the “+” key to start counting the test number upwards.
- Press the “i” to operate the appliance now and to start the test program.
- Press “i” and “+” simultaneously to exit the test programs. You can also exit the test programs by not pressing any key for 15 minutes.
|P.0||Bleeding test program. The heating circuit and hot water circuit (combination boiler only) is bled via the automatic air vent (the cap on the automatic air vent must be loosened).|
|P.1||Test program where the appliance is operated in full load after successful ignition|
|P.2||Test program where the appliance is operated with minimum gas volume (ignition gas volume) after successful ignition|
|P.5||Test program for the safety temperature limit check; appliance heats up by by-passing a regulating shutdown through the flow regulator until the shutoff temperature of 97 °C is achieved.|
|P.6||Filling test program. The diverter valve moves to the centre position|