View Cointra faults by model and generation
If your Cointra Superlative Condens 25C will not start, locks out or displays F37, start with the full code. This guide distinguishes ignition, overheating, pressure and sensor faults, using the manufacturer's table and useful details for describing the problem.
Cointra Superlative Condens 25C symptoms and faults
A01: burner does not igniteA01 identifies a burner ignition fault.
Possible causes include a lack of gas or air present in the gas line, the flame-detection/ignition electrode, gas valve, insufficient gas pressure and a blocked siphon.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), table 8 · page 8.
A03: overtemperature protectionA03 appears when overtemperature protection is activated.
Diagnosis distinguishes the heating sensor, insufficient water circulation and air in the system.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), table 8 · page 8.
F37: heating-circuit pressureF37 indicates incorrect water pressure in the heating circuit.
This may mean the pressure is too low or the water pressure switch is disconnected or faulty. The manual for this 25C specifies a cold fill pressure of about 1 bar; this is the reference for this model, not a universal value.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), hydraulic adjustment and table 8 · pages 4, 8.
F11: return sensorF11 corresponds to the return sensor.
Causes to distinguish are the sensor itself and broken or short-circuited wiring; this is not a hot-water sensor warning.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), table 8 · pages 8, 9.
F13: flue-gas sensorF13 corresponds to a flue-gas sensor fault.
Checks cover the sensor and its wiring; the code alone does not mean that the flue duct is blocked.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), table 8 · pages 8, 9.
A lockout code or temporary F warningA codes correspond to permanent lockouts and F codes to transient faults.
Record the letter, every digit and whether the warning disappears once conditions return to normal; also note whether DHW, heating or both are unavailable.
Source: Cointra Superlative Condens 25 C, 3541H270 Rev. 00 (11/2015), introduction to faults and table 8; type identification on cover · pages 1, 8.
What to observe: identify the full model, record the panel indication and distinguish whether hot water, heating or both are failing. The indication guides the checks; the diagnosis determines the repair.
Code meanings
| Code | Meaning given by Cointra |
|---|---|
| A01 | The burner does not ignite |
| A02 | Flame signal present with burner off |
| A03 | Overtemperature protection activated |
| A04 | Flue outlet safety device activated |
| A05 | Fan protection activated |
| A06 | No flame after ignition, 6 times in 4 minutes |
| A23 | Control board parameter fault |
| A24 | Control board parameter fault |
| A26 | Control board parameter fault |
| A41 | Sensor position |
| A42 | Heating sensor fault |
| A61 | ABM03B control unit fault |
| A62 | No communication between the control unit and gas valve |
| A63 | ABM03B control unit fault |
| A65 | ABM03B control unit fault |
| F07 | High flue gas temperature |
| F10 | Flow sensor 1 fault |
| F11 | Return sensor anomaly |
| F12 | Domestic hot water sensor anomaly |
| F13 | Flue sensor anomaly |
| F14 | Flow sensor 2 fault |
| F15 | Fan fault |
| F20 | Control board parameter fault |
| F21 | Control board parameter fault |
| F34 | Supply voltage below 170 V |
| F35 | Abnormal mains frequency |
| F37 | Incorrect water pressure in the system |
| F39 | Outdoor sensor fault |
| F40 | Control board parameter fault |
| F43 | Heat exchanger protection activated |
| F47 | Control board parameter fault |
| F52 | Heating sensor fault |
| F64 | ABM03B control unit fault |
| F66 | ABM03B control unit fault |
The list corresponds to table 8 of the cited manual (pp. 8–9). If the display shows a code that is not listed here, check the appliance’s full model and manual revision; do not apply explanations from another range or version.
What to do when a code appears
Record the exact code and the model shown on the rating plate. Consult the manual for that variant. Do not open the boiler or handle electrical connections, electrodes, gas or internal components. If the fault persists or requires intervention, contact a qualified professional.
Enquire about repairing a Cointra boiler
Frequently asked questions
The manual says that the burner does not ignite. It lists several possible causes, from the supply and ignition to the valve, gas pressure or siphon; diagnosis is needed to distinguish them.
No. Low pressure is one possibility, but the table also lists a disconnected or faulty water pressure switch. The visible reading helps guide the check; the code alone does not identify the cause.
No. The manual associates F11 with a return-sensor fault and lists the sensor or shorted/broken wiring as possibilities. The circuit must be checked before deciding to replace a part.
Not according to the description of F13 in table 8: it indicates a flue-gas sensor fault and lists the sensor or its wiring. Flue and safety checks should be carried out by a professional.
Manual and spare parts
Consult the official Cointra manual (3541H270, Rev. 00).
Cointra Superlative Condens 25C
Document editing
Superlative Condens 25C document. Do not extend its application to other variants due to name similarity.
The PCBs and the extractors are general catalogue categories. Their links do not confirm that a part is compatible with this boiler or corresponds to the displayed code; check the reference against the diagnosis and the appliance’s rating plate.
If your appliance is a Superlative Plus, consult its specific guide: Cointra Superlative Plus 24 C and 28 C. This Condens 25 C table does not replace the documentation for another range.