Zanussi Combi Boiler Error Codes Listed below are the common Zanussi fault codes as described by the boiler manufacturer along with a possible cause. In this guide, we’ll cover common Zanussi boiler problems, whether you need a heating engineer and how to fix them if you don’t.
Zanussi Combi Boiler Error Code Solutions
| Fault Code | System Behaviour |
| C0 | Boiler chip card (BCC) activation fault |
| C2 | Boiler chip card (BCC) fault |
| F1 | Low water pressure |
| F2 | Flame loss |
| F3 | Fan fault |
| F4 | Flow thermistor |
| F5 | Return thermistor |
| F6 | Outside sensor failure |
| F7 | Low mains voltage |
| F9 | Un-configured printed circuit board (PCB) |
| L1 | Flow temperature overheat or no water flow |
| L2 | Flame loss |
| L5 | 5 boiler resets in 15 minutes |
| L6 | False flame lockout |
Boiler keeps turning itself off
If your Zanussi boiler keeps turning itself off, then this is likely to be due to a lack of water flow. This could be due to closed valves, air caught in the system or a broken pump. Try bleeding your radiators, and if lots of air comes out then you’ll know there was too much air in the system.
Leaking
If your boiler starts leaking, it could be quite a serious problem. Even the tiniest of leaks could get much worse fairly quickly. A leak suggests that an internal component like a seal or valve is broken and can then lead to corrosion and rust. It could even cause electrical components to short circuit.
3. False flame lockout (L6)
A false flame lockout is represented by the error code L6 on your boiler’s screen. Try resetting your boiler, if this doesn’t do the trick then the flame detection electrode may need replacing.
4. Low boiler pressure (F1)
To check the pressure of your boiler, just take a look at the pressure gauge. If you see anything below 1, you may have an issue. Find out more with our guide to low boiler pressure.
5. Radiators not getting hot
If you’re finding that none or just some of your radiators are getting hot, this is likely to be a result of air build-up in the system and unequal distribution of heat. To remove this air, you will need to bleed the radiators.
How to bleed a radiator
Bleeding a radiator is fairly straightforward and doesn’t require an engineer (unless you’d prefer an engineer to carry out the task). Use our guide to bleeding radiators to take you through the process.