When your boiler isn’t working as it should, then the first place to look is on the control panel screen.
This is where there your system will display an error code which will give you an indication of what the problem might be. Don’t be stressing about the new boiler cost just yet.

Each boiler company has a set of error codes for their boilers, and in this guide, we’re going to look at those in place for Vaillant central heating boilers. First off, we’ll take a look at the most common error codes and then we’ll provide you with a complete list of all the ones in use by this manufacturer.
Diagnosing Vaillant Fault Codes & Error Messages
As with most types of boilers, some of the issues will need a professional technician to visit. However, others are quick and easy to sort out, meaning that you’ll have hot water and heating in no time at all instead of a new boiler installation.
If having no heating or hot water is a big worry for you and your family, then boiler cover can be the perfect solution.
A small monthly payment means that you can avoid hefty bills should your system need professional attention. They can even put money towards your next boiler replacement.
[get-a-quote]How to fix an F22 error code
Now, as error codes go, the Vaillant F22 is generally not too bad. This is because this code appears when the water pressure in your boiler has become too low.
As your system needs a pre-set level of pressure to operate, the system will lock out when it gets too low. This then results in Vaillant boiler F22 error.Â
Water is added through the filling loop on your boiler while keeping an eye on the pressure gauge; while low pressure causes problems, so does high pressure!
If you’re not sure where the filling loop is, check out your manual for more information. Can’t find your manual? No problem, you can download a copy from the Vaillant website
This is a common problem with even the best combi boilers and best system boilers, so we have a guide for you that focuses just on this issue which you can find here.

How to fix an F29 fault code
The Vaillant F29 error code appears when the flame in the boiler hasn’t lit.
Without this then the system is unable to heat the water. There are several different reasons as to why this might happen, and they include:
- Issues with the gas supply
- The burner is clogged up with debris
- The condensate pipe has become frozen
- The flue is faulty
- Problems with the ignition lead.
While many of these issues do need a visit from an engineer, there are two things you could try.
First of all, check your gas supply by seeing if other gas appliances are working. Then, if the weather has been below zero, check the condensate pipe to see if it has frozen up.
If there is a build-up of ice, this can be melted by pouring warm water over the pipe.
How to fix an F61 fault code
The Vaillant f61 fault code means that there is a problem with the gas valve. Because this could be a potentially dangerous situation, your boiler then locks the system to prevent further use until the issue has been resolved.
Fixing the F61 Vaillant error code will mean calling out an engineer. They will usually replace the valve, which may become seized or stuck simply through use.
[get-a-quote]How to fix an F24 error code
The F24 Vaillant error code is caused by a lack of water or none at all, circulating around the system. There are several reasons as to why this might happen, including:

- Problems with the pump
- The isolation valve is turned to closed
- The boiler or heating system having an airlock
- Debris in the heat exchanger
While most of these will need an engineer’s help, you can check the isolation valve to ensure it’s in the open position.
How to fix an F62 error code
Just a with the F61 code, the F62 Vaillant code also means a problem with the gas valve. This will then mean that you’re likely to need the assistance of an engineer.
All Vaillant Boiler Error Codes
While there can be variations in the error codes between different Vaillant boilers, we’re detailed some of the most common one’s for you in the table below.
| Vaillant Boiler Error Code | Problem |
| F.00 / F.0 | Interruption of the flow temperature sensor |
| F.01 / F.1 | Interruption of the return temperature sensor |
| F.10 | Short circuit of the flow NTC |
| F.11 | Short circuit of the return NTC |
| F.20 | Temperature limiter safety switch activated |
| F.22 | Low-pressure safety switch activated |
| F.23 | Temperature difference too great, safety switch activated |
| F.24 | Temperature increasing too rapidly, safety switch activated |
| F.25 | Flue gas temperature too high, safety switch activated |
| F.26 | Gas valve error |
| F.27 | Flame simulation, safety switch activated |
| F.28 | Ignition not started |
| F.29 | Re-ignition failed |
| F.32 | Problem with fan |
| F.49 | Potential short circuit due to eBUS error |
| F.61 | Gas valve regulation problem |
| F.62 | Gas valve problem due to switch-off delay |
| F.63 | Problem with the EEPROM |
| F.64 | Problem with the electronics / NTC |
| F.65 | Overheating of the electronic temperature |
| F.67 | Issue with the Electronics flame signal |
| F.00 / F.0 | Interruption of the flow temperature sensor |
| F.01 / F.1 | Interruption of the return temperature sensor |
| F.10 | Short circuit of the low NTC |
| F.11 | Short circuit of the return NTC |
Summary
Boiler problems can be stressful. However, with our guide, you’ll be able to establish what the issue is and, in some cases, fix it without needing a callout. For more help, have a look at our definitive guide to boiler problems.
All boilers reach a point where it just doesn’t become viable to fix them one more time. This is when our fixed price boiler quote can be the perfect solution.
Just answer a few questions about your heating needs, and you’ll immediately see our great boiler offers along with a fixed price quote.
You’ll soon be up and running with a nice warm home and endless hot water!
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