Worcester Bosch boilers are reliable, but they still throw the odd fault code. The F0 238 is one of them. This page explains what it means, what tends to cause it, and the checks you can safely do before calling an engineer.
If your boiler is showing a different code, you can look up other Worcester Bosch fault codes to see what it means.
- Guide Content
- » What the F0 238 error code means
- » What causes an F0 238 error code
- - Faulty gas valve unit
- - Gas valve leak
- - Control box fault or loose connection
- » How to troubleshoot an F0 238 error code
- - Check the boiler pressure
- - Check your gas supply
- - Call a Gas Safe engineer
- » Get professional help
What the F0 238 error code means
The F0 238 points to a gas valve or control box fault, usually around the gas valve coils. Those coils control the flow of gas into the boiler. When they fail or play up, the boiler can’t register a flame and locks out, showing F0 238 on the display.
In short: the boiler isn’t detecting a flame, so it shuts down on safety grounds.
What causes an F0 238 error code
A few things commonly trigger it.
Faulty gas valve unit
The gas valve can wear out or fail over time. When it does, it stops feeding gas correctly and the boiler flags the F0 238.
Gas valve leak
A leak in the gas valve drops the pressure and can bring up the same code. Gas leaks are a safety risk and need looking at straight away by a Gas Safe engineer.
Control box fault or loose connection
The control box handles communication between the gas valve coils and the boiler. A faulty box, or just a loose connection, can stop things working and trigger the code.
Pinning down which of these it is helps an engineer fix it faster. If you’re not sure, don’t guess — anything involving the gas valve or control box is a job for a professional.
How to troubleshoot an F0 238 error code
There are a couple of safe checks you can do yourself before booking an engineer.
Check the boiler pressure
Look at the pressure gauge. It should sit between 1 and 1.5 bar when the boiler is cold. Low pressure can cause fault codes. If it’s low, your boiler manual shows how to top it up.
Check your gas supply
Turn on a gas hob or another gas appliance. If nothing else is getting gas either, the supply is the problem — contact your gas provider. No gas to the property can bring up the F0 238.
Call a Gas Safe engineer
If pressure and gas supply are fine, the fault is most likely inside the boiler — the gas valve or control box. That’s where you stop and call a professional.
Don’t try to open up or fix the gas valve yourself. It isn’t safe, and it’s illegal to work on gas without Gas Safe registration.
If the checks come back clear, the fault is inside the boiler, and our boiler repair in London team can take it from there.
Get professional help
We’re a London team of Gas Safe engineers, and we work on every make and model — Worcester Bosch included. We’re accredited Worcester Bosch installers, so our engineers are trained to the manufacturer’s standards.
If your boiler is locked out on F0 238, we can diagnose the gas valve or control box and get your heating back on.
Call the helpdesk or book a heating engineer online.
Boiler stuck on F0 238? Call our London helpdesk or book a Gas Safe engineer online, and we’ll get your heat and hot water back.
