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Machines can encounter problems at some stage and use codes to indicate the error in operation. Boilers also run into these problems due to mechanical faults or low pressure.
One of those faults is the f28 error code, which indicates a gas valve or ignition problem. Brands like Vaillant Boiler and Glow-Worm Boiler are reliable gas boilers but can still face these problems.
This article discusses the causes and quick fixes of the f28 fault code in Vaillant and Glow-worm boiler systems. Bear with us as we learn to fix the f28 code.
UPSHORTS:
- F28 fault code on the Vaillant & Glow-Worm boiler means your gas boiler has ignition or gas valve-related issues.
- Common causes of the F28 fault code are: No gas, gas valve broken, Ignition parts broken, condensation Pipe freezes, and Faulty wiring.
- Try DIY methods if you can spot a repairable cause.
- Hire Gas Safe engineers if the problem persists.
What Is the F28 Boiler Fault Code?
F28 fault code occurs in the valiant or worm boilers and is usually caused by low boiler pressure, mechanical issues with the gas valve, or frozen condensate pipe blockage. This fault is primarily related to the ignition of the boiler. It appears when the gas boiler fails three ignition attempts.
The combi boilers apply the safety lock to prevent the buildup of unburned gases. You can check if your gas valve is working fine or look out for other ignition components.
What Are the Causes of the F28 Gas Boiler Fault Code?
On a freezing winter morning, when your boiler shows error codes instead of providing hot-water, you might think “What the heck is wrong with this appliance?” Well, we will be disclosing the potential causes below, so let’s have a look together.
- Natural Gas Supply Issue: due to scheduled maintenance of gas service, your boiler will face ignition problems. This might also be caused by issues with the gas meter.
- Gas Valve Fault: a defective gas valve can cause obstruction in gas flow, leading to the boiler’s ignition failure and a display of f28 error code.
- Ignition Components Breakage: components like electrodes, burners or PCB can cause ignition faults.
- Frozen Condensation pipe Blockage: the blockage of condensing pipe which leads to low boiler pressure and triggers the f28 error code.
- Electric Faults in Control Panel: as we know boiler components are connected electronically, and errors in the control panel can disrupt the communication within the components and cause these error codes.
- Lower Boiler Pressure: problems like water leaks or damaged pressure relief-valve can stop your heating systems from igniting.
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How To Fix the Worm & Vaillant F28 Error Code?
If your gas boiler displays the f28 error code, it might be due to some obvious reasons like no gas supply or lower water pressure. Sometimes, troubleshooting these errors can be as simple as pressing the boiler reset button.
If you can spot the cause, you might be able to solve this problem through DIY methods. However, you might need gas-safe engineers to check your boiler system.
Here are the troubleshooting steps you can take as DIY to solve the f28 fault code:
1. Check the Gas Supply
It is ideal to check if your boiler is getting the operational gas supply for igniting the burner. You can check other gas appliances to confirm the cause. You should also check the electric sockets if those are providing the spark needed to heat your boiler.
When you are sure the lack of gas is causing the f28 error code, you can check the gas valve or contact the energy supplier if there is any maintenance going on.
2. Inspect the Boiler Pressure Gauge
Lower or high pressure of the boiler also causes the Vaillant boiler f28. So, you should check if your pressure gauge is showing a pressure between 1 to 2 bars.
If it’s lower than 1, that means it’s too low and you need to repressurise your heating system. However, if it’s above 2 bars, you need to release the load through the relief valve and bleed the radiators.
3. Look for Damages to Ignition Components
Watch out if you can find any visible damage to the electrodes or ignition leads. If you find any faulty components, replacing them should solve the error if that was due to a mechanical fault.
4. Clean the Flame detection Components
components like the thermocouple or the flame sensor can be the underlying issue causing the f28. You can clean the rust and dust to see if that works. Often, dirty flame-sensing components can be the issue causing the boiler to shut.
5. Pour Warm Water on the Frozen Condensate Pipe
If the fault code on your Vaillant boiler or Glow-Worm boiler persists, you should check if your condensation pipe is frozen. It usually gets frozen in absolutely cold months.
You can pour warm water outside the condensate pipe and see if this regulates the boiler pressure. However, make sure you are not pouring boiling water on the pipe, rest it for 10 minutes before pouring it on the pipe.
6. Seek Professional Help From a Gas Safe Engineer
If nothing from the above troubleshooting works, you should immediately contact a gas-safe registered engineer. HVAC companies like ECO Energy Services have the most experienced and accredited engineers. So, if you want your boiler to be up and running in no time, seek professional assistance.
However, before contacting the services, you should make sure you have checked for all the potential causes and see any basic issue causing the f28 error.
How Do I Fix the F28 Error Code on a Vaillant Boiler?
You need to get the root cause of the error in order to solve it. If the problems are caused by low boiler pressure or no gas supply, you can solve them through DIY.
However, if you are unable to identify the causes of the f28 fault, you should reach out to gas-safe registered engineers.
What Are the Common Causes of the F28 Fault on a Boiler?
The most common causes may include:
- No Natural Gas Supply
- Faulty Gas Valve
- Damaged Ignition Components
- Blocked Condensation Pipe
- Faulty wiring or Damaged Control Panel
- Lower Boiler Pressure
Does Cold Weather Cause F28 Error Code in Glow-Worm Boiler?
Yes, cold weather can freeze the condensation pipe, which can lead to the f28 fault code. You should insulate the condensing pipes to avoid your boiler leading to the f28 error.
If the pipes are already frozen, you can gently pour the warm or hot water on the pipes or thaw them with a hot water bottle to unfreeze the water and regulate boiler pressure.
Final Thoughts
The boiler f28 fault can be a real stressor in cold weather, cutting the access to hot water and heating for the central-heating.
Usually, resetting your boiler can do the job (no you don’t need boiler replacement if no serious problems occur) or your boiler is an older model. The Vaillant boiler f28 error code needs immediate attention and quick fix methods might work if you understand the problem.
In this article, we have discussed how you can fix your Vaillant boiler or Glow-Worm boiler. If you are also facing an f28 error on a Vaillant or glow-worm boiler, you should contact Gas Safe register engineers if troubleshooting does not work.
FAQs
The F28 error code on a Glow-Worm or Vaillant boiler indicates an ignition fault. This means that the boiler is failing to ignite and, as a safety measure, has locked itself out. This issue can arise due to several reasons, including:
- Gas supply issues – No gas reaching the boiler due to a supply cut, a closed gas valve, or low pressure.
- Frozen condensate pipe – In cold weather, the condensate pipe may freeze, blocking proper function.
- Faulty ignition leads or electrodes – Worn-out ignition components prevent proper sparking.
- Gas valve problems – The gas valve may be stuck, faulty, or misaligned.
- Flue or fan problems – A blocked flue or malfunctioning fan can impact ignition.
If you notice the F28 fault code, it’s important to diagnose the issue carefully before attempting any fixes.
Whether you can fix the F28 error code yourself depends on the cause of the issue. Some minor problems can be resolved without professional help, while others require a Gas Safe engineer.
You Can Fix It Yourself If:
- Gas supply was turned off – Ensure the gas valve is fully open.
- Condensate pipe is frozen – Carefully thaw the pipe using warm water or a hot cloth.
- Resetting the boiler works – Sometimes, a simple reset clears the fault.
You Need a Professional If:
- There is an issue with the gas valve, ignition electrodes, or PCB (Printed Circuit Board).
- You suspect a gas leak or notice a smell of gas.
- Resetting the boiler doesn’t resolve the issue.
Since working with gas appliances is dangerous and regulated, do not attempt to repair gas-related components yourself.
Yes, resetting your Vaillant boiler may resolve the F28 fault if it’s a temporary issue. To reset:
- Locate the reset button – On most Vaillant models, it’s marked with a flame symbol and a line through it.
- Press and hold the button for 3–5 seconds – The boiler should attempt to restart.
- Wait for the boiler to fire up – If the fault clears, the boiler should work normally.
If the F28 error persists after resetting, it suggests an underlying issue that requires further inspection.
If you’ve checked your gas supply, reset the boiler, and thawed the condensate pipe but the error persists, then yes, you should contact a gas-safe engineer.
A professional can:
- Inspect and test the gas valve for faults.
- Check and clean the ignition electrodes.
- Assess the PCB and replace any faulty components.
- Verify flue and fan operation to ensure proper air circulation.
Since working with gas appliances requires certification, it is always safer to have a qualified engineer handle complex issues.
