Glow-Worm Boiler F.28 Fault Code
The Glow-Worm fault code F.28 relates to a unsuccessful ignition attempt and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F.28 Error Common Q & A
Just below, we have a list of common questions relating to the F.28 fault code on the Glow-Worm Bosch Boiler.
- What does the F.28 fault code mean on my Glow-Worm boiler?
- What causes the ignition failure on my Glow-Worm boiler?
- What can affect the gas pressure on my Glow-Worm boiler?
- What does the flue have to do with the F.28 fault code being displayed?
- If the gas valve on my boiler has been incorrectly adjusted, can it be fixed?
- Why would the ignition lead/electrode suddenly become faulty?
- How will my boiler repair engineer know if the gas valve is faulty?
- My boiler engineer thinks the gas valve needs replacing, how much will this cost?
- How does debris find its way into the burner, and can it be fixed?
- What is the spark generator on my boiler, and can it be fixed?
- What else could be causing the fault on my Glow-Worm boiler?
- My PCB is broken, how much does it cost to fix?
What does the F.28 fault code mean on my Glow-Worm boiler
When your boiler develops a fault, the printed circuit board (PCB) displays a fault code on the control panel. This gives your Gas Safe engineer an indication of the fault, rather than them having to diagnose the fault from scratch.
The F.28 fault code on Glow-Worm boilers relates to an unsuccessful ignition attempt.
What causes the ignition failure on my Glow-Worm boiler
Unfortunately, the F.28 fault code isn’t specific. There is a fault-finding process that your boiler engineer is going to need to go through, to fix your boiler.
The issue could lie with the:
- Gas pressure
- Flue airway being blocked
- Gas valve being adjusted incorrectly
- Electrode and/or ignition leads being faulty
- Gas valve being faulty
- Burner having debris in it
- Spark generator being faulty
As you can see, that’s a lot of things to check and test. The F.28 fault code could relate to one or more of the issues above being present.
What can affect the gas pressure on my Glow-Worm boiler
First, is this a new boiler install? If it is, it might be that the gas mains can’t cope with the extra demand from a new and more powerful boiler. If this is the case, the gas main will need to be upgraded by your boiler installer.
If this isn’t a new install, it’s more likely there’s an air pocket in the gas main, and this is going to act as a blockage.
Alternatively, if it’s cold currently, there’s a chance that the gas meter’s regulator has frozen. If this is the case, you’ll need to get your boiler repair engineer to box in the gas meter, so it’s protected from the elements.
What does the flue have to do with the F.28 fault code being displayed
If there’s an airway blocked, it’s not safe for the boiler to operate. The two main airways to consider, are the flue, and condensate pipe.
Modern condensing boilers push condensed flue gases out via the condensate pipe. In cold months, these are prone to freezing. This creates a blockage, and the boiler will lock out. Your boiler engineer will be able to thaw out the pipe, and then cover it in lagging. This will protect the pipe during colder weather.
Likewise, your Gas Safe engineer will need to check the flue. In some cases, flues can break apart, essentially, blocking themselves. If this isn’t the case, it’s more likely a vertical flue has been fitted without a flue guard, and debris is causing the blockage.
If the flue is breaking apart, it needs to be replaced. However, if it has debris in it, it can be stripped and cleaned. Once it’s refitted, your boiler repair engineer can install a flue guard to stop this happening again in the future.
If the gas valve on my boiler has been incorrectly adjusted, can it be fixed
Gas valves can be adjusted, allowing the correct amount of gas into the burner. Your boiler engineer will want to first, test the gas valve to check that there are no faults. If the valve is in good condition, they’ll be able to adjust the valve.
Once adjusted, your boiler repair company will then reset the boiler. This will clear the fault code from the display panel.
Why would the ignition lead/electrode suddenly become faulty
There are several things that can lead to electrical failures in a boiler, including:
- Old age
- Moisture
- Boiler vibrations
It may be that the boiler’s ignition lead, and electrode need to be replaced, due to old age.
But, if a problem such as moisture or internal vibrations has caused the issue, the root cause of the problem needs to be found, before changing the ignition lead and electrode.
For example, moisture could be coming from an internal boiler leak (such as a faulty pump). Not only does this mean that a new ignition lead, or electrode are likely to suffer from moisture damage again, there’s a good chance the moisture is damaging other internal components.
Likewise, with boiler vibrations. If your boiler has suddenly become noisy, then stopped working, it’s likely that it’s developed a fault with the pump, or fan. If they are straining during operation, they’ll vibrate more than usual, and cause damage to fragile components.
So, it’s not just important to figure out which electrical component needs fixing, but also, to check what caused the problem in the first place. This is going to help you avoid expensive boiler repair bills in the future.
How will my boiler repair engineer know if the gas valve is faulty
Your boiler repair company can check the gas valve for power, as well as checking that it operates smoothly. If a fault is present, the supply of gas to the burner is going to be intermittent, or non-existent. And, that’s going to be enough for the boiler to suffer from ignition failures, time and time again.
My boiler engineer thinks the gas valve needs replacing, how much will this cost
If the gas valve isn’t getting power, is excessively worn, or keeps getting stuck, you’ll need a replacement.
Typically, a gas valve replacement including parts and labour, will cost in the region of £250-300. This will vary, depending on the model of boiler that you own.
How does debris find its way into the burner, and can it be fixed
Another possibility here, is that the burner is blocked. So, even though the gas valve is trying to give a steady supply of gas to the burner, it’s not able to, due to the blockage.
This should become immediately obvious to your boiler engineer, upon inspection of the burner. It’s most likely that the burner is blocked with carbon. The jet on the burner that provides the gas is incredibly small. So, even the smallest piece of debris can cause a serious enough of a blockage, to halt the flow of gas.
Your emergency boiler repair company will need to clean the burner, and the jet. After re-installing these components, they’ll be able to reset the boiler and clear the F.28 fault code from the control panel.
What is the spark generator on my boiler, and can it be fixed
The spark generator does exactly what it says on the tin; creates a spark. It creates a spark, so that when the gas valve provides gas to the burner, it can light the gas and produce a flame.
So, if the spark generator isn’t working correctly, a spark and flame won’t be produced; the boiler locks out after multiple attempts to ignite.
The spark generator is usually not a part that’s fixed. It’s much easier to fit a replacement.
What else could be causing the fault on my Glow-Worm boiler
If your boiler repair company has exhausted all the options mentioned above, they’ll need to test the PCB. The PCB controls all electrical components. So, whilst it might seem that one electrical component isn’t functioning correctly, it could simply be receiving the wrong signals from the PCB.
Your boiler engineer will be able to test the PCB, using a multi-meter. Sometimes, loose wiring and connections are all that’s needed to cause a fault. In other instances, it might be that moisture has completely ruined the component.
My PCB is broken, how much does it cost to fix
The PCB isn’t just the most important part in the boiler, it’s also the most expensive. If you need to replace your PCB, you should expect the cost to be in the region of £450-500.
Before replacing it, ensure your engineer checks all other expensive components. This includes the likes of the gas valve, pump and fan. If one or more of these parts also need replacing, it might be time to consider a new boiler.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.