Glow-Worm Boiler F.27 Fault Code
The Glow-Worm fault code F.27 relates to the fault means the safety switch is off and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F.27 Error Common Q & A
Just below, we have a list of common questions relating to the F.27 fault code on the Glow-Worm Boiler.
- What does the F.27 fault code mean on my Glow-Worm boiler?
- If the F.27 fault code is being displayed, what are the potential culprits?
- How would the electronics on my boiler become damaged?
- My boiler is noisier than usual, could this have contributed to the F.27 fault code being displayed?
- Why would the pump be making more noise than usual?
- How much will it cost to replace a pump on a Glow-Worm boiler?
- Is there a way to stop heating sludge from blocking up the pump again?
- How can the fan contribute to electronic failures?
- If I need to replace the boiler’s fan, how much is it going to cost?
- How can the flame sensor cause the F.27 fault code to be displayed on my Glow-Worm boiler?
- What does the gas valve have to do with the F.27 fault on my Glow-Worm boiler?
- Can the gas valve on my Glow-Worm boiler be fixed, to clear the F.27 fault code?
- What PCB faults can occur on Glow-Worm boilers?
What does the F.27 fault code mean on my Glow-Worm boiler
When your Glow-Worm boiler develops a problem, it will display a fault code on the display panel. This helps your boiler repair company to diagnose the problem quickly. It makes diagnosing the repair quicker than having to do so with no information, and therefore, reduces the repair cost.
When a fault code is displayed, it’s likely your boiler will lock out. This lock out isolates the boiler, as it might be dangerous. But, as with most faults, it also stops the boiler working, as continued operation could lead to further faults with internal components, and that’s going to lead to higher repair bills.
If the F.27 fault code is being displayed, what are the potential culprits
According to Glow-Worm, the F.27 fault means the safety switch is off. And, that’s due to a fault when the PCB tries to detect a flame in the burner.
The printed circuit board (PCB) is demanding gas and asking the boiler to ignite. But, the boiler isn’t igniting, or there’s a flame failure during operation.
The most likely culprits that your Gas Safe boiler engineer needs to check are the:
- Electronics, it’s likely they’re damaged, or have worked their way loose
- Flame sensor, as this component could be faulty
- Gas valve, this could be sticking closed
Although that’s not a full list of the potential faults, these are the problems that are most likely to be causing the F.27 fault code to be displayed on your Glow-Worm boiler.
How would the electronics on my boiler become damaged
All boiler components wear with old age. Electronic components are susceptible to damage, simply because they’re extremely fragile.
Older boilers tend to be incredibly inefficient. And, much of this inefficiency comes from internal boiler vibrations. But, it’s these boiler vibrations that can also lead to components getting damaged, as well as wires and connections coming loose.
In many cases, the simple fix, is having a Gas Safe boiler repair engineer to re-secure wires and connections. If even one is loose, your boiler won’t work correctly.
My boiler is noisier than usual, could this have contributed to the F.27 fault code being displayed
If your boiler has been making more noise than usual, the root cause of the problem needs to be found. Typically, we find that there’s a fault with the boiler’s pump, or the fan. When problems develop, they vibrate more than usual, and that’s what is causing the boiler to make more noise than usual.
Why would the pump be making more noise than usual
The first thing to check, is that heating sludge hasn’t found it’s way into the pump. Heating sludge is a build-up of rust and can start to block the pump. That’s going to mean that the component is putting itself under excess pressure, to be able to circulate water in the way it should. And, that’s going to lead to parts in the pump wearing out quicker than they should.
If sludge is an issue, it’s likely the pump’s bearings are worn, and the shaft isn’t turning correctly. Some pump manufacturers offer a service kit which can be used to recondition the pump. However, if the pump is excessively worn, it makes sense to replace the whole unit.
How much will it cost to replace a pump on a Glow-Worm boiler
Most heating engineers prefer to use Grundfos pumps, as they’re a reputable brand. You should expect the cost of installing a new pump, including parts and labour, to be in the region of £250.
Is there a way to stop heating sludge from blocking up the pump again
There are preventative measures that can be put into place to stop this happening again.
First, ask your boiler repair engineer to run a hot flush. They’ll use chemicals and heat, to flush out heating sludge that’s currently in your system.
Next, they’ll want to top up the boiler’s pressure, making sure the correct level of central heating inhibitor is dosed in the system. This breaks down any future rust that comes from the inside of copper pipework and radiators.
Finally, they’ll need to add a magnetic boiler filter. This catches all the sludge that the central heating inhibitor has broken down, so this debris doesn’t pass through the boiler, and cause damage.
How can the fan contribute to electronic failures
Like the pump, if the fan’s bearings are worn, it won’t be turning on the shaft smoothly. If possible, your boiler repair engineer will be able to replace the fan’s bearings. But, if the fan is excessively worn, it’s likely that they’ll suggest a replacement instead.
If I need to replace the boiler’s fan, how much is it going to cost
The fan replacement on your Glow-Worm boiler, will be similar in price to the pump. Expect to pay £250 including parts and labour.
How can the flame sensor cause the F.27 fault code to be displayed on my Glow-Worm boiler
When your boiler goes to fire up, all electronic components are controlled by the PCB. This first, tells the fan to fire up; it’s the fan that helps harmful flue gases escape via the flue. Then, the air pressure switch acts like a sensor, telling the PCB that the fan is running.
The boiler is then safe to ignite. Once it’s ignited, the PCB needs to see a signal from the flame sensor, to check there’s a flame. This sensor constantly monitors the flame on the boiler, as sometimes issues can lead to a flame being present, when it shouldn’t be.
In this case, it’s more likely no flame is present, when it should be. A potential culprit here, is the flame sensor. If your boiler engineer can see a flame, but it’s not being detected by the flame sensor, that’s the issue.
To double check, they can test the flame sensor using a multi-meter. This allows them to test the flame sensor for power. If it doesn’t have power, and the wires and connections are in good condition and all connected, it’s the flame sensor that’s at fault; a replacement sensor will be needed.
What does the gas valve have to do with the F.27 fault on my Glow-Worm boiler
If the gas valve isn’t opening, it’s not providing gas to the burner, and there’s going to be no ignition, and no flame.
Your boiler engineer will want to check that the valve isn’t sticking. These valves are mechanical parts, so can stick in any position (open, closed, partially open and partially closed).
In this case, it’s likely that the gas valve is stuck closed. That’s going to mean that the burner is either:
- Not getting enough gas to ignite
- Getting no supply of gas at all
Can the gas valve on my Glow-Worm boiler be fixed, to clear the F.27 fault code
On most occasions, the gas valve can be fixed. Your boiler engineer needs to check the valve using a multi-meter, to check it’s getting power. Intermittent power is a sign of weak connections, wiring, or a possible PCB fault.
If the power to the gas valve is fine, the valve needs to be freed, so it operates smoothly.
On some occasions, the gas valve can’t be repaired, or it’s excessively worn, and a replacement makes more sense than a repair. If this is the case, you should expect to pay somewhere in the region of £300 for a replacement.
What PCB faults can occur on Glow-Worm boilers
The PCB is one of the most important parts of your boiler. If the PCB doesn’t work, neither will any of the other electrical components.
One thing worth considering, is that it’s the PCB that controls the fault codes that are displayed on your boiler. If the PCB isn’t working correctly, there’s a good chance that the fault code being displayed isn’t correct either.
So, if you’re boiler engineer has checked the gas valve, flame sensor, pump, fan, wires, connections and still can’t find the problem, they need to start looking at the PCB.
Like other electronic components on your boiler, they’ll be able to test this using a multi-meter. Unfortunately, if the PCB needs replacing, it’s not a cheap component to replace. Expect a PCB replacement to be in the region of £500.
Due to the expense of a PCB, and the fact that other components may also need replacing, it’s sometimes worth getting quotes for a new boiler, rather than paying for repairs.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.