Glow-Worm Boiler F.88 Fault Code
The Glow-Worm fault code F.88 relates a problem with the boiler’s flame and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F.88 Error Common Q & A
Just below, we have a list of common questions relating to the F.88 fault code on the Glow-Worm Boiler.
- What does the F.88 fault code mean on my Glow-Worm boiler?
- Is there a DIY fix, to clear the F.88 fault code?
- What causes the F.88 fault code to be displayed on my boiler?
- Will I need to buy a new boiler if the F.88 fault code is being displayed?
- How does gas pressure affect the operation of my boiler?
- How would the flue or condensate pipe get blocked, and can they be fixed?
- Can an incorrectly adjusted gas valve be fixed?
- Can the burner be cleaned out to fix the F.88 fault code?
- How will my boiler engineer know if the gas valve is faulty?
- How much does a replacement gas valve cost?
- My boiler engineer thinks the PCB is the problem, does this sound correct?
What does the F.88 fault code mean on my Glow-Worm boiler
If your Glow-Worm boiler is showing the F.88 fault code on the display panel, it means there is a problem with the boiler’s flame.
This fault code relates to an unstable flame. So, whilst the boiler can create a flame, it may be fluctuating in strength or going out completely.
Is there a DIY fix, to clear the F.88 fault code
Gas appliances should on be worked on by Gas Safe accredited boiler repair specialists. If you aren’t Gas Safe, it’s not safe to try and fix the F.88 fault code.
There are some fault codes on boilers that are easy to fix and can be done so, without taking the boiler apart. An example would be topping up a boiler’s pressure.
Unfortunately, as this is an internal gas fault, so a DIY fix isn’t available.
What causes the F.88 fault code to be displayed on my boiler
Some boiler fault codes are incredibly specific. That means that the repair company will know exactly what the problem is, simply based on the code. Unfortunately, the F.88 fault code on Glow-Worm boilers, isn’t. There’s a whole host of things that could be causing the problem, including:
- Insufficient gas pressure
- Flue or condensate pipe blockage
- Incorrect gas valve adjustment
- Debris build-up in the burner
- Faulty gas valve
- Printed circuit board (PCB)
Your boiler repair engineer will have to go through a fault-finding process, to determine the problem.
Will I need to buy a new boiler if the F.88 fault code is being displayed
It’s unlikely that you’ll need a new boiler. However, depending on the exact fault, the cost of a repair could be upwards of £300.
Before your engineer fixes the problem, they should give you a cost estimate, and assess the state of your boiler overall. There’s little point investing large chunks of cash in a boiler that’s failing. So, ask them to check important components like the gas valve, PCB, fan, pump and air pressure switch, before making any big investments.
How does gas pressure affect the operation of my boiler
Your boiler won’t be able to feed to burner with the correct level of gas, if the pressure is too low. Older building regulations mean that some gas mains in the UK, may be short of current standards. So first, get your engineer to check that your gas main pipework can provide the burner with enough gas.
It might be that you’ve upgraded to a more powerful boiler, and the gas main is no longer able to keep up with the demand for gas.
Your boiler repair company will be able to pressure test to see what the pressure is coming into the meter, out of the meter, and to the boiler. This will help to isolate the problem.
How would the flue or condensate pipe get blocked, and can they be fixed
Your boiler’s airways need to be free of blockages to work correctly.
Starting with the flue, your engineer needs to check there’s no debris. Your flue will come out of your property horizontally (through the wall), or vertically (through the roof).
In the case of flue blockages, it’s most likely to occur with vertical flues. They should be fitted with a flue guard to stop debris dropping into the flue and blocking it. So, if you have a vertical flue and it’s not got a flue guard fitted, your engineer will need to fit one after clearing the blockage.
The condensate pipe takes condensed flue gases out of your boiler; it’s dangerous for them to stay in the appliance. If the condensate is blocked (for instance, the gases have frozen in wintry weather), the boiler is going to lock out.
Your boiler engineer will be able to clear the blockage by thawing out the condensate pipe. Once they’ve done this, they can lag the pipe, so this doesn’t happen again.
Can an incorrectly adjusted gas valve be fixed
Once gas travels through the mains and reaches the boiler, it’s down to the gas valve to control the flow of gas. It gets signals from the PCB, which tells the valve when it should open (for instance, when you turn on your heating) and when to close (when you turn off your heating).
If your gas valve is adjusted incorrectly, even when it’s told to open, it won’t be supplying the burner with enough gas.
Luckily, this is a faulty setup, not a faulty component. Your boiler repair company will be able to adjust the gas valve to work in harmony with your boiler. Once they’re happy it’s been adjusted correctly, they’ll then reset your boiler to clear the F.88 fault code.
Can the burner be cleaned out to fix the F.88 fault code
As the burner burns gas, it creates carbon build-up. This is minimal, but over time, it can be enough to block parts of the burner, so gas isn’t burnt efficiently.
Typically, we find that the carbon blocks up the jet supplying gas to the boiler. If this happens, gas won’t be flowing correctly. So, even if the ignition lead and spark generator are working correctly, they won’t be able to produce a flame. But, even if they’re able to, the fluctuation in gas supply to the burner will mean an unstable flame is produced.
Your boiler engineer will be able to remove the burner. If it’s in good condition, a replacement won’t be needed. Instead, they can clean the existing burner and jet, and then refit it.
How will my boiler engineer know if the gas valve is faulty
Now your boiler engineer has checked that the gas valve’s adjustment is correct, the next step is to determine whether the gas valve is faulty.
First, they’ll need to check that it operates freely. A large-scale problem with gas valves is that they stick. So, they might get stuck partially open, or partially closed, and won’t respond directly to the commands from the PCB.
If your gas valve is sticking, most of the time your boiler engineer will be able to free it.
However, if the problem runs deeper than this, your repair company will need to test the gas valve using a multi-meter. This will determine whether the gas valve has power.
If the gas valve doesn’t have power, or your boiler repair company can’t free the valve, a replacement will be needed.
How much does a replacement gas valve cost
A replacement gas valve for a Glow-Worm boiler is likely to cost in the region of £250-300; that includes parts and labour.
Expect the job to take 1 working day to complete. That said, parts will need to be ordered in, as it’s unlikely your engineer has a gas valve for your boiler, on their van.
What does the PCB do on my Glow-Worm boiler?
The PCB is the heart of your boiler. It gives and receives signals to all electrical parts, to make sure the boiler is working exactly how it should be.
That includes things like telling the gas valve when to open and when the pump should run
But, it also monitors a range of sensors. For instance, by getting signals from the air pressure switch, it knows when the fan is running, and therefore, that the boiler is safe to operate.
Essentially, without a fault-free PCB, your boiler is going to start to develop a whole host of problems.
My boiler engineer thinks the PCB is the problem, does this sound correct
The PCB can be connected to most fault codes, as this is the component that gives and receives signals to all electrical components in your boiler.
In fact, it’s the PCB that determines what fault code should be displayed in the first place. If it’s faulty, there’s a chance it could be:
- Displaying the wrong fault code
- Giving the wrong signals (for instance, not telling the gas valve to open when it should)
So, before replacing any parts, your boiler engineer will want to check that the PCB isn’t to blame. Because, if the PCB needs replacing, it could cost as much as £500.
Alongside another repair (such as a gas valve replacement, at around £300), it might make more sense to upgrade your boiler to a brand new efficient one, offering a long manufacturer’s warranty.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.