Glow-Worm Boiler F70 Fault Code
The Glow-Worm fault code F70 relates to the printed circuit board (PCB) not being setup correctly and here we have Q & A or require an engineer for an emergency boiler repair.
The Glow-Worm Boiler Fault Code F70 Error Common Q & A
Just below, we have a list of common questions relating to the F1 fault code on the Glow-Worm Boiler.
- What does the F70 fault code mean on my Glow-Worm boiler?
- What does the PCB do on my Glow-Worm boiler?
- If the F70 fault code is being shown on the display panel, how can my engineer determine what the fault is?
- Can the F70 fault be fixed on a DIY basis?
- How will my boiler repair company know if the PCB has been set up incorrectly?
- What is a user interface fault?
- What is a boiler chip card, and how can that cause the F70 fault code to be displayed?
- How will my boiler engineer know if the problem is with the main PCB?
- What could have caused the PCB failure on my Glow-Worm boiler?
- I need a new PCB; how much is this going to cost?
What does the F70 fault code mean on my Glow-Worm boiler
If you’re having problems with your Glow-Worm boiler, you’ll see a fault code displayed on the user interface. In most cases, this is also going to lead to the boiler locking out.
When a boiler lock out occurs, in some cases, this is to protect internal components. However, in the case of the F70 fault code on Glow-Worm boilers, it’s happened because the printed circuit board (PCB) isn’t setup correctly; there is a software compatibility fault.
What does the PCB do on my Glow-Worm boiler
The PCB is the most important component in your boiler. It’s the PCB that gives and receives signals from all other components.
By doing so, it can determine which parts need to be operating and when. It also gives and receives signals from a range of sensors to determine if there are problems, such as your boiler overheating, and even if flue gases aren’t being expelled from the boiler.
As an example, the PCB wants to see a rise in temperature once the boiler fires up. It receives a signal from the NTC thermistor on the flow pipe. If there isn’t a rise in temperature, this signifies there’s a problem.
And on some occasions, the PCB can recognise where the fault lies. For instance, this could be a lack of gas supply to the burner, a blocked burner, or even a pump that’s not circulating water correctly.
By monitoring all the electronic components in your boiler, the PCB helps to keep it operational, but safe at the same time.
If the F70 fault code is being shown on the display panel, how can my engineer determine what the fault is
With software incompatibility faults, it’s most likely that the fault lies with something connected to the PCB. Typical examples of problems that lead to the F70 fault code being displayed include:
- Incorrectly set up PCB
- User interface fault
- Boiler chip card fault
- Problems with the main PCB
Can the F70 fault be fixed on a DIY basis
The F70 fault code can’t be fixed on a DIY basis. Your boiler will need to be taken apart, which is classed as working on a gas appliance. The only people allowed to work on gas appliances are Gas Safe engineers.
An emergency Gas Safe company will be able to take apart your boiler, fault-find to find the problem, fix it, and then reset your boiler to clear the fault code.
If you try to reset the boiler on a DIY basis, it’s unlikely to achieve anything. The reset function on your Glow-Worm boiler is designed to clear a fault code when the problem is fixed, not to fix the problem.
How will my boiler repair company know if the PCB has been set up incorrectly
The first thing your boiler repair company will need to check, is that the software has been installed correctly on your PCB. If you’ve had a new PCB, or a new boiler, there’s a chance that the PCB hasn’t been configured correctly by your engineer.
Modern boilers and their PCBs are extremely easy to setup. After installation, your boiler engineer will need to input a product code. This is a unique code to the PCB that allows it to work in harmony with the boiler. If this hasn’t been done by your boiler engineer previously, the PCB won’t work, and neither will the boiler.
What is a user interface fault
The user interface is the display panel on the front of your boiler. It might include things such as a timer, dials to turn temperature up and down, as well as dials to turn heating and hot water on and off.
This is directly connected to the PCB. Whilst the F70 fault code can mean there’s a fault with the main PCB, it might just seem that’s the case, due to the problem being with the user interface.
A simple case of loose or damaged connections is enough to cause a user interface fault. The lack of an electrical circuit, or an intermittent circuit, is going to mean that you can’t operate your boiler as usual, via the user interface.
When this happens, you might find that you come across a range of problems that happen on an intermittent basis including:
- The dials on the front of the boiler don’t work
- The LEDs and display come on and off at random
- Your boiler works intermittently and doesn’t always respond to input commands on the user interface.
By removing the user interface, your boiler engineer will be able to check over the electronics, to check their condition. Securing loose wires or repairing damaged connections should be enough to fix the problem. With a reset, your engineer will then be able to clear the fault code from the user interface.
What is a boiler chip card, and how can that cause the F70 fault code to be displayed
Boiler manufacturers sell a range of different models. For each one, they don’t produce model specific PCBs. Instead, they use generic PCBs. This helps to keep development costs of a new boiler to a minimum, and that means sale prices can be kept as low as possible too.
For a range of boilers to work with generic PCBs, they need to install a boiler chip card. Essentially, this is a device that provides compatibility. Boiler chip cards help your Glow-Worm boiler recognise and work in harmony with your boiler’s PCB.
If your boiler chip card is incorrect, damaged or has worked loose, there’s going to be a PCB or user interface fault, as it’s not longer going to recognise the PCB.
Your boiler engineer, after assessing the state of the user interface, will need to ensure that the boiler chip card isn’t to blame.
How will my boiler engineer know if the problem is with the main PCB
After checking your user interface, the PCB’s installation and the boiler chip card, the next step is to ensure that the PCB unit isn’t at fault.
As we’ve already mentioned, the PCB is the most important part of your boiler. Even the smallest of faults could lead to your boiler working sporadically, or not at all. If you have a problem with the PCB, you might have noticed things like:
- Heating and hot water comes on at random
- Appliance cycles on and off before getting up to temperature
- User interface doesn’t respond
- User interface is showing no sign of life
As you can see, once your PCB develops problems, it’s unlikely your boiler is going to work.
Your boiler engineer will need to test the PCB on your Glow-Worm boiler using a multi-meter. This will help to determine if and where there is power; that includes the PCB, and all its wires and connections.
If the issue lies with wiring and connections, these can usually be repaired. However, if the root cause is a PCB failure, it’s going to need to be replaced to clear the F70 fault code.
What could have caused the PCB failure on my Glow-Worm boiler
The most obvious cause of a PCB failure would be old age. PCBs are fragile electrical components. If the PCB has failed after years of use, it’s likely other parts in the boiler are likely to follow suit.
However, the fault could be excessive boiler vibrations. These can occur when parts like the pump or fan have bearings that are old and worn. They no longer operate smoothly, and instead, cause lots of boiler vibrations.
This can easily cause damage to fragile electrical components such as the PCB. So, if you’ve noticed that your boiler has been noisier than usual, this could be the reason why.
Another potential fault is a small boiler leak. So, it’s worth asking your boiler engineer if they’ve found any evidence of moisture in your boiler. As old electrical units aren’t as tightly sealed as new ones, any kind of moisture build-up could destroy your PCB. Typically, these leaks can come from the heat exchanger or pump.
If your boiler engineer suspects excessive boiler vibrations or leaks as the root cause, these need to be fixed alongside your PCB fault.
I need a new PCB; how much is this going to cost
If your boiler repair company has determined that it’s the PCB that’s causing issues, you’ll need a replacement.
Typically, this is the most expensive part on a boiler to replace. Expect to pay somewhere in the region of £400-500, and the job to take around one working day.
As with all repairs that are this expensive, it’s wise to have your boiler engineer assess the condition of your Glow-Worm boiler.
There are lots of expensive parts in your appliance, including the gas valve, fan, pump and heat exchanger. If multiple parts are showing signs that they’ll fail soon, it’s likely a replacement is going to be a more cost-effective option for you long term, over a repair.
Other Glow Worm boiler issues
For more boiler issues regarding the Glow Worm then please visit the Glow Worm Boiler Problems And Cures page.