What is the flashing red light on my boiler?
Speak to an expertYour Worcester 28Si Mk1 boiler is an essential part of your home’s heating system. When it shows a flashing red light, it can be worrying, but understanding the possible causes and what you can do about them can help you solve the problem quickly and safely. In this article, we’ll explore some common reasons why your boiler’s red light might be flashing, how to troubleshoot the issue, and offer some boiler maintenance tips to help prevent future problems.

Possible problems
The flashing red light on your boiler is often an indication that there is a problem with the fan unit or the air pressure switch. Alternatively, it could be a sign that no power is getting to the fan. Various factors, including faults in the electrical supply or a build-up of debris within the fan itself, can cause these issues.
How do you stop the red light from flashing?
If you notice that your boiler’s red light is flashing, the first thing you should do is call a Gas Safe registered boiler technician. Attempting to fix the problem yourself could be dangerous and may invalidate your boiler’s warranty.
Turn your boiler off, and call an engineer who will begin doing some tests, which we will cover next.
Testing the fan
When the engineer arrives, they will need to remove the boiler’s casing to access the fan and air pressure switch. This involves removing a screw at the top of the case and then lifting off the casing. Next, they will remove the combustion cover, held in place by four screws. An engineer must also carry out this step.
Once the combustion cover is removed, the engineer will be able to test the fan unit. First, they will use a multimeter to check for voltage running through the fan’s leads. If the multimeter shows that electricity is running through the fan, this is a sign that the problem lies with the fan itself.
Replacing the Fan
If the engineer finds the fan faulty, they must replace it. Finding replacement parts for this boiler model can be tricky, as only some parts are available due to the boiler’s age. However, a Gas Safe registered engineer may be able to source the necessary parts and carry out the repair for you.
Troubleshooting tips
When you notice a flashing red light on your boiler, it’s important to call in a Gas Safe registered engineer to carry out any repairs. While there are a few basic troubleshooting steps you can take to help identify the issue, it’s important to note that you should refrain from attempting to fix the problem yourself. Checking the power supply and the pressure gauge are two common troubleshooting steps you can take to identify potential issues.
If you notice a problem with the power supply, check that the power supply to your boiler is turned on and that there is no issue with the fuse or circuit breaker. If the pressure gauge is reading too high or too low, it could also cause an issue. Again, however, it’s always best to call in a Gas Safe registered engineer to handle any repairs or maintenance to ensure the safety of yourself and your home.
Essential boiler maintenance
The number one way to prevent unexpected boiler breakdowns is through prevention. An annual boiler service will help ensure your boiler’s longevity and efficiency while saving you money on repairs and energy bills. That’s why we recommend a yearly boiler service with an experienced and proven boiler engineer to help prevent problems before they arise.
If you notice that your Worcester 28si mk1 boiler has a flashing red light, it’s important to call a Gas Safe registered engineer as soon as possible. They will be able to identify the cause of the problem and carry out any necessary repairs to get your boiler working safely and efficiently again. In addition, regular maintenance and basic troubleshooting steps can help you avoid future problems and keep your boiler in good working order. Remember, it’s always better to be safe than sorry when it comes to the safety of your home and family.
About the author
Trades Team are experts in Heating, Plumbing and Gas Services. We have 15 years of experience providing expert Boiler Repair and Boiler Servicing to homes and businesses across the Southeast. Learn more about Trades Team.
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