Why has your Worcester Bosch boiler started flashing with the blue light? Here we cover the most common causes and fixes.
You might be feeling pretty bewildered, if not alarmed to see a flashing blue on your Worcester Bosch boiler.
But fear not, because you’ve come to the right place to learn what this light means and what you can do to resolve it.
Let’s dive in and shine a ‘light’ on this issue.
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Quick Summary:
A flashing blue light on a Worcester Bosch boiler indicates a fault and is often accompanied with an error code.
Possible causes include gas supply issues, flue blockages, low pressure, or a blocked condensate pipe.
Troubleshooting steps involve checking the gas supply, topping up your boiler pressure and checking for blockages.
When to Call a Professional: If the problem persists after troubleshooting, contact a gas safe engineer for further inspection and repair.
In many cases, upgrading your old boiler to a new, more efficient model is the best solution.
Get a new quote (finance available including 0% APR).
Why Is There a Flashing Blue Light on My Worcester Boiler?
If you notice a flashing blue light on your Worcester boiler’s control panel, there are several potential explanations as to why this is happening.
In some cases, you might simply need to reset your boiler and in other cases, you’d need to hire a qualified heating engineer to fix a specific problem with your boiler.
When a flashing blue light is present on a Worcester boiler, an error code should also appear at the same time.
Each error code has its own meaning and as already alluded to, a variety of potential solutions.
Can I Fix This Fault Myself?
Before calling a professional, you can try a few simple DIY checks and fixes to potentially resolve the issue:
Inspect the flue for obstructions – Ensure there are no blockages that could be restricting airflow, as this can prevent the boiler from igniting properly.
Verify the gas supply – Check that your home’s gas supply is functioning correctly by testing other gas appliances. If they are working, the issue is likely boiler-specific.
Top up your boiler pressure - If caused by low boiler pressure, you can top it up yourself via the filling loop.
Reset the boiler – Follow the manufacturer’s instructions to perform a reset, which may temporarily resolve the fault and restore heating.
If the fault persists after these steps, professional assistance will likely be required.
Do I need to contact a gas-safe engineer to fix this issue?
If the issue isn’t resolved after following the basic DIY steps, then seeking the assistance of a Gas Safe registered engineer will be required. These qualified professionals are legally certified to work on gas boilers and will ensure that any repairs are carried out safely and in compliance with industry regulations.
Attempting to fix complex boiler issues without professional expertise can pose safety risks and may void your boiler warranty.
Common Causes Of The Blue Light Flashing
As mentioned, the Worcester Bosch blue light flashing is commonly caused by a gas supply issue, low boiler pressure and/or a block in the condensate or flue.
To determine which is the cause, the following error codes will typically be displayed accompanying the blue light:
Error Code EA - there is an issue with the gas supply or there is a flue blockage (depending on the model).
Error Code CE 207 - the boiler pressure is low.
Error Code D5 or EA - condensate pipe blockage.
Service Mode - when the blue light is flashing rapidly, this means your boiler has entered service mode.
Gas Supply Issue
For those with a Worcester Bosch Ri model, a blue flashing light and EA fault code together mean that gas is not being supplied to your boiler.
If this occurs and you suspect there is an issue with the gas supply, your first port of call should be to work out whether the problem is with your boiler or the gas supply itself.
For the latter, you can simply check other gas appliances throughout your home, if you have any (e.g., a gas hob or gas oven).
If none of your gas appliances is working, then you can be virtually certain that the issue is with the supply itself. If this is the case, you should contact your gas supplier.
On the other hand, if your boiler isn’t receiving a gas supply while other gas appliances are, you’ll need to hire a Gas Safe Register engineer.
They’ll be able to look at your boiler, identify the exact cause of the issue, and hopefully fix it there and then.
Read our Worcester Bosch vs Viessmann Boilers review if you need some help in choosing between these two popular brands.
Flue Blockage
A scenario where an EA fault code might appear with a Worcester boiler (and a flashing blue light) is if your boiler flue is blocked.
Image showing a standard flue
A blocked flue is a serious concern, as it prevents harmful exhaust gases from safely venting outside. This is why if obstructed, it will trigger your boiler to stop operation until the blockage is resolved.
If you suspect a flue blockage:
Turn off your boiler immediately to prevent further gas buildup.
Shut off the gas supply if you know how to do so safely.
Contact a qualified heating engineer as soon as possible to inspect and resolve the issue.
In some cases, the engineer may need to clear the blockage or replace the flue entirely. To prevent future obstructions, consider installing a flue guard, which helps keep out debris and potential blockages.
Low Boiler Pressure
As mentioned, a flashing blue light along with the Worcester CE 207 fault code relates to low pressure.
Image showing a standard pressure gauge
Low water pressure can trigger a flashing blue light on your Worcester boiler. To resolve this:
Check the pressure gauge – It should be between 1.0 and 2.0 bar (refer to your boiler manual for exact levels).
Increase pressure if too low – Open the filling loop valve slowly until it reaches the recommended range.
Avoid over-pressurising – If pressure gets too high, bleed the radiators to release excess water.
Still having issues? Contact a Gas Safe engineer for professional assistance.
Keeping your boiler pressure within the correct range helps maintain efficiency and prevent faults.
Blocked Condensate Pipe
When the fault code D5 occurs with a flashing blue light on a Worcester boiler, it typically means that your condensate pipe is blocked.
Image showing a standard condensate pipe
A flashing blue light on your Worcester boiler can sometimes appear alongside an EA fault code, indicating a blocked condensate pipe.
All condensing boilers have a condensate pipe designed to expel wastewater into an outside drain. However, during cold weather, this pipe can freeze, causing a blockage that prevents wastewater from draining properly.
The good news is that defrosting a frozen condensate pipe is often a simple DIY fix, provided you take the right precautions.
✅ How to Safely Thaw a Frozen Condensate Pipe:
Pour warm (not boiling) water over the pipe to melt the ice. Boiling water can damage the pipe.
Be cautious of splashes, as hot water can rebound off the pipe.
As the blockage clears, wastewater may flow out quickly, so stand back to avoid getting soaked.
If you’re unsure or the problem persists, contact a qualified heating engineer to safely resolve the issue.
Watch our video guide on how to unblock your condensate pipe here:
Related heating/energy guides:
Service Mode
If your boiler’s blue light is flashing in rapid succession, this means that your boiler has entered service mode.
This may be because it was unintentionally left in service mode by an engineer (during a recent servicing), or maybe you accidentally knocked off the switch yourself.
Will My Warranty Cover Repairs or Replacement Work?
Worcester Bosch warranties only cover repairs in the scenario that a defect is found that was the result of the manufacturing process.
In other words, if there is a problem with your boiler that resulted from its misuse or is unrelated to its manufacturer, the warranty will not apply.
Moreover, even if a defect may have resulted from its manufacture, you also need to ensure your boiler’s warranty is still valid.
You need to consider how long your boiler is in warranty and whether or not you have followed certain rules as set out in their Ts and Cs. As an example, a Worcester Bosch boiler must be serviced every year by a Gas Safe Registered engineer in order for its warranty to remain valid.
Cost of Fixing Your Boiler
There are many potential fixes that could apply to a flashing blue light and presumably an error code alongside it (more than we’ve covered here).
However, we’ll now look at the estimated price tag of the most common solutions.
Here are the costs of the potential solutions brought up today:
Unblocking a flue - £30 to £120
Replacing a boiler flue - £200 to £600
Repressurising a boiler - £30 to £120
Fixing a blocked condensate pipe - £30 to £120
Switching your boiler off service mode - £30 to £120
Replacing a boiler- £800 to £2,800
Do You Need A New Boiler?
In some cases, replacing a boiler can make more financial sense than continuing to repair it. Here are the key factors to consider:
Age of the Boiler - If your boiler has surpassed its average lifespan (typically beyond 15 years) and is no longer covered by the manufacturer’s warranty, replacing it may be a more cost-effective option to avoid recurring repair expenses.
Repair Costs - When the cost of repairing the boiler exceeds 50% of the price of a new one, it’s usually more financially sensible to invest in a replacement rather than continuing with costly repairs.
Frequency of Breakdowns - If your boiler is breaking down more frequently, it’s often a sign of significant wear and tear and it is beyond economical repair. In such cases, replacing the boiler can help avoid mounting repair costs and the inconvenience of ongoing issues.
Energy Efficiency - Older boilers tend to be far less efficient than modern models, leading to higher running costs. Upgrading from a G-rated to an A-rated boiler could save you up to £385 per year in energy bills, making replacement a financially smart decision in the long run.
By carefully weighing these factors, you can determine whether replacing your boiler offers better value and peace of mind compared to continued repairs.
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