A combi boiler is an essential appliance that provides hot water and central heating for your home. One of the critical components of a combi boiler is the flame sensor. The flame sensor is responsible for detecting whether the burner is lit or not. If the sensor detects that the burner is not lit, it will automatically shut off the boiler. However, like any other component, the flame sensor can encounter problems over time. In this article, we’ll discuss the most common issues that can arise with a combi boiler’s flame sensor, and how you can fix them.
Understanding the Combi Boiler’s Flame Sensor
A combi boiler’s flame sensor is a safety device that ensures the burner is lit before allowing the boiler to operate. The sensor detects whether there is a flame present in the combustion chamber. If it detects that there is no flame, it will shut off the gas supply to the burner, preventing a buildup of gas and potential explosion.
Symptoms of a Faulty Flame Sensor
If your combi boiler’s flame sensor is faulty, it can cause a range of issues that affect the boiler’s performance. Here are some common symptoms of a faulty flame sensor:
Burner Failure
If the flame sensor is faulty, the burner may not ignite, and the boiler won’t produce heat or hot water. This can be a significant issue, especially during the winter months.
Boiler Keeps Shutting Off
If the flame sensor is faulty, it may send a false signal to the boiler, causing it to shut off even when there is a flame present. This can cause the boiler to cycle on and off, resulting in inconsistent heating or hot water.
Yellow Flames
A faulty flame sensor can also cause the burner to produce yellow flames instead of blue. This can be dangerous as yellow flames can produce carbon monoxide, a toxic gas.
Causes of Flame Sensor Issues
Now that we’ve covered the symptoms of a faulty flame sensor, let’s discuss the causes of these issues.
Dirty Flame Sensor
One of the most common causes of flame sensor issues is a dirty flame sensor. Over time, the sensor can become covered in soot or debris, which can prevent it from detecting the flame correctly.
Corrosion
Another common cause of flame sensor issues is corrosion. Corrosion can occur when the flame sensor is exposed to moisture, which can cause rust to form on the sensor. This can interfere with the sensor’s ability to detect the flame correctly.
Wiring Issues
Wiring issues can also cause problems with the flame sensor. Damaged or corroded wiring can prevent the sensor from receiving the signal it needs to detect the flame.
How to Clean a Flame Sensor
If your flame sensor is dirty, you may be able to clean it yourself. Here’s how:
Step 1: Turn Off the Power
Before attempting to clean the flame sensor, you should turn off the power to the boiler to ensure your safety.
Step 2: Remove the Flame Sensor
The flame sensor is usually located near the burner. You’ll need to remove the sensor carefully, taking care not to damage the delicate components.
Step 3: Clean the Flame Sensor
Once you’ve removed the flame sensor, you can clean it using a soft brush or cloth. Be gentle and take care not to damage the sensor.
Step 4: Reinstall the Flame Sensor
Once you’ve cleaned the flame sensor, you can reinstall it in the boiler. Make sure to reattach any wires or connections carefully.
How to Fix Corrosion on the Flame Sensor
If your flame sensor is corroded, you may need to take additional steps to fix the issue. Here’s what you should do:
Step 1: Turn Off the Power
As with cleaning the flame sensor, you should turn off the power to the boiler before attempting to fix corrosion on the flame sensor.
Step 2: Remove the Flame Sensor
Carefully remove the flame sensor from the boiler, taking care not to damage any wires or connections.
Step 3: Clean the Flame Sensor
Clean the flame sensor using a soft brush or cloth. Once you’ve removed any corrosion, you’ll be able to see if there is any damage to the sensor.
Step 4: Apply Anti-Corrosion Solution
If there is no damage to the sensor, you can apply an anti-corrosion solution to help prevent future corrosion. Follow the manufacturer’s instructions carefully when applying the solution.
Step 5: Reinstall the Flame Sensor
Once you’ve applied the anti-corrosion solution, you can reinstall the flame sensor in the boiler.
How to Fix Wiring Issues
If your flame sensor issues are caused by damaged or corroded wiring, you may need to replace the wiring. Here’s how:
Step 1: Turn Off the Power
Before attempting to fix wiring issues, you should turn off the power to the boiler to ensure your safety.
Step 2: Inspect the Wiring
Inspect the wiring to see if there is any damage or corrosion. If you see any issues, you’ll need to replace the damaged wiring.
Step 3: Replace Damaged Wiring
If there is damaged wiring, you’ll need to replace it. Follow the manufacturer’s instructions carefully when replacing the wiring.
Step 4: Reinstall the Flame Sensor
Once you’ve replaced any damaged wiring, you can reinstall the flame sensor in the boiler.
Frequently Asked Questions
What is a combi boiler?
A combi boiler is a type of boiler that provides hot water and central heating on demand. It is a single unit that combines a water heater and a central heating boiler, making it a space-saving and energy-efficient solution.
What does a flame sensor do?
A flame sensor is a safety device that detects whether the burner is lit or not. If the sensor does not detect a flame, it will shut off the gas supply to the burner to prevent the buildup of gas and potential explosion.
How do I know if my flame sensor is faulty?
If your flame sensor is faulty, you may experience issues such as the burner failing to ignite, the boiler repeatedly shutting off, or yellow flames instead of blue. A professional technician can perform a diagnostic test to determine if the flame sensor is the issue.
Can I clean the flame sensor myself?
Yes, you can clean the flame sensor yourself, but it’s essential to follow the manufacturer’s instructions carefully and take care not to damage the delicate components.
Can I fix corrosion on the flame sensor myself?
If you’re confident in your DIY skills, you can attempt to fix corrosion on the flame sensor yourself. However, it’s essential to follow the manufacturer’s instructions carefully and take appropriate safety measures.
Should I attempt to fix wiring issues myself?
It’s always best to hire a professional technician to fix wiring issues to ensure that the job is done safely and correctly.
How often should I clean my flame sensor?
You should clean your flame sensor at least once a year to ensure that it’s functioning correctly. However, if you experience any issues with your boiler, you should consider cleaning the flame sensor more frequently.
What should I do if my boiler keeps shutting off?
If your boiler keeps shutting off, you should call a professional technician to diagnose the issue. It could be caused by a faulty flame sensor, but there could be other underlying issues that need to be addressed.
How can I prevent flame sensor issues?
You can prevent flame sensor issues by having your boiler serviced regularly by a professional technician. Additionally, avoid exposing the flame sensor to moisture or debris, and ensure that the area around the boiler is clean and free of obstructions.
Do I need to call a professional to fix my flame sensor?
While you can attempt to fix some flame sensor issues yourself, it’s always best to call a professional technician to ensure that the job is done safely and correctly. A professional will have the expertise and tools necessary to diagnose and fix the issue.
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