How to Fix F9 Fault Glow-worm?

When your boiler displays the F9 fault code, it can cause concern. For homeowners relying on their Glow-worm boiler for heating and hot water, understanding what this code means and how to address it is essential. In this post, we'll explore the meaning of the F9 fault, its common causes, and practical solutions to get your boiler back in working order.

What is the F9 Glow-worm Fault?
[LOW PRESSURE]

The F9 fault code on a Glow-worm boiler indicates a problem with the water pressure sensor.

This sensor is crucial for maintaining the correct water pressure within the boiler system. When the pressure sensor fails or detects incorrect readings, the boiler will display the F9 error code to prevent further issues.

This code alerts the homeowner to a potential problem that needs immediate attention. Ignoring the F9 fault can lead to more significant issues, such as boiler breakdowns or damage to the heating system.

Water Pressure in Heating Systems. Water Vs Gas

Regarding heating systems, terms like "boiler pressure" or "system pressure" are essential. These terms are especially important when addressing issues like the Glow-worm F9 fault.

For your Glow-worm boiler to function properly, water needs to flow from the main supply to the boiler at an adequate rate, which requires sufficient pressure. If the water volume in the pipes is low, the flow rate decreases, slowing down the circulation in your central heating system.

Potential Issues with Low Water Pressure

• Reduced Tap Flow: You may notice that water comes out of your taps more slowly than usual.
• Overheating Risks: While the boiler might generate the correct amount of heat, inefficient water circulation can prevent proper heat transfer, causing the boiler to overheat.
• System Shutdown: The boiler includes safety measures to avoid severe damage or dangerous situations,. If it detects potential problems, it will lock out and display a fault, such as the F9 code.

To keep your heating system running smoothly, it's crucial to maintain the correct pressure.

What Causes F9 Error Code in Glow-worm Boilers?

Understanding how the F9 error occurs can help in diagnosing and fixing the issue.

Low or high water pressure can trigger the F9 fault. If the system pressure falls outside the recommended range, the boiler cannot operate safely.

Leaks in the system can cause a drop in pressure, leading to the F9 error.

Blockages or airlocks in the system can also affect the water pressure, causing the sensor to detect unusual readings.

Boilers often lose pressure over time and usually need to be re-pressurized annually.

Bleeding your radiators can lead to pressure loss if too much water escapes. If this happens, re-pressurizing can resolve the issue.

Over time, the pressure sensor may wear out or become faulty, leading to incorrect readings. Electrical connections to the sensor might become loose or corroded, affecting its performance.

Problems with other internal components, such as the PCB (Printed Circuit Board), can indirectly cause the F9 fault code.

Debris or limescale buildup within the boiler can also interfere with the sensor's ability to function correctly.

Increasing the pressure in your central heating system can fix the F9 fault code. This is typically a simple, inexpensive task that doesn't require a gas-safe engineer.

For more information on boiler faults, check out our blog section on boiler error codes.

How to Fix the F9 Fault in a Glow-worm Boiler?

Fixing the F9 fault code involves several steps, depending on the underlying cause.

Here are some practical solutions to address this issue.

Optimal boiler pressure

Start by checking the boiler's pressure gauge. The ideal pressure should be between 1 and 1.5 bars. If the pressure is too low, you can increase it by adding water to the system using the filling loop. Consult your boiler's manual for specific instructions on this process.

If the pressure is too high, bleeding the radiators can help reduce it. Use a radiator key to release excess air and lower the pressure.

Examine your boiler and the surrounding area for any signs of water leaks. Fixing leaks promptly can prevent pressure drops.

Check all visible pipes, radiators, and joints for leaks. If you find a leak, it may be best to call a professional for boiler repairs.

Sometimes, resetting the boiler can clear minor faults. Refer to your boiler's manual for instructions on how to perform a reset.

After resetting, monitor the boiler to see if the F9 fault code reappears.

If the pressure sensor is dirty or faulty, it may need cleaning or replacement.

• Turn off the boiler and allow it to cool before attempting any maintenance. Disconnect the electrical connections to the sensor and inspect it for dirt or damage.
• Use a soft brush or cloth to clean the sensor. If it appears damaged or worn out, consider replacing it with a new one.
• Use a soft brush or cloth to clean the sensor.

In some cases, the F9 fault code may persist even after adjusting the water pressure and resetting the boiler. This often indicates a faulty pressure sensor that requires replacement.

Replacing a Faulty Pressure Sensor

Locate the pressure sensor within the boiler. Refer to the boiler's manual for its exact position. Use a multimeter to test the sensor's electrical connections. If the readings are inconsistent or outside the expected range, the sensor is likely faulty.

• Purchase a compatible pressure sensor for your Glow-worm boiler model. Make sure it meets the specifications outlined in the manual.
• Turn off the boiler and isolate the power supply. Remove the faulty sensor by disconnecting the electrical connections and unscrewing it from its position.
• Install the new sensor and reconnect the electrical connections. Turn on the boiler and check if the F9 fault code has cleared.

While some homeowners may feel confident in handling minor boiler repairs, others may prefer the expertise of a professional. Calling a gas-safe engineer ensures that the F9 fault is diagnosed and repaired safely and efficiently.

Why Choose a Gas Safe Engineer?

Gas Safe engineers are certified professionals trained to handle boiler repairs and maintenance. They have the necessary knowledge and tools to diagnose and fix complex issues, ensuring your boiler operates safely.

The heating engineer will conduct a thorough inspection of your boiler, including checking the pressure sensor and other internal components.

They will diagnose the root cause of the F9 fault and provide a detailed explanation of the required repairs.

The engineer will carry out the necessary repairs, such as replacing the pressure sensor or fixing leaks. They may also perform routine maintenance to prevent future issues and ensure the boiler operates efficiently.

An annual boiler service is an excellent way to extend your boiler's lifespan and minimize potential issues.