How to Fix Glow-worm F75 Fault Code?

A boiler breakdown can quickly turn your cosy home into an uncomfortable space, especially during colder months. If you see the F75 fault code on your Glow-worm boiler, you're likely dealing with interrupted heating or hot water supply.

This guide will explain the F75 code, its causes, and the steps you can take to resolve the issue. Whether you're a hands-on homeowner or prefer to call the experts, we've got you covered.

Glow-worm Boilers

Glow-worm is a trusted name in domestic heating, and it is known for producing reliable and energy-efficient boilers. However, like any appliance, boilers are prone to faults over time, and error codes like the F75 are designed to alert you to specific issues.

What is the F75 Fault Code?
[PRESSURE SENSOR ISSUE]

The Glow-worm F75 error is a sign that the boiler's pressure sensor isn't working properly.

This sensor has an important job—it keeps an eye on the water pressure moving through your boiler system. It sends this information to the boiler's PCB, which is like the brain of the boiler, controlling how everything runs.

Water pressure is simply the force pushing water through the pipes. The amount of water in the system influences it, which also affects how fast it flows.

When water heats up, it's normal for the pressure to rise a bit, and the PCB keeps an eye on this to ensure it stays within safe limits. This lack of pressure change suggests either a problem with the sensor, the pump, or the water pressure in the system.

Key symptoms of the F75 fault code

• An error code is displayed on your boiler's screen.
• Interrupted heating and hot water supply.
• Unusual noises, such as gurgling or banging, from the boiler.

Always ensure you get boiler support from a certified boiler repair service.

What Causes the Glow-worm F75 Fault?

The F75 fault code typically stems from one of three primary underlying issues:

This sensor is a crucial role in monitoring the water pressure within your boiler system, ensuring everything runs smoothly.

If the sensor fails to detect changes in pressure, your boiler will automatically shut down and display the F75 error code as a safety measure.

When this happens, the sensor may stop working altogether, leading to the same F75 fault. One early sign of a faulty pressure sensor is that the pressure gauge on your boiler doesn't show an increase as the heating process starts. However, if the boiler's PCB (its control centre) is functioning correctly, the F75 error will likely appear before you even notice this issue on the pressure gauge.

In either case, the F75 error serves as a prompt to address the problem and get the pressure sensor back in working order.

An F75 error on your boiler often points to issues with water circulation, and the heat pump is crucial in this process. The pump is responsible for moving water throughout your heating system, creating the necessary pressure changes for everything to function smoothly.

If the pump isn't working properly, the PCB (the boiler's control centre) cannot detect the correct water pressure flow, triggering the F75 error.

So, what could cause the heat pump to malfunction?
There are a few possibilities:

• Wear and Tear or Airlocks: Over time, pumps can degrade, or airlocks can form, disrupting their operation.
• Sludge Buildup: Blockages caused by sludge can lead to airlocks and ultimately prevent the pump from working.
• Worn Bearings: In older pumps, bearings may have deteriorated to the point where they fail completely.
• Incorrect Speed Settings: In newer or recently repaired pumps, the speed settings might not be properly configured, impacting performance.

Signs Your Heat Pump Might Be Faulty

If your heat pump isn't functioning efficiently, you might notice some telltale signs, such as:

• A vibrating sound when the boiler powers up.
• Unusual noises like clanging or banging.
• Components like the pump's shaft or bearings become stuck, which can stop the pump entirely.

Each of these issues can prevent the heat pump from circulating water effectively, leading to problems with your heating system. If you suspect a heat pump issue, it's essential to address it promptly to restore your boiler's efficiency and avoid further complications.

Low water pressure is another possible cause of the F75 error, though it's less likely to be the sole reason. This issue can happen due to leaks in the system, not topping up the water properly, or problems with the filling loop.

Typically, the water pressure in a boiler decreases gradually over time. While low pressure might suggest an underlying issue—like a boiler leak, a system leak, or a faulty component—it doesn't always mean something serious is wrong.

That said, when the F75 error is linked to low pressure, it's usually accompanied by a malfunctioning pressure sensor. The sensor's failure to accurately monitor water pressure can trigger the error, even if the pressure itself isn't the primary issue.

So, if you're dealing with low water pressure, it's essential to see the bigger picture and address any related problems for a proper solution.

How to Fix the Glow-worm F75 Fault?

Fixing the F75 fault code requires a clear understanding of the issue at hand. Below, we've outlined steps to troubleshoot and address the problem.

Can I Fix the F75 Fault Code DIY?

While some boiler repairs are best left to professionals, there are two things you can try before calling an expert:

Sometimes, a system reset can resolve minor glitches. Follow these steps to reset your Glow-worm boiler:

• Press and hold the power button for 5 seconds.
• A cross-like symbol should flash on the screen as the boiler restarts.

Once restarted, check whether the F75 error code has disappeared. If it has, monitor your boiler to ensure it's working correctly.

If your boiler's water pressure is too low, you can manually repressurise it.
Here's how:

• Locate the filling loop on your boiler.
• Open the valves and allow water to flow into the system until the pressure gauge reads between 1.0 and 1.5 bar.
• Close the valves and check whether the fault persists.

Check out our blog on 'How to Fix a Boiler Leak' for helpful tips and solutions!

When to Call a Professional?

For complex problems like a blocked sensor or faulty heat pump, it's crucial to enlist a Gas Safe registered engineer.

Serviceteam Boiler Repair Service

At Serviceteam, we specialise in diagnosing and fixing boiler faults like the F75. Our experienced engineers are fully certified and equipped to handle the toughest repairs.

Why Choose Serviceteam?

• Accurate Diagnosis
  Our experts use industry-leading tools to identify the root cause of the F75 fault quickly and accurately.
• Attempt to Fix Within the First Hour
  We aim to resolve the issue promptly, getting your boiler back in working order as fast as possible.
• Fixed Price Quotes
  With transparent pricing starting from £104 + VAT, there are no hidden surprises.
• Gas Safe Registered
  Your safety is our priority. All heating engineers at serviceteam are Gas Safe registered, ensuring your boiler is serviced with the highest level of expertise and care.

Based in London? We're just a call away for same-day emergency boiler repairs. No matter the time, our team is on hand to restore warmth to your home.

How to Prevent Future F75 Faults?

To avoid encountering the F75 error in the future, consider the following preventative measures:

• Schedule annual boiler servicing to ensure all components are clean and functional.
• Regularly check your boiler's water pressure and top-up as needed.
• Use magnetic system filters to prevent debris from clogging the pump or sensor.
• Add a water softener if your area has hard water to reduce limescale buildup.

Serviceteam also offers affordable boiler servicing packages to keep your system in excellent condition year-round.

Take Action Today!

The Glow-worm F75 fault code might seem daunting, but it's a manageable issue with the right approach. While minor fixes like resetting the boiler or repressurising it can be done DIY, most cases require the expertise of a qualified engineer.

Don't put off keeping your home warm and your water running. Contact Serviceteam for fast, reliable boiler repairs with fixed pricing and exceptional service.

Explore our boiler error code blog section to learn everything you need to know about boiler error codes!