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Boiler PCB Faults – Repairs, Costs & More

Boilers can shut down for many reasons but if the PCB is the cause a Gas Safety engineer will be needed to confirm the specific concern with the part due to the location of the PCB within the boiler.

The engineer will be able to test and diagnose the technical part, making any recommendations for repairs or a replacement.

In this guide, we will run through the function of the PCB within modern boilers, explore the common faults with a PCB and the typical path of action in each scenario.

Here’s what a PCB looks like:

Printed Circuit Board

What is the PCB?

The printed circuit board or PCB is technically the brain within the boiler, communicating and controlling all of the electrical components inside.

The PCB performs many tasks from starting processes such as turning on the fan and igniting the boiler as well as running safety checks in the background.

These safety checks are constantly checking that each of the boiler components is working correctly, and if a fault is detected the boiler will deliberately shutdown to minimise further damage to the boiler itself and protect the property.

However, like any other internal part, the PCB can become faulty and cause a breakdown of the boiler that was not intended or needed.

If you need to reset your boiler too often, it may be a sign of a more significant fault, such as a faulty PCB, a boiler leak or a central heating pump problem, and if your boiler isn’t igniting, it may be time to consider getting a new boiler quote.

What steps should be taken if a faulty PCB is suspected?

Firstly, the PCB is located within the boiler unit itself, and therefore the boiler casing should not be removed by anyone other than a profession Gas Safe Engineer as it can be dangerous. If a problem is suspected with the PCB, contact a Gas Safe engineer to provide assistance and diagnose the concern whilst putting in a plan to resolve the matter.

If the boiler has stopped working and has displayed an error code within the display window of the unit, this could lead to further information about the cause of the breakdown. The boiler undertakes the shutdown process to protect the internal components from any further damage and to keep the property safe, as well as anyone living within the property.

Error codes are often provided when the boiler recognises the fault. To find the description behind the error code for your boiler make and model, refer to the boiler’s manual or the manufacture’s website. However, with most technical issues, always seek the advice of a Gas Safe engineer before trying any troubleshooting yourself.

Common Signs of a Faulty PCB

As discussed already, there can be many causes of a boiler breakdown however there are some common signs that the PCB could be at fault and these include the following:

Display panel not working

If the display panel is not lighting up or is intermittent this may be a sign of a loose connection between the PCB and display interface. A Gas Safe engineer would be required to investigate any connection issues, making any repairs or replacing parts as needed.

Boiler making a burning smell

If a burning smell is coming from your boiler along with performance issues this could be a sign of a leak inside the boiler which may have caused the PCB to burn. In this scenario, a Gas Safe engineer would need to be called to confirm the diagnosis and locate the source of the leak. Depending on the parts involved would determine the repair costs. If there was significant water damage to the PCB or other parts, a replacement boiler may be more economical

No power to the PCB or display panel

If the PCB or display panel shows no signs of power at all then a Gas Safe engineer would need to be called out to investigate the matter. If the PCB has failed completely it is likely that the part would need replacing.

Sometimes PCB’s can be repaired however often due to the amount of engineer’s time needed, it is often more financially viable to replace the PCB in its entirety.

PCB memory fault

When an error code is being displayed within the boiler display window indicating that there is a memory fault, the PCB may require resetting. This sometimes happens shortly after a new boiler is installed or following a PCB replacement.

In this case, refer to the boilers manufactures’ manual to find the instructions of how to reconfigure the PCB along with any product codes required.

PCB wiring issues

There are many electrical wires inside a boiler, linking parts back to the PCB and therefore there are lots of opportunities for wires to become loose.

If wires become loose, parts may become intermittent or stop working altogether. In addition, the safety mechanisms built into the boiler will shut down the boiler should a connection not be established to crucial parts.

Any suspected wiring issues will require a Gas Safety engineer to work safely inside the unit and assess the wiring concerns making repairs where possible or providing quotes for replacements if needed.

What causes a faulty PCB?

The most common cause of faults with the PCB is the age of the unit itself as the technology ages and begin to incur faults. Boilers also have many moving parts which over time become worn and therefore require replacing.

As with any boiler repair and replacement advice, always consider the age of the boiler before proceeding with costly repairs as it may be more cost-effective to replace the entire boiler and benefit from the energy efficiencies of modern A-rated boilers.

Water damage to the PCB

As is well known, water and electrics should not be mixed and therefore if a leak is experienced significant damage can be incurred to the PCB. Leaks can occur for many reasons such as wear or tear or parts, pressure issues or blockages causing damage.

All water damage issues will require immediate attention from a Gas Safety engineer.

Is your boiler losing power? Or is your boiler pressure too high? If your boiler is old, past its warranty, it may be time for a new boiler replacement.

Boiler vibrations

A boiler may vibrate slightly when in use, however, increased vibrations may be a sign that something isn’t quite right. Excessive vibrations can be a symptom of a fault, however, the movement itself can cause damage to parts.

If any changes in boiler vibrations are noticed, specialised assistance should be sought.

How much will a new PCB cost to replace?

A boiler’s PCB is one of the most expensive components within the boiler. The exact cost will be dependent on the make and model of the boiler.

However, the approximate cost is usually around £500. Due to the high costs involved, it’s always worth asking if a replacement boiler is more cost-effective.

Replacing a PCB

The process of replacing a PCB can take an engineer a couple of hours once a part is located. Bear in mind, a replacement PCB may take some time to source, particularly if you have a very dated boiler model, and worse still it may no longer be available if your boiler’s ancient.

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