What is a PCB in a boiler?

A boiler PCB is an essential part of any heating system. It stands for printed circuit board and works like the brain or computer of the boiler. Controlling all the other functions within the system. If there’s a problem with your PCB your entire boiler will fail, and it can be costly to replace. In this guide we’ll be exploring more of exactly what a PCB is, how it works, and some common faults that can occur with it. So, you’ll have a better insight into the signs to look out for if you suspect your PCB isn’t functioning properly. 

Defining a PCB boiler part 

The PCB is the centre where the electronic components communicate and work together in synchronisation to provide uninterrupted heating and hot water. It is responsible for maintaining the temperature, pressure, and current flow to ensure the boiler always performs efficiently. Additionally, the PCB is also responsible for safety. So, before the boiler can ignite, the PCB will send a signal to the fan to turn on. The boiler cannot ignite if the fan isn’t working as it is essential for harmful exhaust fumes to be extracted from the boiler. 

When the fan is turned on and running effectively, the PCB can certify that the boiler is safe for operation and the gas valve is then activated. This means the gas can flow into the burner and be ignited so the combustion can occur to produce heat. Alternatively, if the PCB senses that the fan isn’t working, or if there is a fault with the gas valve, thermistor etc. It will tell the boiler not to start up and an error code will be displayed.

How can you tell if your boiler PCB is faulty? 

Being aware of the signs of a faulty PCB is key to getting the problem resolved as quickly and cost effectively as possible. See the boiler PCB faults below. 

Faulty display screen 

If the screen on your boiler is showing broken images or isn’t displaying anything at all, there could be a loose connection between the interface and the PCB. The PCB relies on solid electrical connections between the boiler components. So, when there is a connection problem it can lead to something not working properly. However, a dodgy display won’t always be related to the PCB. Therefore, it’s always best to contact a Gas Safe engineer to check the boiler and find the cause of the fault. 

PCB not communicating with the gas valve 

As mentioned above the PCB works in tandem with the gas valve to generate heat within the boiler. When it has been deemed safe to do so. Once the signal is received that the fan is operational, it is transferred to the gas valve so gas steam can be provided to the burner. If there is an electrical fault between the PCB and the gas valve though, the sequence can be disrupted. This is a serious fault that can result in the boiler malfunctioning or causing a hazard within the home. 

The gas valve and PCB both need to be working properly at all times to maintain the functionality and safety of the boiler. Regular inspections and maintenance can help ensure any potential issues are found and resolved early before they become any worse. If you think there could be a problem with either of these boiler parts, contact an engineer as soon as possible. 

Smell of burning 

A burning smell coming from any electrical appliance in your home is going to be some cause for concern. If it is coming from your boiler, it could be from an internal leak that has led to the circuit board burning. In this case, you must turn off your boiler straight away and contact a professional. If the leak is too severe or your boiler is very old, the best option could be to replace it. But check with your engineer if it is possible to repair the system first.

A memory fault with the PCB 

If you’re getting a memory fault error code on your boiler display screen, it could be a misconfiguration inside the PCB. This can be a fairly common issue if there has been a boiler or PCB replacement. If you have bought a new boiler and are experiencing this issue. You can check the user manual for the right code to re-synchronise the boiler with the PCB and solve the problem. 

PCB wiring problems 

Due to the PCB relying so heavily on electrical connections, if there is a drop in performance it could be because of a loose wire connection. A loose connection can massively impact how your boiler operates. Especially when it’s receiving signals from the fan and sending signals to the gas valve. Any loose wire connections need to be dealt with quickly by a professional to ensure the best possible performance and prevent any hazards from occurring. 

The boiler turns off before reaching its ideal temperature 

If a boiler turns itself off before it has got to the ideal temperature, it’s likely due to a breakdown of communication between the PCB and the thermistor. The thermistor is the part of the boiler that transmits signals to the PCB that accurately state whether the water has reached temperature. If the signals are wrong, the PCB will assume the boiler has got to the right temperature and turn it off. 

Conclusion 

Now that you have a better understanding of what a PCB and the signs to look out for when there is a fault with it. You will be able to easily identify a problem early and contact an engineer to come and repair the issue as quickly as possible. This will save you time and money on further repairs if the problem is left unidentified and worsens. 

If you have an issue with your boiler and need high quality boiler spares and parts that don’t cost the earth, NBS can help. We specialise in cost effective and reliable new and refurbished boiler parts for homeowners across the country. Explore our wide range of products through our online shop to find the exact part you need, no matter the make or model of your boiler. Don’t hesitate to contact us if you have any questions.