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Last updated: 2nd July, 2024


Air Conditioning Unit - Common Errors and Fixes

Air Conditioning Unit - Common Errors and Fixes

Key takeaways

  • Regular maintenance prevents common air conditioning issues.
  • Clean filters and thermostats improve efficiency and lifespan.
  • Professional help is crucial for complex repairs and diagnostics.

Air conditioning systems are vital for maintaining a comfortable indoor environment, especially during the warmer months. It's important to understand the different types and how their components function to ensure proper maintenance and operation.

Experiencing problems with your air conditioning unit during the warm months can be frustrating, especially in the UK's unpredictable climate.

Common aircon errors such as blocked filters, refrigerant leaks, and thermostat issues are frequent culprits. These problems not only affect your comfort but can also lead to increased energy bills and reduced unit lifespan.

Cleaning and maintaining your AC unit regularly can prevent many of these issues. For example, unclogging a blocked drain tube or keeping a filter clean can improve the aircon unit's efficiency.

Proper routine maintenance ensures the unit runs smoothly when you need it the most, helping you avoid costly HVAC repairs in the long run.

In some cases, professional HVAC assistance may be necessary, particularly when dealing with complex issues like refrigerant leaks or damaged coils. Regular check-ups by a certified technician can catch problems early, ensuring your air conditioning system continues to provide reliable comfort.

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Understanding Air Conditioning Units in the UK

Air conditioning systems are vital for maintaining a comfortable indoor environment, especially during the warmer months. It's important to understand the different types and how their components function to ensure proper maintenance and operation.

Types of Air Conditioning Systems

Central Air Conditioners: These systems use a network of ducts to cool multiple rooms. A central unit connects to both indoor and outdoor components.

Window Air Conditioners: Installed in a window frame, these units are suitable for cooling single rooms. They are compact and relatively easy to install.

Portable Air Conditioners: These can be moved from room to room. They typically vent hot air through a window, making them flexible but less efficient.

Ductless Air Conditioners (Split Systems): These types of systems have both an indoor and outdoor unit. The indoor unit mounts on a wall, and it's connected to the outdoor unit by a conduit. This setup is ideal for cooling individual rooms without ductwork.

Floor-Mounted Air Conditioners: These are similar to wall-mounted ductless systems but are installed at floor level, making them a good option for rooms with lower ceilings.

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Components and Functioning

Compressor: Located in the outdoor unit, the compressor circulates refrigerant between the indoor and outdoor units. It plays a key role in the cooling cycle.

Condenser Coils: Also in the outdoor unit, these coils release heat absorbed from inside the home. They convert the refrigerant from a gas to a liquid.

Blower: Found in the indoor aircon unit, the blower distributes cooled air throughout the room. It ensures an even temperature by moving air through the cooling coils.

Cooling Coils: Located in the indoor unit, these coils absorb heat from the indoor air. They are essential for the cooling process.

Capillary Tubing: This controls the flow of refrigerant into the cooling coils. Proper functioning of this component is crucial for efficient cooling.

Regular maintenance, such as cleaning filters and checking refrigerant levels, is vital to keep these components working effectively. Understanding these details can help in troubleshooting and resolving common errors in air conditioning systems.

Common Air Conditioning Unit Problems and Diagnostics (UK)

Air conditioning units in the UK can face various problems such as lack of maintenance, clogged filters, and thermostat issues. Addressing these problems promptly ensures the unit functions properly and efficiently.

Identifying Common Issues

Many air conditioning problems stem from poor maintenance. Dust and debris can clog filters and fans, causing poor airflow or even system breakdowns. Another frequent issue is thermostat malfunction, which might need replacing if it’s not maintaining the set temperature. Water leaks around the indoor unit often indicate a blocked or broken drain tube.

Dirty filters are a common problem. When filters are clogged, the unit struggles to circulate air, reducing efficiency. Electrical issues can also occur, which might make the unit unresponsive or inconsistent in performance.

Initial Troubleshooting Steps

Start by turning off the air conditioning unit to prevent any potential damage. For dirty filters, open the front panel, remove the filters, and wash them with room temperature water. Avoid using detergents as they can damage the filters. Once clean, let them dry completely before reinserting.

If there’s a water leak, check and unclog the drain tube. If the tube is damaged, it will need replacing. For thermostat issues, ensure it’s set correctly. If adjusting the settings doesn’t help, the thermostat might need a replacement.

In cases where simple fixes don’t resolve the issue, it’s advisable to consult a professional. Certain problems like complex electrical faults or persistent mechanical issues require expert intervention to avoid further damage and ensure safety.

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Air Conditioning Unit Maintenance and Regular Care (UK)

Regular maintenance of air conditioning units in the UK ensures efficient operation and a longer lifespan. Maintaining your AC unit involves routine checks, regular cleaning, and knowing when to call a professional.

Routine Air Conditioner Maintenance

Routine maintenance is essential to keep an air conditioning unit operating efficiently. Homeowners should check their units at least once every three months. Simple tasks include checking the thermostat settings, inspecting electrical connections, and ensuring there are no unusual noises.

Filters need regular attention. It's advised to replace or clean filters every month during peak usage. Clogged filters restrict airflow and reduce efficiency. Additionally, inspecting coils for dirt and debris reduces the workload on the system.

Importance of Regular Cleaning

Regular cleaning is crucial to maintain an air conditioning unit's performance. Dust and dirt can clog filters and coils, reducing airflow and efficiency. This not only makes the unit work harder but also increases energy costs.

Clean the filters, coils, and fins to ensure optimal performance. Cleaning the filter is often straightforward. If the filter is reusable, gently dust it. For disposable filters, replace them regularly. Coils should also be free from dust. A dirty coil can't absorb heat effectively, leading to poor cooling.

When to Seek Professional Help

Sometimes, professional servicing is necessary. If basic maintenance does not solve the problem or if the unit still performs poorly, it is time to seek professional help.

Professionals can handle more complex issues, like refrigerant leaks or electrical problems. They are equipped to perform thorough inspections and servicing. Annual professional servicing includes checking refrigerant levels, inspecting for leaks, and testing overall system performance. This ensures the unit runs efficiently throughout the year.

Air Conditioning Unit Specific Issues and Resolutions (UK)

Common problems with air conditioning units in the UK include issues with thermostats, airflow, refrigerants, and electrical components. Each of these problems can impact the efficiency and reliability of the systems.

Thermostat Problems

Thermostat issues often arise from improper settings or faulty hardware. Incorrect settings can cause the system to run continuously or not at all. Sometimes, a simple recalibration or resetting of the thermostat can fix these problems.

If the thermostat is unresponsive, replacing the batteries might help. For programmable or smart thermostats, ensuring that the software is updated can prevent glitches. When adjusting settings does not resolve the issue, a technician may be needed to inspect for wiring faults or replace the unit.

Airflow Issues

Airflow problems can significantly reduce the overall efficiency of an air conditioning unit. Clogged filters are a common cause, restricting air entry, which makes the system work harder and increases energy consumption. Regularly replacing or cleaning filters can prevent this issue.

Blocked vents and registers can also impede airflow. Ensuring that these are open and unobstructed helps maintain proper air circulation. Another common problem is a dirty air filter, which can be remedied by regular maintenance. If airflow issues persist, it may be necessary to consult a technician to check for more serious issues such as duct blockages.

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Refrigerant and Leak Repairs

Low refrigerant levels or refrigerant leaks can cause the air conditioner to struggle with cooling. Signs of low refrigerant include uneven cooling or the unit blowing warm air.

A refrigerant leak needs immediate attention by a qualified technician. Refrigerant leaks can be hazardous and require careful handling. A technician will typically repair the leak and recharge the refrigerant levels to the required specifications. Regular inspections help identify and address leaks before they become problematic.

Electrical Component Failures

Electrical problems can be tricky to diagnose and often require professional expertise. Common issues include faulty wiring, blown fuses, and tripped circuit breakers.

Electrical issues may cause the system to shut down unexpectedly or fail to start. Checking circuit breakers and fuses can sometimes reveal the problem. If these components are frequently failing, it may indicate deeper electrical faults requiring the attention of a technician. Regular maintenance helps identify potential electrical faults early, avoiding sudden breakdowns and ensuring the longevity of the system.

Upkeep for Efficiency and Longevity

Maintaining your air conditioning unit is crucial for ensuring it works efficiently and lasts as long as possible. Proper upkeep can also help you save on energy bills and prevent costly repairs.

Energy Efficiency Tips

To keep your air conditioning unit operating efficiently, it's important to pay attention to several key maintenance tasks. Firstly, regularly cleaning or replacing the air filter can significantly enhance performance and efficiency. A dirty filter forces the unit to work harder, consuming more energy and increasing your bills.

Next, ensure your system's coils are clean. Coils can absorb heat more effectively when they are clean, leading to better efficiency. Use a soft brush or vacuum to gently remove dirt and dust from the coils.

Sealing any leaks in the ducts is also essential. Leaks can reduce the efficiency of your unit by allowing cool air to escape. Proper insulation of ducts helps maintain the desired temperature, requiring less energy.

Lastly, adjusting the thermostat settings can make a big difference. Keeping the thermostat set a few degrees higher in the summer can reduce energy usage without significantly affecting comfort. Consider using a programmable thermostat for more precise control over your cooling needs.

Extending Your Unit's Life

To extend the lifespan of your air conditioning unit, regular maintenance is key. Scheduling annual professional inspections can catch potential problems early before they become major issues, saving you both money and hassle.

Keep the area around your outside unit clear of debris and plants. Obstructions can block airflow, causing the unit to overheat and work less efficiently. Regularly check that there is at least a metre of clear space around the unit.

Ensuring a stable power supply is crucial. Fluctuations or surges in electricity can damage the unit's components. Using a surge protector can help shield your air conditioner from unexpected power spikes.

Regularly checking and tightening electrical connections can prevent operational issues. Loose connections can lead to more serious problems and reduce the unit's efficiency.

Finally, avoid overworking your unit. Properly insulating your home and using shades or curtains to block direct sunlight can reduce the load on your air conditioner, helping it to last longer while maintaining comfort inside.

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Advanced Air Conditioning Unit Care (UK)

Proper care of an air conditioning unit in the UK involves handling extreme weather conditions, upgrading and replacing parts, and integrating smart controls and automation systems.

Handling Extreme Weather Conditions

Extreme weather can put a strain on an air conditioning unit. In winter, ensure that the unit's heating function is efficient. Regularly inspect the external unit to remove any snow or debris.

Use a cover to shield the unit from harsh weather. During summer, hot sunlight can lead to overheating. Place the unit in a shaded area and clean the filters frequently to maintain airflow.

Investing in a unit with a high Seasonal Performance Factor (SPF) can also be beneficial for energy efficiency. Make sure that cooling systems are not overwhelmed by extended periods of use in high temperatures.

Upgrading and Replacing Parts

Over time, parts of the air conditioning unit may need to be upgraded or replaced to maintain peak performance. Start with the filters, as they often get clogged. Clean or replace them every three months. Coils and fins also accumulate dirt and should be cleaned regularly.

For significant upgrades, consider inverter technology which adjusts the motor speed to save energy. When replacing old parts, opt for high-quality materials to prolong the unit's lifespan. Keep an eye on refrigerant levels and replace older refrigerants with more environmentally friendly options.

Smart Controls and Automation

Integrating smart controls and automation into an air conditioning unit can significantly enhance user comfort and energy efficiency. Smart thermostats, for instance, allow users to control the unit remotely through smartphone apps. These systems can be programmed to adjust the temperature based on daily routines.

Automation helps in managing the unit more effectively, resulting in lower energy bills. Sensors can detect the room’s occupancy and adjust the cooling or heating accordingly. Furthermore, smart units can provide alerts for necessary maintenance, ensuring the unit is always in excellent condition. Automation adds a layer of convenience and optimizes the unit’s performance efficiently.

Professional Services and When to Engage Them (UK)

Engaging professional services for air conditioning maintenance can save homeowners both time and trouble. Qualified experts ensure efficient and effective repairs, preventing small issues from turning into costly problems.

Selecting a Qualified HVAC Professional

When looking for an HVAC professional, it's key to verify their qualifications and experience. Start by checking certifications and credentials that show the technician or engineer's expertise.

Look for accreditations from recognised bodies like the Air Conditioning and Refrigeration Industry Board (ACRIB) or the Chartered Institute of Building Services Engineers (CIBSE).

Client reviews and recommendations can reveal the reliability and skill of a service provider. It's also beneficial to confirm that the technician has experience with the specific make and model of your air conditioning unit.

Understanding Service Costs

Service costs can vary widely depending on the complexity of the task and the professional's expertise. Basic maintenance like filter cleaning can be relatively inexpensive. In contrast, more intricate repairs such as addressing refrigerant leaks or motor issues might cost significantly more.

Service Type: Regular maintenance, emergency repairs, or full system installations affect pricing. Regular maintenance is generally cheaper and can prevent the need for costly repairs.

Location: Rates can differ across regions in the UK, with urban areas potentially charging more.

Collect quotes from multiple professionals to compare rates and services offered. Be wary of unusually low prices, which might indicate a lack of experience or hidden costs. Consider the value of investing in quality service to ensure long-term savings and efficiency.

Resolution of Specific UK Brands Issues

In the UK, Daikin, Fujitsu, and Panasonic are popular air conditioning brands. Each brand has unique features and potential problems that require specific resolutions. This section provides detailed troubleshooting, addressing common issues, and maintenance tips for each brand.

Troubleshooting Daikin AC Units

Daikin air conditioning units are known for their reliability and advanced features. Nonetheless, users may face problems such as the unit not turning on, reduced cooling, or unusual noises. Begin by checking the power supply and ensuring that the circuit breaker hasn't tripped. Verify that the thermostat is set correctly and clean or replace the air filters if they are dirty.

If the unit is still not working, inspect the external unit and clear any debris that might be blocking airflow. In cases where the unit makes unusual noises, it could indicate a problem with the fan or motor.

Ensure these components are securely in place and not damaged. For persistent problems, contacting a professional technician might be necessary.

Addressing Fujitsu System Problems

Fujitsu systems are valued for their energy efficiency and quiet operation.

However, problems like insufficient cooling, water leakage, and error codes can occur. Start by cleaning the air filters and checking the outdoor unit for obstructions. Ensure the thermostat is set to the desired temperature and that all vents are open and unobstructed.

Water leakage often indicates a blocked drainage pipe or full drain pan. Inspect these components, clear any blockages, and ensure proper drainage. If error codes appear on the display, consult the user manual to identify the issue.

Resetting the system by turning it off and on again might resolve minor glitches. Persistent or severe issues should be handled by an authorised service provider.

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Panasonic Air Conditioners Maintenance

Panasonic air conditioners are appreciated for their durability and innovative technology. Regular maintenance is key to preventing common issues like poor airflow, unpleasant odours, or system malfunctions. Cleaning the air filters every few months helps maintain efficient airflow and can prevent many problems.

Make sure to keep the outdoor unit free from obstructions and debris.

For unpleasant odours, the coils and evaporator should be cleaned to ensure there is no mould or mildew buildup. If the unit fails to cool properly, check the refrigerant levels and replenish if necessary, but this should be done by a professional.

Keeping the unit well-maintained can extend its lifespan and ensure optimal performance.

By following these specific troubleshooting and maintenance steps, users can effectively manage and resolve common issues with Daikin, Fujitsu, and Panasonic air conditioning units.


Regular maintenance can significantly reduce the chances of air conditioning problems. Simple tasks like cleaning or replacing filters can prevent many issues and improve efficiency.

Checking the thermostat is also essential. Ensure the batteries are working and the set point is correctly adjusted for proper cooling or heating.

Water leaks often signal a blocked or broken drain tube. Addressing this promptly can prevent damage and maintain system performance.

Professional inspections and adjustments help maintain the unit's lifespan. A scheduled service can catch potential problems early.

For those in the UK, local experts are available to offer professional advice and service. Don't hesitate to reach out for complex issues that require specialised knowledge.

By following these guidelines, homeowners can ensure their air conditioning unit runs smoothly, offering comfort during hot and humid months. Stay proactive to avoid costly repairs.

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Frequently Asked Questions

Do aircon units use a lot of electricity?

Air conditioning units can vary in their electricity consumption based on size, model, and usage patterns. Modern units tend to be more energy-efficient compared to older models. It's important to look at the unit's energy efficiency rating before purchase.

Are air conditioning units expensive to run?

Running costs depend on factors like the unit's efficiency, how often it's used, and local electricity rates. High-efficiency units typically cost less to run than older, less efficient ones. Regular maintenance can also help keep running costs down.

Do all portable air conditioners have to be vented out a window?

Most portable air conditioners need to be vented to expel hot air from the room. This usually involves a hose that must be connected to a window or another type of opening. There are some ventless models, but they often use evaporation and are less effective.

How much does it cost to get AC in the UK?

The cost of installing air conditioning in the UK can range from £500 for a small portable unit to several thousand pounds for a central system. Installation costs can vary based on the complexity of the setup and the type of unit chosen.

Is it legal to install air conditioning in the UK?

Yes, it is legal to install air conditioning in the UK. However, you may need planning permission if you live in a listed building or a conservation area. It's always a good idea to check local regulations before installing a unit.

How to cool down a room without AC?

You can cool down a room by using fans, closing blinds or curtains to block sunlight, and keeping windows open at night to let cooler air in. Insulating your home and using reflective window films can also help reduce indoor temperatures.

What is the cheapest way to cool down a room?

The cheapest ways to cool a room involve using ceiling fans or portable fans to circulate air. Closing curtains during the hottest parts of the day and using a damp cloth on your neck can also provide quick relief without running up your electricity bill.

Stephen Day profile photo
Article by
Stephen Day | Co-founder
Gas Safe registered and FGAS certified engineer with over 20 years experience in the heating and cooling industry.