Air conditioning troubleshooting

A faulty air conditioning system is the last thing you want to deal with when the summer arrives. From leaky refrigerant to strange noises, it’s good to know what to do for each problem.

Knowing what to do at the first signs of trouble could mean you save on hefty repair bills.

Here are some possible air conditioner problems and solutions.

Air conditioner is not turning on

It can be a headache if your air conditioning system doesn’t turn on. But don’t panic just yet. Here are some things to try if your AC is not working:

Check the thermostat batteries

If they are dead, replace them. If the batteries are in working condition, make sure the thermostat is in cooling mode and set to your desired temperature. If your thermostat is broken, it’s time to get it replaced by a professional.

Check the air filter for a build up of dirt and debris

Dirty filters can impact airflow, causing your air conditioner to freeze and not turn on. Your filter should be changed once a month or every other month, depending on the number of pets and people living in your home.

Check the circuit breaker to see if it’s accidentally tripped

To resolve this issue, flip the switch so that it’s in the ON position. If your AC continues to trip the breaker, it could be a bigger problem, so contact an AC expert as soon as possible.

Reset the AC unit if your system has a reset button

Alternatively, manually reset your air conditioner by switching the thermostat off for five to 10 minutes before turning it back on again.

Inspect for ice build up either on or inside the unit

If you find ice on your machine, wait for it to defrost before restarting the unit. If you do see ice on your air conditioner, we recommend calling an air conditioning specialist to prevent any damage from occurring.

Air conditioner not blowing cold air but running

There are several reasons why your air conditioner unit might be running but AC not blowing cold air.

Thermostat issues

One of the most common reasons why an air conditioner system might be running but not cooling a house is due to thermostat issues.

Action: Check your thermostat settings and try adjusting the temperature up or down to see if that helps. Does it need to change from cooling to heating? You can also try cleaning the thermostat and replacing the batteries.

Low refrigerant levels

Refrigerant is the substance that your AC unit uses to cool the air, and if there’s not enough of it, your air conditioning won’t be able to function correctly.

Check if your AC unit is running low on refrigerant. This can happen if there’s a leak somewhere or if something is obstructing one of the valves.

Action: Fix the problem by topping up the refrigerant or calling a professional to look at the issue. If you’re not sure how much refrigerant you need, an air conditioning specialist can inspect your system and tell you exactly what needs to be done.

Dirty air filters

Air filters are designed to trap dust, dirt, and other contaminants and prevent them from circulating around your home. Over time, however, they can clog with debris or blockages, making it more difficult for cool air to circulate.

Dirty filters can cause several problems for your AC system, including reduced airflow, increased energy consumption and decreased cooling efficiency.

Action: Replace your air filters regularly with new ones made specifically for your unit. If there isn’t much visible dirt on your current disposable filter, clean off as much dust as possible before putting it back into place.

Faulty condenser or evaporator coils

The condenser coil is responsible for removing heat from the refrigerant, while the evaporator coil is responsible for cooling the air that circulates through your home.

If these coils are dirty or damaged, your air conditioner may run but not cool your house. This is because the coils cannot transfer heat and cool the air effectively.

Action: Call a professional. Cleaning or repairing condensers and coils is a job best left to a professional HVAC technician. They have the experience and equipment needed to diagnose and fix any issues. Sometimes, they may recommend replacing the parts entirely if they’re beyond repair.

Wrong size of AC unit

AC not cooling? Perhaps you have the wrong size of AC unit?

An oversized unit can be too powerful for your home and lead to short cycling. In turn, the unit will turn on and off frequently, increasing wear and tear and decreasing efficiency.

On the other hand, an undersized unit my struggle to cool your home effectively – especially during hot days and heat waves.

Action: Consult a professional air conditioning specialist who can look at the size of your home and the number of people living there. They can then recommend the right size of unit for your needs.

Air conditioner is leaking

It’s not uncommon to see drops of water coming from an AC unit. But what causes air conditioning to drip, and how do you stop it?

Here are some of the most common reasons:

• The AC filter is blocked: A blocked filter can cause a build-up of pressure and cold air inside the unit, therefore causing an unwanted leak. Clean your filter regularly to avoid this
• Damaged pipes: Cracked, rusted or weathered pipework can result in an AC leak. Check your air conditioning pipes for any signs of damage. Contact an air conditioning specialist for any repairs
• Cold temperatures outside: In the winter, extreme cold temperatures can often cause air conditioning leaks. This is because less water evaporates and can build up inside the unit and then start to leak. Put a cover over your AC unit to reduce the effect of cold temperatures
• Clogged condensation line: The condensation line allows water to drain from your AC unit via a small pipe. Over time, dirt or mildew may clog the line. Clean the indoor line in the AC unit with bleach mixed with warm water
• Frozen AC coil: If set too low, the thermostat on your AC unit could cause your air conditioning coil to freeze and/or create a build-up of ice. Change your filter regularly and check the AC thermostat and condensate drain regularly

A dripping AC unit may also be caused by a faulty component. An experienced air conditioning specialist should investigate as soon as possible.

For more information, check out our guide on everything you need to know about air conditioning.

Air conditioner is freezing up

One of the reasons your AC unit may not be working properly is that it keeps freezing up.

Freezing can be seen within the evaporator coil, or on the exterior of the outside unit (the condenser coils). You might see a thin layer of ice due to frost having built up on the refrigerant lines.

It could be down to one of these issues:

Poor airflow: If the air filter is dirty or too many vents are closed it can block good airflow throughout the system. Hence the AC unit can freeze up with the refrigerant condensing on the coils.

Setting is too cold: When the outside temperatures are cool the air pressure won’t work correctly. It’s a good idea to install a smart thermostat so you can work out what temperatures work best – and adjust accordingly.

Refrigerant levels are not right: If your AC system is too low or too high on refrigerant it could cause the temperature of your evaporator to drop, freezing moisture and icing up the system. Call an air conditioning expert if you think this is due to a refrigerant leak.

Air conditioner making strange noises

An air conditioner can make different sounds depending on the type of problem. These noises often indicate it’s time to repair or replace your unit.

Here are some of the most common air conditioner noises that you should not ignore.

There are different reasons why your air conditioner is producing a variety of sounds:

• A refrigerant leak can produce a hissing sound
• If you hear clicking sounds when you turn on and off your AC, it might be a relay problem
• Thumping, rattling, or banging noises mean there is a problem with a blower or motor assembly
• A screeching noise usually means a malfunctioning fan motor
• Faulty electrical components produce a buzzing sound

If your air conditioning unit is making any unusual sounds, get in touch with an air conditioning expert in your area who can help fix the issue.

FAQs

What does an air conditioning unit service consist of?

An air conditioning service will consist of a thorough clean of the system’s components, such as the filters, coil, fan, and drain pan.

It’s a good idea to get your air conditioning system serviced regularly to keep it in good working order.

How often should a home air conditioner be serviced?

Conditions vary greatly between industrial buildings, offices, and residential properties. Each situation will need to be evaluated individually. Generally speaking, we recommend getting it checked at least once per year.

How much does it cost to service an air conditioner?

Air con maintenance will cost around £30 - £60 per hour for the labour, plus the cost of any refrigerant required. This can cost between £35 - £130.

Is an air con service worth it?

The benefits of an air con service are that the unit will perform more efficiently, and any problems will be spotted early, which could save you money in the long run.

How much does it cost to install air conditioning?

Take a look at our air conditioning cost guide for information on costs.

If you’ve got an issue with your air conditioning, our experts can help. Pop your postcode in the search bar below and find local professionals.