Skip to Content

Fujitsu Ducted Air Conditioner: Troubleshooting Guide

Fujitsu ducted air conditioners are an excellent way to cool your home during the scorching heat of summer. They are cost-efficient and distribute heat evenly, lowering your electricity bills. However, without proper maintenance, these systems can malfunction, making it impossible for them to serve their intended purpose. 

If your Fujitsu ducted air conditioner isn’t working, check to see the ductwork is sealed correctly, that dirt or stray objects aren’t blocking the vents, that the air filter is clean, and that the duct system itself is clear of clogs. 

This Fujitsu ducted air conditioner troubleshooting guide addresses some of the issues you are likely to encounter with these cooling systems and how to fix them to get your unit working again. Let’s get into it.

How a Ducted Air Conditioner Works

A ducted air conditioning unit works by channeling cold air from a central unit to your home through a network of ducts. The central unit is usually located on your roof. The cold air released from the unit travels through the ducts to every room in your house, where it is blown out through the air supply vents. 

Air circulation is zoned, which allows you to control the flow of air to different rooms. This helps minimize running costs and enables you to enjoy the most comfortable temperatures based on your specific needs. 

Possible Fujitsu Ducted AC Problems and Fixes

Leaky Ducts

Leaks in the ductwork can cause airflow problems, making it difficult for your Fujitsu air conditioner to cool your home effectively. Depending on the amount of air lost before reaching the vents, you will notice that some rooms are cooler than others, and some are not cooling at all. 

When you have cracks in the ductwork, you will also find an increase in the amounts of dust and pollutants in the air. These particulates sneak into the duct system through the holes and tears, and when air enters your living area, they too enter along with it. 

Contaminants not only lower the quality of air in your home but also create some health problems, especially for people with respiratory allergies. 

So what causes duct leaks, you may ask? 

The most common cause of leaks in the ductwork is broken seals. Ducts consist of many interconnected sections of pipe. If the sealant closing these interconnections is broken, air will be lost. Leaks could also be caused by loose or disconnected ducts, poor mechanical fastening, and sometimes even rodents around or within the ducts. 

How to Fix

The best way to troubleshoot a Fujitsu ducted air conditioner that has leaks in the ductwork is to enlist the services of an HVAC expert. This is especially true if the leak is located in an area that is difficult to reach. A professional will examine the leak with a special camera and suggest ways to access and seal it. 

Blocked/Closed Vents

The cold, conditioned air enters your home through the vents connected to the duct system. If these vents are blocked, your AC will be working so hard to blow air into your living area. And if this problem is not taken care of fast enough, the vents will close entirely, and you will not have any cold air entering your home. 

Not just that, the extra strain put on the AC will start stressing other components like the fan motor, causing them to malfunction, which will significantly reduce the lifespan of the equipment. 

Blocked return vents can cause frosting along with the evaporator coil. You see, this coil needs warm air for the refrigerant inside them to perform its job. If the coil isn’t receiving sufficient air, the refrigerant will get too cold, and ice will build upon it, causing your AC not to work. 

If some parts of your AC have been failing mysteriously or the AC itself seems like it has not been blowing air lately, the problem could be clogged ducts. 

How to Fix

To troubleshoot a Fujitsu air conditioner that has these problems, have an AC tech clean your ducts. Sure, you can open the vents and wipe down the visible area with a wet cloth, but this will likely not help much. Contamination like this goes deeper. Sometimes it will require powerful vacuums and special cleaners to cleanse the ventilation system thoroughly. 

As you wait for the cleaning crew to arrive, though, check to see you don’t have any objects placed in front of the vents, as this could also restrict airflow. You will also want to make sure all vents are fully open. Don’t buy into the belief that keeping some vents closed directs cold air into other rooms and cools them faster; you are just straining your equipment. 

Dirty Air Filters

Okay, problems with dirty filters are not exactly exclusive to ducted air conditioners. After all, dirt, debris, pet dander, hair, and other pollutants can enter any air conditioning unit, regardless of type. 

A dirty filter ranks among the top causes of AC failure. Without regularly cleaning your filter, the filth will prevent hot air from passing through, causing ice to build up around the evaporator coils. As a result, you will have very little or no air coming out of the vents. 

The contaminants can also make their way to the ductwork, fan, and vents, affecting their operations. Like the fan, some components will be forced to work harder to keep your room at your desired temperature, which will cause the unit to start heating up. To avoid fires and damage to the AC, the circuit breaker will trip, shutting the entire system down. 

Usually, Fujitsu ducted systems will shut down if you fail to clean your filter within the instructed time. So, if your aircon is having trouble coming on and you can see ice around the refrigerant line outside, a dirty air filter should be your first suspect. 

How to Fix

Shut off the breaker box and remove the filter. Take it outside and clean the dust off with a garden hose. Let it dry thoroughly before sliding it back into its frame. While you do this, the frost on your evaporator coils should be able to melt completely.

Fujitsu ducted air cons will notify you when your filter needs washing. Ideally, these filters should be cleaned every 14 days. If you ignore the warning, the unit will shut down completely and will not turn on until you have washed the filter. 

Clogged Ductwork

The most common cause of ductwork blockage is dirt, dust, and pieces of old air filters. When these objects collect inside the duct system, they limit airflow, causing your AC to develop problems.

Your Fujitsu ducted air conditioner will not produce cold air if the ductwork is obstructed, and if it does, the air will be stale and moldy due to contamination. In difficult situations, your AC will not even come on. 

How to Fix

If you suspect your ductwork is blocked and you can’t access the clog, contact an HVAC technician right away. They will remove the obstruction and perform a tune-up for the entire ductwork to get your AC up and running again. 

Final Thoughts

The ductwork is a fundamental part of your air conditioning system. However, it will develop cracks and blockages without proper maintenance, limiting the airflow in and out of your AC. 

If your Fujitsu ducted air conditioner isn’t performing its job as it should, check for leaking and clogged ducts, blocked vents, and dirty air filters.

If you’re unable to fix the issue yourself, I recommend calling an experienced HVAC service to fix it for you. You can use the form below to get free AC repair quotes from up to 4 local HVAC experts near you:


  • Chris Hewitt

    Chris is a Texas-based freelance writer who loves the outdoors and working in his garage. When he's not enjoying the Texas sun, he can be found tinkering with all sorts of things in his workshop.

As an Amazon Associate, we earn from qualifying purchases. We may also earn commissions if you purchase products from other retailers after clicking on a link from our site.