A dirty air conditioner causing a loss of performance
At AirGreen , we were called to intervene in an apartment in the Côte-des-Neiges–Notre-Dame-de-Grâce sector of Montreal, for a problem with insufficient air conditioning on a Fujitsu wall-mounted air conditioner . The customer had been noticing a decrease in airflow and a lukewarm air temperature for several weeks, despite the unit appearing to be functional.
This type of situation is common in early summer when units have not been cleaned or maintained for several seasons . Our mission: to restore unit performance without costly replacement.
On-site diagnosis: a completely clogged filter
Initial inspection
Upon opening the front hood, our technicians immediately noticed that the air filters were saturated with dust and fine debris . This dense deposit blocked airflow, forcing the compressor to run longer at lower efficiency.
In addition to the buildup on the filters, we also noticed a film of dirt on the evaporator , which can impair heat exchange and cause ice to form on the coil .
Possible causes
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Maintenance not carried out for over a year.
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Prolonged use in “Auto” mode without regular cleaning.
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Dusty environment (ground floor apartment near a busy street).
Steps for repair and complete cleaning
1. Disassembly and cleaning of filters
The washable mesh filters were carefully removed and cleaned with warm water and mild soap , before being rinsed and dried. We took advantage of the disassembly to check the condition of the motorized shutters and the insufflation turbine , which often become clogged when maintenance is neglected.
2. Cleaning the evaporator and condensate tray
We used a specialized biodegradable HVAC cleaner , applied at low pressure to dissolve greasy and dusty deposits on the evaporator fins.
The condensate tray has been emptied and disinfected to prevent any proliferation of mold or unpleasant odors during operation.
3. Checking the condensate drain
The drain pipe was purged to ensure free flow, eliminating the risk of water backup or internal dripping . This test was crucial, as a partially blocked drain could have caused water damage.
4. Pressure Check and Performance Test
Once the cleaning was complete, we restarted the system to measure the temperature difference between the intake air and the exhaust air . The result: an improvement of more than 7°C , indicating a return to optimal performance.
The refrigerant level was also checked, no leaks were detected.
Result: restored comfort and reduced consumption
After our intervention, the Fujitsu wall-mounted air conditioner regained its full cooling power , while operating more quietly . The customer immediately felt the difference: fresher air, stronger airflow and a neutral odor.
We explained to him the importance of regular preventative maintenance , including:
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Clean the filters every 4 to 6 weeks during use.
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Have the unit checked by an AirGreen certified technician once a year.
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Maintain clearance around the indoor and outdoor unit to prevent accumulation of dust and leaves.
These simple actions extend the life of the device and avoid costly repairs.
AirGreen: your HVAC expert in Montreal and the South Shore
Whether it is for a wall-mounted air conditioner repair , a heat pump installation or complete HVAC system maintenance , AirGreen is recognized for its professionalism, speed of intervention and the quality of its finishes .
Our technicians serve Montreal, Laval, Longueuil, the North Shore and the South Shore , and work on all major brands: Fujitsu, Midea, Gree, Sharp, Lennox, Bosch, Trane, Goodman , and many others.
Conclusion: a simple negligence that could have cost dearly
This case demonstrates how essential annual wall-mounted air conditioner maintenance is. A clogged filter not only causes discomfort—it increases power consumption, prematurely wears out components, and can cause serious breakdowns .
Thanks to our rapid and methodical intervention, the Côte-des-Neiges client regained optimal comfort without replacing the device , and his Fujitsu unit will now operate in ideal conditions for several seasons to come.