A quick service call for a Fujitsu unit that was no longer blowing cold air
At AirGreen , we frequently receive calls from homeowners on the South Shore , particularly in Brossard , regarding problems with Fujitsu wall-mounted heat pumps . These units, renowned for their efficiency and reliability, can nevertheless encounter certain technical issues after several years of intensive use. In this specific case, our client contacted us after noticing that his wall-mounted unit, installed in the main hallway of his residence, was no longer producing cold air despite the fan apparently being in operation.
Diagnosis: a faulty electronic card and a faulty temperature sensor
Upon arrival, our technician performed a complete HVAC system check . The model in question—a Fujitsu 12,000 BTU Halcyon series, running on R-410A refrigerant —was displaying an intermittent error code on the remote control, indicating a communication problem between the main board and the room temperature sensor .
The tests revealed:
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a partially faulty internal control board , causing poor communication signal;
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a damaged temperature sensor (thermistor) , reading inconsistent values;
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a slight accumulation of dust in the evaporator module , reducing airflow.
Intervention: replacement of the card and the sensor, then complete calibration
We immediately started replacing the internal electronic board , a key part that manages communication between the system components. Next, the thermistor sensor was replaced with an original Fujitsu model. Once the parts were installed, we proceeded to:
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a complete electrical test to check continuity and polarity;
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a temperature calibration using a certified infrared thermometer;
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a complete cleaning of the evaporator coil and the interior air filter.
These interventions allowed the system to restart immediately with a constant flow of cold air and a stabilized temperature.
Results: restored performance and comfort regained
At the end of the service, the customer noticed an immediate return of air conditioning to their space. The Fujitsu unit returned to optimal performance : quiet operation, stable room temperature, and reduced power consumption. Our team also checked the outdoor unit to confirm that the compressor was operating at full capacity and that the refrigerant pressure was within factory settings.
We also recommended annual maintenance before each summer, especially for Fujitsu devices located in high humidity areas like Brossard, to extend the life of the electronic boards.
Maintenance Tips for Fujitsu Wall-Mounted Heat Pump Owners
To avoid this type of breakdown in the future, we recommend:
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Clean the interior filters every four to six weeks;
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Avoid turning off the power supply during winter (this prevents the card from remaining in sleep mode);
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Check indicator lights and error codes as soon as unusual behavior occurs;
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Schedule a preventative inspection with AirGreen in early spring.
These simple measures not only help maintain performance, but also avoid costly card replacements.
AirGreen: Precise and Durable HVAC Repairs
Every HVAC repair carried out by AirGreen is based on a rigorous approach, combining advanced electronic diagnostics , original parts and certified labor . Whether you are in Montreal , Laval , Longueuil , on the North Shore or the South Shore , our team is committed to providing fast, transparent and guaranteed service.
In this case, our expertise helped extend the life of the Fujitsu heat pump by several years, while restoring the customer's comfort just in time for the warmer season.
AirGreen — Your HVAC partner in Brossard and throughout Quebec.
Performance, precision and comfort every day.