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Réparation d’une thermopompe murale Fujitsu à Boisbriand
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Repair of a Fujitsu wall-mounted heat pump in Boisbriand

A service call reveals an electronic card problem

At AirGreen , we know that a high-performance HVAC system relies on a perfect synergy between mechanics and electronics. Recently, in Boisbriand , a customer contacted us after their Fujitsu wall-mounted heat pump suddenly stopped responding to commands. No indicator lights, no audible signals: a complete failure, occurring on a hot spring day.

Our team immediately went on site to carry out a thorough diagnosis .

Initial inspection: a quiet indoor unit and signs of electronic failure

Upon opening the front panel, our technician noticed several typical signs of a PCB problem :

  • No power signal detected on main terminals.

  • The controller's wall display remained off despite the voltage at the circuit breaker.

  • Slight traces of oxidation were visible on the board, particularly near the control connector.

Upon closer inspection, we noticed condensation residue around the temperature sensor and electrical components—a common occurrence when units are not regularly maintained.

Diagnosis confirmed: damaged control board

Through our multimeter analysis and cross-checking of electrical signals, we confirmed that the main control board was no longer responding. A minor power surge, likely caused by a fluctuation in the local power grid, had caused several internal circuits to fail .

For the customer, this meant that the machine could neither start nor receive commands, even though the other components—fan, evaporator, compressor—remained in good condition.

AirGreen intervention: replacement and calibration of the Fujitsu card

Our technician undertook a complete and meticulous intervention :

  1. Safe system logout :
    Before any manipulation, we cut off the general power supply and isolated the circuits to avoid any residual overvoltage.

  2. Removing the defective card :
    The Fujitsu BT416 card was carefully removed, disconnecting each connector identified by color and position, according to the manufacturer's technical diagrams.

  3. Cleaning the electronics compartment :
    We cleaned the internal area with compressed air and applied a protective dielectric coating to limit future moisture.

  4. Installation and calibration of the new card :
    An original Fujitsu card was installed and calibrated according to the customer's specific model parameters. Communication tests between the indoor unit and the outdoor compressor confirmed perfect synchronization .

  5. Reboot and complete system check :
    Once powered up, the heat pump resumed normal operation: the flow of cold air was immediately restored and the indicator lights confirmed stable communication.

Result: comfort restored and reliability increased

In less than two hours, the Fujitsu wall-mounted heat pump was back operating at full capacity. The customer was impressed by the speed and precision of our intervention. We also recommended the addition of a surge protector to prevent future outages due to unstable power.

This type of failure is more common than you might think in residential areas like Boisbriand, Terrebonne and Laval , where voltage fluctuations can affect sensitive electronic components.

The advantages of the AirGreen service

Calling on AirGreen means benefiting from complete expertise in the repair of wall-mounted HVAC systems , regardless of the brand or model. Our technicians:

  • Are trained to quickly diagnose complex electronic faults ;

  • Use only genuine parts that meet Fujitsu standards;

  • Offer fast and guaranteed service , with detailed repair report;

  • Covers all of Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore .

Prevention tips to extend the life of your Fujitsu heat pump

  1. Have your unit inspected once a year to clean the coils and check the integrity of the electrical connections.

  2. Use a surge protector to protect the electronic board.

  3. Clean the interior filters every four to six weeks during the summer season.

  4. Watch for signs of oxidation or excessive condensation inside the unit.

These simple actions help prevent 80% of the breakdowns we see on Fujitsu wall-mounted models.

AirGreen — Experts in repair, maintenance and installation of HVAC systems in Montreal, Laval, Longueuil, on the North Shore and the South Shore.
Fast, precise and long-lasting interventions for optimal comfort in all seasons.