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

Mysterious backyard outage turned into engineering success

A homeowner in Sainte-Julie , on the South Shore of Montreal, contacted us about a complete breakdown of his Fujitsu wall-mounted heat pump . The outdoor unit, installed for several years near the back wall of the house, was no longer responding, leaving the residence without air conditioning during the heatwave.

At first glance, the machine simply appeared to be aging, but our experience has taught us that a thorough analysis often reveals unsuspected causes.

Diagnosis: electrical failure and structural deterioration

Upon arriving on site, our AirGreen technician immediately noticed several problematic elements:

  • The outdoor unit was partly obstructed by a homemade wooden structure , used to support climbing plants.

  • The wall facade showed signs of infiltration and deformation , probably caused by poor insulation around the cable passage.

  • The exterior electrical wiring showed signs of moisture and oxidation—a potential medium-term hazard.

After unplugging and testing the system, we confirmed that the outdoor control board was damaged due to a moisture-induced short circuit. The compressor was intact, but communication with the indoor unit had been interrupted.

AirGreen intervention: complete restoration and prevention

Step 1 — Securing and Dismantling

Before any manipulation, we switched off the system and secured the work area, including the wooden stakes and exposed cables.
We then disassembled the electronic board and carried out a continuity diagnosis on the circuits to identify the damaged tracks.

Step 2 — Repair and Replacement

  • Replacement of the Fujitsu control board with an original part, suitable for the existing model.

  • Reconnection of power and communication cables , with reinforced insulation to prevent further infiltration.

  • Application of a heat-resistant exterior sealant around wall passages.

Step 3 — Verification and Calibration

  • Complete test of compressor, fan and temperature sensors .

  • Checking the inrush current and supply voltage .

  • Calibration of communication between units to ensure synchronization.

Once the repair was complete, the system restarted normally. The heat pump resumed its cooling function, with powerful and quiet blowing —proof that optimal performance had been restored.

Results: restored comfort and increased safety

Thanks to this intervention:

  • The power failure has been eliminated at the source .

  • The installation has been regulated and secured .

  • The owner found stable comfort in his house despite the high temperatures.

We also took the time to recommend annual preventative maintenance to the customer, including checking the wiring, condensation drain and cleaning the outdoor coils.

An example of AirGreen know-how on the South Shore

At AirGreen , every situation is unique. Our interventions are never limited to “fixing the problem”: we understand, analyze, and improve the entire system to ensure maximum sustainability.

In Sainte-Julie, as elsewhere on the South Shore , our reputation is based on:

  • Accurate diagnostics thanks to professional measuring instruments;

  • Exclusive use of original parts from Fujitsu, Midea, Lennox, Gree, and other major brands;

  • A human and transparent approach: the customer always understands what is being done and why.

Conclusion

This Fujitsu heat pump repair in Sainte-Julie perfectly illustrates the importance of regular maintenance and a moisture-proof installation.
By restoring the system, we not only restored customer comfort, but also prevented a more serious failure that might have required complete replacement of the unit.

AirGreen – Your trusted HVAC partner in Montreal, Laval, Longueuil, on the North Shore and the South Shore.