A mysterious breakdown in a modern residence
At AirGreen , we were recently called to intervene in a contemporary house located in Brossard , on the South Shore of Montreal , for a Fujitsu air conditioning problem . The customer reported that his wall-mounted air conditioner had not blown cold air for a few days, despite a normal display on the remote control. No error code was displayed, but the room temperature no longer dropped, even after several restart attempts.
Upon arriving on site, our technician immediately recognized a Fujitsu mini-split installation , very popular in modern buildings thanks to its high efficiency and quiet operation. The indoor unit, fixed to the living room wall, seemed intact at first glance, but a slight repetitive clicking noise was coming from the motorized shutter.
Diagnosis: Communication interrupted between units
After a series of methodical checks, our team confirmed that the problem came from the communication card between the indoor unit and the outdoor unit . Here are the findings:
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The indoor unit was receiving power, but no control voltage was being transmitted to the outside .
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The communication wires showed signs of oxidation on the terminals.
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The indoor temperature sensor was returning inconsistent values, distorting the electronic reading.
This type of failure is common in homes with high humidity levels or after renovation work where fine dust infiltrates the connections.
Intervention: dismantling, cleaning and targeted replacement
Our technicians carried out a complete and careful repair :
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Power supply cut-off to secure the intervention.
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Partial disassembly of the front panel of the Fujitsu unit to access the control board.
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Thorough cleaning of terminals and connectors with a specialized dielectric product.
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Replacement indoor temperature sensor , genuine Fujitsu part.
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Reconnect the communication cable , followed by a continuity test .
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Power cycle and recalibrate the main board.
During restart, we observed that the outdoor unit resumed its normal cycle after a few seconds — proof that the digital link between the two units was reestablished .
Results: Restored comfort and regained performance
Once the repair was completed, measurements taken confirmed a stable blowing temperature of 12.8°C , in line with the Fujitsu model specifications. The customer immediately noticed that:
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The swing shutter was working silently again .
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The air circulated evenly throughout the room.
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The overall noise level had decreased , a sign of balanced operation.
We also took advantage of the intervention to check the refrigerant charge at the outdoor unit. The pressures were stable, which confirmed that the refrigeration circuit was intact—only the communications board had been affected.
Analysis: The fragility of electronic wall connections
Fujitsu wall-mounted systems, while extremely reliable, have electronic boards that are sensitive to micro-voltage variations and humidity. In modern open-plan homes like the one in Brossard, the proximity of the kitchen or living room can cause steam and greasy dust to accumulate on the internal components.
Our recommendations to avoid this type of breakdown:
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Clean filters every 4 to 6 weeks during the summer.
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Avoid spraying cleaning products near the unit.
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Install a surge protector on the HVAC system supply line.
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Schedule annual preventative maintenance , including voltage and circuit continuity checks.
AirGreen expertise at the service of reliability
Our AirGreen team performs similar interventions every week in the Montreal, Laval, and South Shore regions. Thanks to our extensive experience with Fujitsu systems , we know how to quickly identify the source of the problem and resolve it without unnecessary replacement.
Every service call is an opportunity for us to:
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Extend the life of equipment .
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Optimizing the energy performance of residences.
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And above all, ensuring lasting comfort for our customers, even during the great summer heat.
Conclusion
This Fujitsu wall-mounted air conditioner repair in Brossard perfectly illustrates our expertise in electronic diagnostics and preventative maintenance . By replacing a simple circuit board and reestablishing communication between the units, AirGreen restored this residence's comfort and energy efficiency, while avoiding a costly replacement.
For any repair of Fujitsu wall-mounted air conditioners or any other HVAC system in Montreal, Laval or on the South Shore, our team remains available quickly to offer professional, transparent and lasting service .