Complex diagnosis for a faulty wall system
At AirGreen , we were called to Sainte-Dorothée (Laval) for an urgent repair of a Gree wall-mounted air conditioner that had not been working for several days. The customer, concerned about the rising temperatures inside his home, had noticed that his wall-mounted unit was no longer responding at all to the remote control commands. At first glance, the display was off and there was no reaction when the power was turned on.
Upon our arrival, our certified technicians conducted a complete inspection of the indoor unit . The front panel had already been removed by another technician, revealing the exposed main circuit board . This situation immediately alerted us, as an exposed circuit board without protection can be prone to damage due to moisture or static surges.
Step 1: Electrical analysis and securing the system
Before any work was carried out, we disconnected the power supply to secure the workstation. Once safety was assured, a voltage test confirmed the presence of a stable 240V voltage coming from the dedicated circuit breaker, which ruled out a main power supply failure.
However, power was not reaching the control board properly. A close inspection revealed a burnt trace on the circuit board , likely caused by a power surge or a poor neutral wire connection .
Step 2: In-depth diagnosis of the electronic card
The main control module showed signs of oxidation around the connectors, indicating possible moisture infiltration . We carefully cleaned the contacts with a dielectric cleaner and performed continuity measurements on the critical components:
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Internal fuse: blown.
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Starting resistance: impaired.
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Microcontroller: not powered.
The diagnosis was clear: the main board was out of service .
Step 3: Repair and Calibration
Rather than replacing the entire system, we opted for a targeted repair to minimize costs for the customer. A new, original Gree motherboard was installed, along with a full calibration of the room temperature sensor and a fan motor test.
We also replaced the internal thermal fuse and tightened all terminal block connections to prevent any future short circuits. Once the system was reassembled and the faceplate reattached, we proceeded to reapply power .
Step 4: Validation of operation
Upon restarting, the Gree wall-mounted air conditioner turned on normally. The LED indicators were stable and the remote control responded perfectly. After 10 minutes of operation, the measured blowing temperature was 8.7°C , confirming optimal performance.
We then checked the condensate drainage as well as the defrost cycle to ensure the long-term reliability of the system.
Step 5: Maintenance and prevention tips
Before concluding the intervention, our team advised the client:
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Have the coils cleaned at the start of each season.
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Avoid exposing the electronic card to the open air.
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Have the supply voltage checked during future preventive maintenance.
We also recommended a complete annual check-up by our AirGreen certified technicians to prevent any future damage.
Result: comfort restored to Sainte-Dorothée
Thanks to our rapid and methodical intervention, the client's Gree wall-mounted system regained its full performance and energy efficiency . This case illustrates the importance of a professional diagnosis before any complete replacement of an HVAC unit.
At AirGreen , we operate throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore , for complex repairs or preventive maintenance, always with the same rigor and passion for a job well done.