When Neglected Maintenance Causes Unexpected Breakdown
At AirGreen , we were recently called to work on a charming duplex in the Ahuntsic-Cartierville neighborhood of Montreal. The owner contacted us after noticing that their Gree wall-mounted air conditioner was no longer cooling properly. Despite the apparent operation of the indoor fan, the unit was no longer producing cool air and was displaying a flashing error code on the control panel.
A typical situation at the beginning of summer, when the wall units have not been maintained for several seasons.
Initial diagnosis: a sensor and filters involved
Upon arrival, our technicians immediately noticed that the front cover of the unit was open , indicating that the customer had attempted to clean the filters themselves. However, there was significant dust accumulation, especially on the evaporator and temperature sensor , causing an incorrect thermal reading.
After a full functional test, we found:
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Low and irregular airflow.
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Dirty interior coils.
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A decalibrated thermistor sensor.
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Intermittent communication between the indoor and outdoor unit.
Repair steps performed by AirGreen
1. Complete inspection and cleaning
We started by completely removing the front panel to access the evaporator. The coils were cleaned with a biodegradable product specific to HVAC systems. This deep cleaning restores thermal conductivity and eliminates odors caused by accumulated bacteria.
2. Checking the thermistor sensor
The temperature sensor (or thermistor ) was dirty and slightly displaced from its housing. We cleaned it and repositioned it correctly, then tested it with a multimeter to confirm its ohm response. After resetting, the error code disappeared.
3. Diagnosis of the external compressor
A communication test with the outdoor unit revealed correct voltage and stable response. No compressor faults were detected. However, we performed a check of the R-32 refrigerant level , which was fully in line with Gree manufacturer's specifications.
4. Reassembly and calibration
After cleaning and testing, we recalibrated the internal settings to optimize temperature control and fan speed.
Result: comfort restored in just a few hours
Once the intervention was completed, the Gree wall-mounted air conditioner resumed normal operation: stable cold air , quiet ventilation , and above all, a balanced indoor temperature . The customer, who was working from home, immediately noticed the difference—comfort restored without excessive noise or fluctuations.
This case demonstrates that a simple lack of maintenance can quickly develop into an apparent breakdown, especially in urban environments like Montreal where fine dust accumulates more quickly on filters.
The importance of annual preventive maintenance
A professional interview allows you to:
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Maintain optimal energy efficiency.
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Prevent electronic failures (cards, sensors, communication).
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Reduce electricity consumption.
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Extend the life of the unit.
At AirGreen, we recommend scheduling an annual inspection in the spring , before the first use of the warm season. This ensures consistent performance throughout the summer and avoids emergencies during heat waves.
AirGreen expertise: rigor, transparency and efficiency
Our technicians work on all major brands of wall-mounted air conditioners: Gree, Sharp, Midea, Fujitsu, Mitsubishi, Bosch, and many others . Each service call is handled according to a specific protocol:
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On-site diagnosis with visual inspection and functional tests.
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Clear and transparent reporting of detected anomalies.
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Immediate repair when parts are available.
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Personalized maintenance recommendations according to the environment (urban, residential, commercial).
This systematic approach allows us to ensure high customer satisfaction rates and reduce unnecessary service callbacks.
Practical tips for owners of wall-mounted air conditioners
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Clean the filters every 4 to 6 weeks .
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Avoid obstructing the air outlet with curtains or frames.
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Check that nothing is blocking the external compressor grille .
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Schedule an annual AirGreen inspection for calibration and gas verification.
These simple actions guarantee lasting comfort and consistent performance, while reducing your electricity bill.
Conclusion
This Gree wall-mounted air conditioner repair in Ahuntsic-Cartierville perfectly illustrates the difference professional intervention can make. In less than two hours, our team diagnosed, repaired, and optimized a system that appeared to be out of service—without replacing any major parts.
AirGreen , your trusted partner in HVAC system repair, maintenance and installation in Montreal, Laval, Longueuil, on the North Shore and the South Shore . Our mission: to restore your comfort, preserve your equipment and ensure peace of mind, summer and winter.