A sudden lack of cooling in the heart of Montreal
At AirGreen , we often receive urgent calls during hot days when indoor comfort becomes essential . This was the case of a customer living in Côte-des-Neiges , Montreal, whose Midea wall-mounted air conditioner seemed to be blowing lukewarm air despite apparently working. The indoor unit was no longer producing cold air, and the room temperature was stagnating at 27°C.
Initial inspection: a seemingly clean but ineffective device
Upon arrival, we noticed that the Midea wall-mounted air conditioner was visually well maintained: clean filters, indoor coils without visible obstructions. However, the airflow remained lukewarm and the coil temperature did not drop below 18°C, a sign of a refrigeration problem or a communication fault with the outdoor compressor .
The customer also mentioned an intermittent clicking noise , which pointed us towards a faulty electronic board or thermal sensor issue .
Step 1: Checking the indoor module
We started by opening the front panel to inspect the evaporator sensor (thermistor) and the ambient sensor . The values measured with the multimeter showed inconsistent resistance for the observed ambient temperature.
➡️ Diagnosis: The interior temperature sensor was sending an incorrect reading to the control board, preventing the system from triggering the cooling cycle.
We then checked:
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The interior fan motor (no anomalies detected).
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The condition of the coil : clean, with no traces of frost or apparent leaks.
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Electrical connections : securely fastened and free of oxidation.
Step 2: Checking the outdoor module
Our technician continued the diagnosis outside. The Midea condenser would not start, despite the control signal being sent from the indoor unit. Using a multimeter, we confirmed the presence of voltage at the communication terminal, but no response from the compressor .
Upon careful inspection, we discovered a slightly severed communication wire exiting the protective housing, likely damaged by a small rodent or during equipment relocation. This defect prevented the outdoor unit from receiving the start command.
Step 3: Repair and Calibration
Our technicians have:
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Replaced the indoor temperature sensor with a genuine Midea part.
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Repaired the communication connection between indoor and outdoor units.
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Performed a complete pressure and temperature test to ensure the refrigeration circuit is functioning properly.
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Cleaned the filters and airflow sensor to prevent future malfunctions.
Once the system was restarted, the compressor started immediately, and the blown air reached 9°C at the outlet of the indoor unit . After a complete 20-minute cycle, the ambient room temperature dropped from 27°C to 22°C , confirming the success of the repair.
Result: comfort restored and reliability assured
Thanks to this quick intervention, the Côte-des-Neiges client regained consistent, quiet freshness throughout her apartment. The Midea wall-mounted air conditioner resumed normal operation, with optimal energy efficiency.
We recommended a complete maintenance before each summer season , including:
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Cleaning the indoor and outdoor coil ,
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Disinfection of the condensate tray ,
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Drain and sensor control ,
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And checking the refrigerant charge .
The importance of regular maintenance for Midea wall units
A simple faulty sensor may seem trivial, but it can prevent the entire HVAC system from functioning properly . At AirGreen, we always emphasize the importance of annual maintenance: it helps prevent costly breakdowns , extends the life of the compressor , and reduces energy consumption .
Our teams operate throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore , for all types of installation or repair of wall-mounted air conditioners Midea, Gree, Fujitsu, Sharp, Lennox, Zephyr, and more .
Conclusion
This Midea wall-mounted air conditioner repair in Côte-des-Neiges perfectly illustrates the AirGreen philosophy: accurate diagnosis, rapid response, and total customer satisfaction.
No matter the make or model, we bring your HVAC systems back to life with rigor and expertise .
AirGreen — your reference for residential air conditioning and heating in Greater Montreal.