An urgent service call for a broken wall-mounted air conditioner
On a particularly hot afternoon in Saint-Laurent , a customer contacted us urgently: their Midea wall-mounted air conditioner was no longer producing cold air, despite a light display indicating that the unit was on. This type of breakdown is common during periods of heavy use, and at AirGreen, we know how essential it is to quickly restore thermal comfort in a home.
Initial diagnosis: a visibly open device
Upon our arrival, we noticed that the indoor unit of the wall-mounted air conditioner was disassembled , with the cover and control panel partially detached. The customer had attempted to understand the cause of the problem before our arrival—an understandable initiative, but one that carried risks to the safety and integrity of the system.
Our certified technician began by inspecting the electronic module (control board) and the evaporator coil . The latter was clean, which immediately eliminated the possibility of an air blockage caused by dust. However, the error light on the board displayed a sequence of flashes corresponding to a communication fault between the indoor unit and the outdoor compressor .
Steps for in-depth diagnosis
To confirm this lead, we carried out several checks:
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Voltage measurement on the communication terminals: no stable signal.
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Continuity test of the wiring connecting the two units: irregular result.
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Visual inspection of the power connector and terminal blocks : traces of oxidation identified.
The verdict was clear: the three-wire communication cable was damaged . This type of problem often occurs after several years of exposure to moisture or mechanical stress during a previous intervention.
Intervention and repair
We undertook the complete replacement of the communication cable between the two units (indoor and outdoor) using a shielded cable that complies with Midea specifications. This operation required:
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Complete disconnection of the circuit for safety reasons.
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Careful routing of the new cable in the existing conduit.
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A check of the polarity and tightness of the connections to the terminal blocks.
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System reboot and synchronization test between units.
Upon restart, the two units recognized each other immediately. The outdoor compressor started, and within minutes, the blown air was perfectly cold, confirming that electronic communication had been successfully reestablished .
Results and customer satisfaction
The client, delighted to find optimal comfort, highlighted the speed and clarity of our explanations. We took advantage of the visit to:
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Clean the air filter .
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Check the condensate flow and that it drains properly to the outside.
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Test the remote control and reprogram the operating modes.
Thanks to this complete maintenance, the system has regained its original performance and improved temperature stability in the main room.
Technical analysis: what you need to know
Communication failures between units are more common than you might think. They often result from:
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From poor electrical contact .
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From deterioration of the wiring due to humidity or improper installation.
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From a faulty electronic card , although this is rarer.
An accurate and methodical diagnosis, such as that carried out by our AirGreen technicians, helps avoid costly and unnecessary replacements.
Maintenance tips to prevent this type of breakdown
At AirGreen, we recommend that all owners of Midea and other brand wall-mounted air conditioners :
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Schedule annual preventive maintenance , especially before the hot season.
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Never disassemble the indoor unit yourself , as this may damage the connectors.
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Check drains and filters regularly to ensure optimal air circulation.
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Protect outdoor cables from rodents and moisture.
These simple actions extend the life of your appliance and maintain its maximum energy efficiency.
AirGreen expertise at your service in Saint-Laurent and throughout Greater Montreal
This service call in Saint-Laurent exemplifies our commitment to providing fast, reliable, and professional HVAC repairs . Whether you're in Montreal, Laval, Longueuil, the North Shore, or the South Shore , our teams are ready to work on all Midea heat pump and wall-mounted air conditioner models, as well as other major brands like Fujitsu, Gree, LG, and Sharp.
Our goal: to restore your comfort with transparency, precision and efficiency .
AirGreen – Your reference for HVAC system repair in Montreal and its surrounding areas.