A precision intervention in the heart of downtown Montreal
At AirGreen , we are often called upon to work in downtown buildings where wall-mounted HVAC systems require careful maintenance. This was recently the case in a condo in the Ville-Marie district, where a Midea wall-mounted air conditioner was showing signs of malfunction after several years of continuous use.
Initial diagnosis: intermittent failure and lack of cooling
The customer contacted us after noticing that their wall unit was sometimes blowing lukewarm air despite a properly set thermostat. Upon arrival, our certified technician performed a complete inspection of the Midea indoor system .
The first clues were clear:
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The indoor fan was running intermittently.
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The electronic control module appeared to be damaged.
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The evaporator coil showed significant accumulation of dust and greasy residue , limiting heat transfer.
This combination of factors resulted in a noticeable drop in efficiency and unexpected compressor shutdowns .
Step 1: Safe disassembly and thorough inspection
The unit's housing was carefully removed to access the internal components. As seen in the photo, the evaporator was visibly dirty, which is common in homes where seasonal cleaning has not been performed for several years.
We then have:
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Tested the fan motor using a multimeter.
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Checked the power supply voltage to the control module.
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Inspected the condensate drain , often responsible for safety shutdowns when water stagnates.
Step 2: Complete cleaning and refurbishment of the internal circuit
A complete cleaning of the coil was carried out using a specialized biodegradable product for heat exchangers . This process removes the greasy film and fine dust without damaging the aluminum fins.
The filters were washed and dried, then the condensate tray was disinfected.
We also carried out:
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Disinfection of the tangential fan , often neglected.
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Checking the insulation of electrical connections .
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The ambient temperature sensor test .
Step 3: Electronic Repair
After confirming unstable power supply voltage on the main board , our team replaced the Midea control electronic module , an original part supplied directly by the manufacturer.
Once installed, the new card was reprogrammed with factory settings.
Step 4: Performance Verification and Final Calibration
Before closing the unit, we carried out a series of tests:
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Outlet air temperature : 8°C after 10 minutes of continuous operation.
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Power consumption stabilized at 1.2 A.
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Smooth condensation without drain overflow .
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Correct communication between the indoor unit and the outdoor compressor.
The results confirmed that the air conditioner was now performing like new , with an airflow improvement of more than 25%.
Customer advice: maintenance and prevention
We explained to the client that wall-mounted air conditioners, especially in urban environments like downtown Montreal, require:
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A complete cleaning every 12 to 18 months .
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A drain check before each hot season.
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Maintaining a clear space around the unit to prevent dust from accumulating on the fins.
The client also opted for our AirGreen preventive maintenance program , guaranteeing complete annual monitoring with automatic reminder.
Result: comfort restored and efficiency regained
Thanks to this repair, the customer's Midea wall-mounted air conditioner has regained its original performance. The air circulates efficiently again, noise has decreased, and the indoor temperature remains stable even on the hottest days.
Another concrete example of AirGreen's expertise in the service of comfort and reliability of residential HVAC systems in Montreal and on the South Shore .
In summary: what you need to remember
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Brand : Midea
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Unit Type : Wall-mounted air conditioner (mini-split)
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Location : Ville-Marie (Montreal)
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Problem : Lack of cooling, faulty electronic card, dust accumulation
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Solution : Replacement of the electronic module, complete cleaning, calibration
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Result : Restored performance, optimized airflow, regained comfort
At AirGreen , each intervention is an opportunity to demonstrate our commitment to providing superior quality HVAC service , based on rigor, transparency and lasting customer satisfaction throughout the greater Montreal area.