A typical service call: loss of performance in a suburban home in Pointe-Claire
At AirGreen , we work daily in the Greater Montreal area to diagnose and repair residential HVAC systems that are showing signs of fatigue. This service call in Pointe-Claire , on Montreal's West Shore , involved a Mitsubishi Electric wall-mounted air conditioner installed in a bright, south-facing living room. The customer had noticed that the unit had stopped cooling effectively for a few days, despite seemingly normal operation.
Diagnosis: an air conditioner that blows, but no longer cools
Upon arrival, the indoor unit appeared clean and functional: no error codes were displayed, the fan was running, but the ambient temperature remained high. This type of symptom is common with refrigerant leaks , dirty coils , or a communication problem between the indoor unit and the outdoor compressor.
After a series of checks—pressures, evaporating and suction temperatures, and wiring continuity testing—our technicians confirmed the cause: a minor refrigerant leak at the flare fitting connecting the wall-mounted unit to the outdoor circuit. This fault is typical of installations that have experienced significant thermal fluctuations over the years.
Intervention: repair, tightening and reloading
We first carried out a controlled tightening of the fitting , followed by a nitrogen leak test to ensure that no further leaks were present. Once the circuit was secured, a complete recharge with R410A refrigerant was carried out in accordance with the manufacturer's specifications, Mitsubishi Electric.
During the same visit, our team took advantage of the intervention to clean the interior and exterior coils , disinfect the condensate tray , and check the proper drainage of the system — maintenance often neglected but essential to the longevity of the device.
Result: comfort restored and performance restored
After restarting, the air conditioner returned to optimal operation. The blowing temperature dropped to 8°C , confirming excellent cooling performance. The customer immediately noticed the difference: the room was comfortable again in less than an hour, without excessive noise or damp smells.
We recommend a complete annual inspection , especially before the warm season, to prevent refrigerant loss and ensure consistent energy efficiency. Simple preventative maintenance can extend the life of a Mitsubishi wall-mounted system by several years.
Why trust AirGreen for your wall-mounted air conditioner repair?
Our RBQ and CMMTQ certified technicians are fully proficient in Mitsubishi Electric systems, renowned for their reliability and installation sensitivity. At AirGreen, we provide:
-
Accurate and rapid diagnostics , without unnecessary replacement of parts;
-
Interventions compliant with Quebec HVAC standards ;
-
Multi-brand expertise covering Mitsubishi, Gree, Fujitsu, Sharp, Midea and many others;
-
Personalized service in all regions: Montreal, Laval, Longueuil, North Shore and South Shore .
Maintenance Tips for Mitsubishi Wall-Mounted Air Conditioner Owners
-
Clean the filters every 4 to 6 weeks during the summer season.
-
Avoid blocking the air outlet with curtains or furniture.
-
Have your outdoor unit inspected before summer for any leaks or obstructions.
-
Request an annual professional service to clean the coils and check the gas pressure.
These simple actions prevent most common breakdowns and optimize energy efficiency.
AirGreen: your HVAC partner in Pointe-Claire and throughout Greater Montreal
This intervention in Pointe-Claire perfectly illustrates our approach: technical rigor, transparency, and respect for performance standards . Whether for an urgent repair , seasonal maintenance , or a complete replacement , we put our expertise at the service of your comfort and peace of mind.