An intervention on the roofs of Montreal: efficiency and precision signed AirGreen
At AirGreen , we regularly work in demanding urban environments, where restricted access and installation constraints require proven technical expertise. This week, our team was called in to repair a Midea wall-mounted heat pump installed on the rooftop of a residential building in Montreal's Côte-des-Neiges neighborhood.
The customer had noticed a gradual decline in the performance of her system: the unit was no longer cooling properly and an unusual noise was coming from the outdoor compressor.
Diagnosis: A refrigeration connection problem and deferred maintenance
Upon arriving on site, our certified technician first carried out a complete inspection of the outdoor condenser , securely mounted on a metal structure. The first observation: a slight oozing of oil at the refrigerant line connections , a clear sign of a micro-leak of R-32 refrigerant .
The unit, a Midea single-zone 12,000 BTU wall-mounted model, also had dust buildup on the heat exchanger, reducing heat transfer. Internally, the wall-mounted unit's temperature sensor appeared to be corrupted, causing an improper defrost cycle .
We have therefore established a three-step intervention plan:
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Locate and repair the micro-leak at the flare fittings.
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Replace the defective probe with an original Midea part.
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Clean and recalibrate the system to restore its optimal performance.
Repair: precision and safety on the roof
Working on a building roof in Montreal requires strict safety measures. Our technicians first secured the area with harnesses and non-slip supports. Next, the refrigerant connection was disassembled, cleaned, and rebuilt with a new flare and tightening torque calibrated to the manufacturer's specifications.
Once the leak is repaired, we have:
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pulled a full vacuum at -30 inHg for 25 minutes ,
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injected the R-32 refrigerant at the exact nominal charge,
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tested operating pressure (125 psi in cold mode, stable),
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and checked the compressor inrush current , in accordance with the technical data sheet.
The indoor temperature sensor was then replaced, and a full operating cycle confirmed a return to nominal performance.
Result: comfort restored and performance optimized
After our intervention, the customer noticed uniform and quiet cooling from the first minutes. The system returned to optimal energy efficiency, with a delta T of 10°C between intake and exhaust, perfectly within the standards for a Midea device.
We also took the time to remind you of some good preventive maintenance practices :
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cleaning the internal filter every 2 months,
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annual professional inspection,
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checking the tightness of the refrigeration connections,
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clearance from the outdoor unit (minimum 30 cm around).
AirGreen expertise: a complete and rigorous service
Every HVAC repair we carry out, whether in Montreal , Laval , Longueuil , on the North Shore or the South Shore , has the same objective: to ensure the durability, performance and safety of our customers' systems.
We make it a point of honor to:
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diagnose accurately before any intervention,
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use only original parts from manufacturers,
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and provide a detailed report to the customer after each repair.
This approach sets us apart in the residential HVAC market in Montreal and contributes to the lasting satisfaction of our customers.
Conclusion: Another Midea system saved by the AirGreen team
Thanks to a quick and methodical intervention, our client's Midea wall-mounted heat pump in Côte-des-Neiges is now operating at full capacity. This type of service demonstrates our commitment to the quality , transparency , and reliability of our interventions.
For any wall-mounted heat pump , air conditioner , or central HVAC system repair needs, trust the AirGreen team — your trusted partner for lasting comfort, summer and winter.