AirGreen intervention on a Montreal roof: efficiency restored for a Midea heat pump
On the flat roofs of Montreal's Rosemont–La Petite-Patrie neighborhood, our AirGreen team recently carried out an intervention on a Midea wall-mounted heat pump installed on a raised aluminum support. The client, a duplex owner, contacted us after noticing a lack of air conditioning power and an unusual noise coming from the outdoor unit.
This type of situation is common during the first warm days of spring in Montreal, when HVAC systems resume service after a long winter.
Diagnosis: mechanical noise and reduced performance
Upon arriving on site, our technician observed a Midea compact condenser positioned on a flat roof, well ventilated, but exposed to direct sunlight.
Visually, there was no sign of leakage or icing, but the fan was running at irregular speed , and the operating pressure was below standard.
Diagnostic steps:
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Electrical check : correct power supply, stable voltage at 240 V.
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Fan motor inspection : The motor bearing showed excessive play, causing a rubbing noise.
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Inverter compressor control : slight delay in startup, but no electrical failure.
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Refrigerant pressure reading : partial deficit of R-410A refrigerant, indicating a slow microleak .
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Inspection of welds and flare fittings : a slight trace of oil spotted near the discharge fitting confirmed the leak.
Repair: precision, cleanliness and reliability AirGreen
Our technicians undertook the complete repair of the unit following the official Midea procedures:
1. Repair the leak
The leak was coming from a poorly sealed flare fitting . We disassembled, cleaned and resealed the seal using a specific HVAC sealing compound , then tightened it with a torque wrench to ensure optimal pressure.
2. Replacing the fan motor
The worn fan motor has been replaced with an original Midea model with sealed ball bearings, ensuring quiet and long-lasting operation, even under extreme temperature variations.
3. Refrigerant recharge and calibration
After a complete vacuum, we recharged the system with the exact amount of R-410A , then checked the operating pressures and compressor discharge temperature.
4. Final performance test
After 20 minutes of operation, thermal efficiency was restored to 100%, with stable pressure and a 60% reduction in noise levels . The air blown inside reached 9°C in air conditioning mode—an excellent result for a system over five years old.
Technical analysis: common causes of roof failures
Rooftop installations, such as the one in Rosemont–La Petite-Patrie, offer optimal ventilation, but also present certain challenges:
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Vibrations amplified by light metal structures.
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Extreme temperature variations (from winter frost to summer heat).
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Expansion of fittings causing micro-leaks of refrigerant.
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Accumulation of dust and pollen on the condenser, especially in spring.
These factors require rigorous annual maintenance , especially for brands like Midea , Gree , Fujitsu or Sharp , which are very present in residential installations in Greater Montreal.
AirGreen Tips to Extend the Life of a Wall-Mounted Heat Pump
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Clean the coils twice a year to maximize heat exchange.
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Have connections and pressures inspected before each air conditioning season.
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Check the noise level : Any change in noise is often the first sign of a mechanical problem.
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Maintain a minimum clearance of 30 cm around the outdoor unit to avoid recirculation of hot air.
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Install anti-vibration mounts for rooftop units to reduce stress on the compressor.
Result: restored comfort and a reassured customer
Once the repair was completed, the owner could immediately see the difference:
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Rapid cooling of its housing.
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Operational silence restored.
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Stabilized energy consumption thanks to improved compressor efficiency.
As always, our technicians left the site clean and secure, with a detailed report of the pressures, temperatures and interventions carried out.
AirGreen: the HVAC reference in Montreal and surrounding areas
Every service call is an opportunity for us to excel and demonstrate our commitment to quality.
Whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore , AirGreen offers repair and maintenance services for Midea, Gree, Fujitsu, Lennox and other brand wall-mounted heat pumps with constant attention to detail and performance.
Our interventions combine technology, expertise and transparency to guarantee the reliability of your HVAC systems, year after year.
AirGreen – Your trusted HVAC expert in Montreal and the greater metropolitan area.
Comfort, efficiency and impeccable service — that's our signature.