A service call on a typical Montreal flat roof
At AirGreen , we often receive service calls in apartment buildings in the Rosemont–La Petite-Patrie neighborhood of Montreal, where many outdoor wall-mounted heat pump units are installed on flat roofs . This configuration, common in Montreal plexes, presents specific challenges: exposure to the elements, intense heat in summer, snow in winter, and sometimes limited access.
One of our recent calls involved a Samsung Smart Inverter wall-mounted heat pump installed on the roof of a duplex. The customer contacted us after noticing a decrease in performance in cooling mode , accompanied by an irregular noise when the compressor started.
Diagnosis: Reduced performance and unusual vibration
Upon arrival, we performed a thorough inspection of the outdoor compressor . The unit was mounted on wooden blocks attached to an insulating slab—a common installation, but one that can become unstable over time. The fan was running, but the compressor only started intermittently , which explained the insufficient temperature inside.
Our technicians carried out several checks:
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Refrigerant pressures : abnormal, indicating a possible leak.
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Voltage and electrical connections : correct.
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Mounting bracket : slightly misaligned, causing amplified vibration on startup.
After a leak test with an electronic detector, we located a micro-leak on a flare connection connecting the compressor to the refrigeration circuit.
Intervention: repair and complete return to service
We have :
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Degassed the system in accordance with environmental standards.
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Rebuild the flare joint by replacing the nut and applying a specific lubricant to improve the seal.
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Performed a complete vacuum to remove all moisture.
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Recharged the system with R-410A refrigerant at the optimal pressure.
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Re-adjusted the outdoor unit mount with anti-vibration pads to reduce noise pollution.
Once the repair was completed, the heat pump returned to smooth and quiet operation . Pressures were stable, the blown air temperature met Samsung specifications, and the vibration was eliminated.
Expertise tailored to Montreal roof installations
This type of intervention perfectly illustrates the importance of regular maintenance for units installed on flat roofs:
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Direct exposure to sunlight and temperature variations can accelerate the aging of seals and fittings .
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Compressor vibrations are more easily transmitted to the support, which in the long term affects the stability of the installation .
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Freeze/thaw cycles can weaken refrigeration connections .
At AirGreen , we recommend a complete annual check-up before the summer season to prevent this type of breakdown.
Result: comfort restored and durability assured
After our intervention, the customer immediately noticed a return to full air conditioning capacity . We also took advantage of the visit to clean the outdoor coil and check the control board . No other anomalies were detected.
This repair demonstrates our commitment to providing high-quality HVAC service throughout the Greater Montreal area, including Laval , Longueuil , the North Shore and the South Shore . Thanks to our expertise, even installations in complex urban environments—like those on Montreal rooftops—benefit from optimal and long-lasting maintenance.
Best Practices for Outdoor Unit Owners
To extend the useful life of your heat pump:
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Avoid accumulation of debris around the unit.
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Visually inspect supports after heavy rain or frost.
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Schedule annual preventative maintenance with a certified technician.
At AirGreen, we are committed to keeping your HVAC systems efficient, quiet, and energy-efficient, regardless of installation conditions.