Urgent intervention under a Montreal duplex balcony
At AirGreen , we regularly respond to service calls in the Côte-des-Neiges–Notre-Dame-de-Grâce area, where wall-mounted heat pumps are often installed on metal supports under wooden balconies . This type of configuration, while practical for protecting the unit from the elements, sometimes poses maintenance and ventilation challenges.
Recently, a customer contacted us after noticing that their Gree heat pump system was no longer providing heat, despite the outdoor fan appearing to be running. Upon inspecting the unit, they noticed frost on the condenser surface —a typical sign of a defrost or refrigerant circulation issue.
Diagnosis: Ice buildup and compressor intermittently shutting down
Once on site, our technician performed a complete system diagnosis . The outdoor unit, securely mounted on a galvanized steel wall bracket, showed a partially frosted evaporator coil and traces of oil on the bottom of the coil , suggesting a minor refrigerant leak.
The tests revealed:
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Defrost cycle not completed : the outside temperature sensor was no longer correctly detecting conditions.
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Low pressure in the refrigeration circuit , confirming partial load loss.
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Compressor in thermal overload , stopping regularly to protect itself.
We also noticed that the top plastic shield on the unit was cracked, slightly exposing the control module to humidity variations.
Complete repair: sealing, defrosting and refurbishment
Our interventions were carried out in three specific stages:
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Refrigerant leak repair : After a nitrogen pressure test, we identified the leak at a flare fitting on the liquid side. We reconnected, tightened, and applied a specialized sealant before completely evacuating the system.
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Defrost sensor replacement : a genuine Gree part, calibrated for the model series. This replacement restored reliable automatic defrosting.
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Complete recharge with R-410A refrigerant : with charge adjustment according to the manufacturer's recommended nominal pressures.
We also cleaned the coil using a biodegradable cleaner, removing dust deposits and traces of oil. Finally, the control module was protected by a reinforced cover , designed to withstand the frequent humidity under balcony structures.
Results: Restored performance and increased safety
After restarting, the system displayed:
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Regular and efficient defrosting , even at low temperatures.
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A stable thermal cycle , with a compliant operating pressure.
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Reduced noise level , thanks to the realignment of the wall bracket and the replacement of the anti-vibration silent blocks.
The customer found immediate thermal comfort , and we explained to him how to monitor upcoming defrost cycles to quickly detect any anomalies.
AirGreen Tips: Maintenance of Units Installed Under Balconies
This type of semi-protected installation requires special attention. At AirGreen, we recommend:
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Biannual cleaning of the outdoor coil to prevent efficiency losses.
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A check of the air clearance around the unit — at least 30 cm on each side.
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A visual inspection of the fittings after each winter, to prevent micro-leaks caused by freeze/thaw cycles.
We also advised the customer to have their internal filter checked and to add a light mesh guard above the unit to limit the infiltration of debris from the upper balcony floor.
Local know-how at your service
Every day, our technicians operate throughout Montreal, Laval, Longueuil, the North Shore and the South Shore to ensure the reliability and longevity of your HVAC systems. Whether it's a refrigerant leak , a defrosting problem or an overloaded compressor , we provide a fast, durable solution that complies with Quebec's environmental standards.
At AirGreen, we don't just repair: we optimize the performance of your equipment so it remains efficient and economical, winter and summer.