A delicate intervention on a typical Plateau balcony
In Montreal's bustling Plateau-Mont-Royal neighborhood, HVAC installations often present unique challenges due to older building layouts and limited space. Recently, we at AirGreen were called to repair a Fujitsu wall-mounted air conditioner installed on a small balcony of a red brick duplex.
The customer complained of a lack of cooling power and unusual noise coming from the outdoor unit.
Context: a wall-mounted air conditioner installed on an urban facade
The affected system was a Fujitsu 12,000 BTU wall-mounted air conditioner , installed approximately five years ago. The outdoor unit, securely mounted on a wall bracket, was protected by a decorative wooden lattice fence , typical of Montreal balcony designs.
However, this type of configuration can impair air circulation around the condenser , causing overheating or abnormal pressure in the refrigeration circuit , especially in summer.
During our inspection, we immediately noticed a lack of clearance around the condenser grille. This often overlooked detail can be the cause of many performance issues.
Diagnosis: loss of efficiency and compressor noise
Our technician carried out a complete analysis of the system :
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Measured pressures too high , indicating insufficient heat exchange.
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Condenser fan functional , but accumulation of dust and debris on the surface of the exchanger.
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Slight mechanical noise when starting up, typical of compressor imbalance or lack of refrigerant compensated by overheating .
In order to establish an accurate diagnosis, we used a digital manifold , a probe thermometer and an ammeter to check the power consumption .
The results confirmed an imbalance in the refrigeration system , caused by both an imperfect refrigerant charge and restricted ventilation .
Step 1: Cleaning and Reconditioning the Condenser
Before any recharging, we removed the protective grille and carried out a complete cleaning of the external exchanger :
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Application of a specialized non-corrosive HVAC degreaser .
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Low pressure rinse to remove embedded dirt.
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Air dry before reconnecting power.
This cleaning, although simple, immediately improved the ventilation of the condenser and reduced the noise of the compressor.
Step 2: Check the circuit and recharge with refrigerant
Next, we retrieved the existing charge to measure it accurately . The system contained approximately 40% of the nominal amount of R-410A , which explained the temperature fluctuations observed by the customer.
After a nitrogen leak test to verify the absence of leaks, we carried out a complete vacuum of the circuit, followed by an exact recharge of 1.1 kg of R-410A in accordance with Fujitsu specifications.
The new pressure readings were perfect: high pressure stable, low pressure balanced, and superheat controlled at 9°C .
Step 3: Performance testing and calibration
Once the air conditioner was recharged, we started the performance test :
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Blown air temperature : 7.5°C.
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Room temperature : 24°C.
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ΔT (differential) : 16.5°C, excellent for this type of wall installation.
We also calibrated the indoor unit's airflow to ensure optimal flow, and checked the electronic communication between the modules via the control panel.
Everything worked smoothly and quietly.
Step 4: Tips to improve ventilation and prevent breakdowns
Our technicians recommended that the customer:
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Widen the clearance area around the unit (minimum 30 cm at the rear and sides).
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Clean the outdoor heat exchanger at least once a year .
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Plan to check pressures in the spring before the hot season.
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Avoid decorative obstructions too close to the condenser.
These adjustments ensure extended compressor life and optimized energy consumption .
Result: restored efficiency and comfort regained
Thanks to this meticulous intervention, the Fujitsu wall-mounted air conditioner was restored to its original operation. The customer immediately noticed a reduction in noise , improved cooling power , and consistent thermal stability throughout his home.
This type of intervention, typical of urban environments such as the Plateau-Mont-Royal, clearly illustrates the importance of regular maintenance adapted to each architectural configuration .
AirGreen: your HVAC expert in Montreal and surrounding areas
At AirGreen , we understand the realities of Montreal buildings—whether they are duplexes, condos, or multi-story houses.
Our certified technicians operate in all areas of Montreal, Laval, Longueuil, the North Shore and the South Shore , with cutting-edge diagnostic tools and recognized rigor.
Fujitsu, Midea, Gree, Sharp, Zephyr, Goodman, Lennox, Bosch : no matter the brand, our commitment remains the same— to ensure performance, reliability, and lasting comfort for every customer.