An urgent call in rainy weather
On a rainy afternoon in Lachine , our AirGreen team was contacted to work on a KoolKing wall-mounted heat pump installed on a wooden deck. The customer had been noticing a distinct lack of performance in air conditioning mode for several days, accompanied by an abnormal metallic noise. The outdoor unit, placed against a corrugated metal wall and partially exposed to the elements, was showing signs of premature wear due to a lack of ventilation and maintenance .
Balcony or terrace installations, while practical, require precise positioning and maintenance. Poor air circulation can lead to compressor overheating or moisture buildup, which is particularly problematic during Montreal's humid seasons.
Diagnosis: overheating and corrosion of connections
Upon our arrival, we carried out a complete check of the refrigeration and electrical circuit . Our measurements revealed several anomalies typical of an aging system exposed to humidity:
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Excessive discharge pressure , caused by an obstructed air outlet due to the proximity of the wall;
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Oxidation of electrical connectors at the compressor terminal;
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Clogged internal filters , restricting airflow and increasing the thermal load of the compressor;
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Condensate poorly drained , with slight water infiltration into the drainage tray.
We also noticed that the client sometimes used the deck as storage space, which partially blocked the rear ventilation of the unit — an aggravating factor.
Technical intervention: safely restore performance
1. Cleaning and clearing the outdoor unit
We started by clearing the space around the heat pump and cleaning the condenser fins with a non-corrosive, biodegradable product. The goal: to restore airflow and remove dust and pollen deposits.
2. Electrical repair and sealing of connections
The compressor's terminals were oxidized. We replaced them completely with waterproof terminals with reinforced insulation. Heat-shrink tubing was then installed to prevent any future water infiltration.
3. Checking the refrigeration circuit
After checking the pressures, we identified a partial loss of R410A refrigerant . The leak was coming from a loose flair fitting behind the side cover. We tightened the fitting, performed a nitrogen gas test to verify the leak, and then recharged the heat pump with the exact amount prescribed by KoolKing.
4. Drainage and condensate control
We cleaned the condensate line with a mild solution and checked the drain slope. Stagnant water, a potential source of corrosion and unpleasant odors, was eliminated.
5. Final performance test
Once the system was restarted, we recorded a blown air temperature of 9°C and a pressure difference in line with the manufacturer's standards . The compressor operated quietly, without excessive vibration, and the customer immediately noticed a return to comfort.
Results: a refurbished system and practical advice
After our intervention, the KoolKing heat pump returned to full performance. Energy efficiency stabilized and power consumption decreased, proving that the compressor was no longer overloading. The customer also followed our recommendations to extend the life of his unit:
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Maintain a minimum clearance of 30 cm at the rear and 1 meter at the front of the unit;
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Clean the internal filters every 30 days during the summer;
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Inspect cables and connections after each period of rain or storm;
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Have annual maintenance performed by an AirGreen certified technician .
Why choose AirGreen for your heat pump repairs in Lachine
Our certified technicians travel throughout Montreal, Laval, the North Shore, and the South Shore to diagnose and repair all types of HVAC systems, whether it's a wall-mounted, central, or multi-zone heat pump. Each intervention is carried out according to the most rigorous industry standards , with advanced diagnostic tools and a constant focus on durability.
At AirGreen, we believe that a good repair is more than a fix: it's a commitment to long-term performance and reliability .