A service call in the middle of winter: AirGreen to the rescue
In the middle of January, our AirGreen technicians were called to an apartment in Saint-Lambert , on the South Shore of Montreal , for a breakdown of a Gree wall-mounted heat pump . The customer, whose system served as both the main heating and air conditioning system, had noticed that the heat pump was no longer producing heat , despite an outside temperature below -10°C.
The outdoor unit, installed on the balcony, was making an unusual noise and seemed to be in prolonged defrost mode. This type of symptom is common during freezing weather, but in this specific case, the cycle did not return to normal, indicating a defrost problem or a faulty sensor .
Complete on-site diagnosis
Upon our arrival, we carried out a series of checks to identify the cause of the problem:
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Visual inspection of the outdoor condenser : no major ice obstruction, but the ventilation grille was partially frosted .
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Refrigeration pressure test : slightly below normal values, suggesting a lack of refrigerant.
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Coil temperature sensor check : erroneous reading confirmed by multimeter.
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Checked the compressor wiring and relay : no anomalies detected.
The verdict: A faulty defrost sensor combined with a slightly low refrigerant charge , causing a prolonged and ineffective defrost cycle.
System repair and upgrade
Our certified technicians performed the following steps:
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Replacement of the defrost sensor with an original Gree part, ensuring compatibility and measurement accuracy.
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Complete recharge of the R-32 circuit , in accordance with the manufacturer's specifications.
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Thoroughly clean the external battery with hot water under gentle pressure to remove any frost residue.
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Complete operating test on hot and cold cycle to validate pressure stability and sensor response.
After the repair, the heat pump returned to optimal performance , with indoor blowing at 44°C and a stable discharge pressure of 370 psi.
Balcony installation: specific features and precautions
This intervention provided an opportunity to recall the challenges associated with installing heat pumps on apartment balconies :
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Restricted space : Airflow must be unobstructed to avoid air short circuits.
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Winter protection : A minimum clearance of 30 cm at the rear and sides is essential to prevent snow accumulation.
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Vibration and stability : A vibration-damping mount protects the masonry and reduces noise transmitted internally.
Our technicians added an anti-vibration pad under the base and slightly repositioned the unit to improve airflow while maintaining safe passage onto the balcony.
Result: comfort restored and reliability assured
After several hours of observation, the heat pump demonstrated:
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a return to the normal defrost cycle (6 to 8 min) ,
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indoor temperature stability ,
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a reduction in external noise ,
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and higher energy efficiency after load adjustment.
The client, satisfied with the speed and precision of our intervention, also subscribed to our AirGreen preventive maintenance program , guaranteeing a complete inspection every season.
AirGreen expertise: your ally for Quebec winters
At AirGreen , we know that a heat pump breakdown in winter is not just an inconvenience: it is a comfort emergency.
Our technicians respond quickly in Montreal, Laval, Longueuil, on the North Shore and the South Shore , to diagnose, repair and optimize all types of HVAC systems — whether they are Gree, Fujitsu, Midea, Sharp or other wall-mounted heat pumps .
We make it a point of honor to offer:
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lasting repairs ,
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certified original parts ,
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and transparent and professional after-sales service .
Each intervention is carried out according to RBQ and CSA standards , with latest generation diagnostic tools to ensure optimal operation all year round.
AirGreen — your trusted partner for wall-mounted heat pump repair and maintenance in Saint-Lambert and throughout Greater Montreal.