A heat pump failure in the middle of a storm: a typical Montreal emergency
At AirGreen , we know that HVAC systems never choose the right time to break down. This service call in Rosemont–La Petite-Patrie , which occurred in the middle of a snowstorm, is perfect proof. Our client, the owner of a recently renovated duplex, contacted us after noticing that his Gree wall-mounted heat pump was no longer producing heat, leaving his home quickly cooling down despite the space heaters.
The context: a harsh climate, a unit put to the test
On the day of the intervention, the outside temperature was hovering around -15°C with strong gusts. The outdoor unit, mounted high on the rear facade of the building, was covered in a thick layer of snow and ice . Despite the robustness of the Gree heat pumps, this accumulation prevented the system from functioning properly and caused a persistent defrost error .
Our team, equipped to work at height and in winter conditions, installed a secure double ladder to access the device.
Step 1 – Complete Inspection and Diagnosis
Before any manipulation, we checked the following critical points:
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R-32 refrigerant pressure using a digital pressure gauge;
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Outdoor coil temperature sensors ;
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Defrost relay on the electronic board;
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Condensate drainage , often blocked by frost.
The diagnosis was clear: the defrost cycle was no longer activating correctly because of a faulty temperature sensor , unable to detect the formation of frost on the evaporator.
Step 2 – Sensor Replacement and Complete Defrost
Once the fault has been identified, our technician has:
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Turn off the power supply to work safely.
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Defrost the unit manually using warm air, not water, to avoid rapid re-freezing.
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Replaced the defrost sensor with a genuine Gree part compatible with the Lomo+ series.
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Cleaned the condenser fins to restore optimal airflow.
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Checked the electrical connections and reset the system.
Once the system was restarted, the heat pump resumed its automatic defrost cycle without interruption and began blowing steady warm air after less than five minutes.
Step 3 – Adjustment and winter maintenance tips
To ensure system durability, we also slightly realigned the wall mount , which was leaning forward, promoting snow accumulation under the compressor base. This type of simple correction extends motor life and improves frost drainage.
Before leaving, our technician explained to the customer how to:
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Visually check the unit for frost after heavy snowfall;
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Clear the bottom and sides of the appliance to ensure good air circulation;
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Never use hot water to manually defrost a heat pump;
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Schedule an annual AirGreen pre-winter inspection to avoid critical breakdowns.
Comfort restored, even in the middle of winter
A few hours after our intervention, the customer confirmed that the indoor temperature had returned to a stable and silent 22°C . Thanks to our quick intervention, he was able to avoid a costly replacement and extend the life of his heat pump.
AirGreen: local HVAC expertise serving sustainable comfort
Whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore, our teams operate even in the most extreme conditions . Each repair is carried out according to the manufacturer's standards and with original parts, guaranteeing optimal performance and total peace of mind.
At AirGreen, we view every emergency call as an opportunity to demonstrate our technical rigor and commitment to the comfort of our customers , whatever the conditions.