When Snow Gets on the Roof: A Typical Montreal Service Call
At AirGreen , we often deal with situations where the weather puts HVAC systems under strain. This service call, which occurred in the middle of winter in Côte-des-Neiges , is a perfect example. The customer contacted us after noticing that their Slimair heat pump was no longer producing enough heat and that the outdoor unit seemed permanently iced over.
Installed on the flat roof of a residential building, the unit was literally surrounded by compacted snow—a typical environment for Montreal roofs after a storm. This type of situation requires special attention: cold, ice, and poor air circulation can cause numerous performance issues, even breakdowns.
On-site diagnosis: a heat pump suffocated by ice
Upon our arrival, our technicians quickly confirmed that the Slimair heat pump was operating in almost constant defrost mode, a clear sign that the temperature sensor or the automatic defrost cycle was no longer performing its role properly. In addition, the warm air produced inside the home had significantly decreased.
Step 1: Complete visual inspection
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Significant presence of packed snow around the condenser.
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Ice buildup on the suction grille.
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Blocked drainage, preventing defrost water from draining.
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No suspicious noise from the compressor: a good sign.
Step 2: Electrical and electronic check
Our technicians then inspected:
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The electronic control module (PCB) responsible for the defrost cycle.
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Temperature sensors on the evaporator and condenser.
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The power supply and internal connections.
The result: a faulty temperature sensor was preventing the defrost control from functioning normally. Once identified, this sensor was replaced on-site with a compatible part supplied by our AirGreen mobile warehouse.
Intervention: complete defrosting and refurbishment of the drainage
Once the electronic problem was resolved, we proceeded to a complete defrost of the coil and cleaning of the condensation pan . The snow accumulated around the condenser was also removed to allow better ventilation.
Our technicians took advantage of the intervention to:
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Readjust the level of the unit , slightly inclined by the freezing/thawing of the roof.
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Check the compressor inrush current to ensure it was not overheating.
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Clean the exchanger fins using a mild, non-corrosive product.
Results: a heat pump regaining its original efficiency
As soon as it was restarted, the results were immediate:
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The hot air blown inside became constant and powerful again.
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The compressor resumed a normal cycle without defrost lockout.
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The room temperature reached optimal comfort in less than 20 minutes.
The relieved customer found a high-performance, quiet system, perfectly adapted to Montreal's winter conditions.
Prevention: Avoid recurrence during harsh winters
To prevent further breakdown, we recommended:
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Periodic snow removal around the heat pump, especially after heavy snowfall.
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An annual inspection before winter to check the sensors and the electronic board.
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The addition of a lightweight protective canopy over the unit, limiting direct snow without hindering air circulation.
At AirGreen , we always emphasize the importance of regular maintenance: simple preventive monitoring can extend the life of a heat pump by more than 10 years.
AirGreen Expertise: Experience Makes the Difference
Our team operates throughout Greater Montreal , whether in Laval , Longueuil , on the North Shore or the South Shore . Each AirGreen technician is trained to quickly diagnose problems related to Slimair , Gree , Fujitsu , Midea systems and many others.
Our vehicles are equipped with all the parts and tools needed to perform on-site repairs, even in extreme conditions. This expertise and responsiveness are what have made AirGreen 's reputation in the field of heating, ventilation, and air conditioning (HVAC) in Montreal.
Conclusion: an effective and lasting repair
This service call for a Slimair heat pump in Côte-des-Neiges perfectly illustrates the combination of technical rigor and practicality that characterizes our work. Despite the harsh winter conditions, we were able to restore the system to full performance while ensuring the customer's peace of mind.
AirGreen is the benchmark in repair, installation and maintenance of HVAC systems in Montreal, Laval, Longueuil, on the North Shore and the South Shore — summer and winter.