A winter intervention on a snowy roof in Montreal
Montreal winters put a strain on HVAC systems. In the middle of February, our AirGreen team was dispatched to the Côte-des-Neiges–Notre-Dame-de-Grâce neighborhood for a complete breakdown of a Fujitsu wall-mounted heat pump installed on the flat roof of a residential building. The client, a triplex owner, contacted us after noticing that the system was no longer producing heat despite being in heating mode.
When we arrived on site, snow was partially covering the outdoor unit , suggesting defrosting and ventilation problems. The unit, typical of Fujitsu wall-mounted installations, was mounted on a metal bracket to avoid direct contact with the roof, but the freezing temperature and snow accumulation had caused the system to shut down.
Diagnosis and analysis of the problem
Our technicians undertook a complete inspection of the heat pump, focusing on the following:
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Outdoor fan blocked by ice, preventing proper air circulation.
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Defective defrost sensor , which prevented the unit from properly switching to automatic defrost mode.
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Control board showing slight oxidation due to humidity.
All of these elements explained why the system had gone into safety mode , cutting off all heat production to avoid damaging the compressor.
Steps of repair and return to service
After securing the work area and clearing access, we undertook the following operations:
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Complete manual defrosting of the unit using controlled hot air, to avoid thermal shock.
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Replacement of the Fujitsu defrost sensor with a compatible original part.
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Thorough cleaning of the electrical circuit and treatment of the control board with an anti-humidity insulating coating.
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Checking the external fan , lubricating the bearings and readjusting the blade.
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Test the automatic defrost cycle to confirm system stability.
Once this work was completed, the Fujitsu heat pump resumed normal operation, with a blowing temperature in line with the manufacturer's specifications.
Result: comfort restored and prevention of future breakdowns
Thanks to this intervention, the client regained optimal thermal comfort , even in very cold weather. We also took the time to recommend some preventive measures :
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Pre-winter inspection to ensure the probes and defrosting are in good condition.
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Regularly clear snow around the unit to ensure good air circulation.
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Drainage control to prevent ice formation under the condenser.
The owner, relieved to avoid a costly replacement, decided to subscribe to our AirGreen annual maintenance program , guaranteeing seasonal checks and priority service in case of an emergency.
AirGreen expertise: efficiency even in the middle of Montreal's winter
Rooftop work in winter conditions requires technical rigor and increased safety measures . At AirGreen , we have all the necessary equipment to carry out repairs on wall-mounted, central and MultiZone heat pumps , even in the most demanding environments.
Whether in Montreal, Laval, Longueuil, on the North Shore or the South Shore , our technicians intervene quickly to diagnose and repair all brands of HVAC systems : Fujitsu, Gree, Sharp, Midea, Lennox, Bosch , and many others.
A winter breakdown can't wait—but with AirGreen, neither can your comfort.