An urgent service call in an underground garage
At AirGreen , our HVAC technicians work in all situations—even the most unusual. This week, our team was called out for a service call in an underground garage in downtown Montreal (Ville-Marie district) , where a Slimair heat pump was showing signs of failure. The unit, installed high on a concrete wall, provided air conditioning and heating to a technical area of a recent residential building.
Diagnosis: overheating and safety shutdown
Upon our arrival, we noticed that the Slimair JW outdoor unit, installed in a confined and poorly ventilated space, was showing abnormal heat accumulation . The customer reported that the heat pump stopped after a few minutes of operation, without producing either cold or heat.
After a complete analysis of the refrigeration circuit and the electrical system , we noted several worrying elements:
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Insufficient airflow due to condenser fouling.
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Excessive ambient temperature in the room (lack of ventilation).
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A faulty pressure sensor that caused the compressor to shut down safely.
Repair and maintenance steps
Our technicians carried out a three-step intervention:
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Thorough cleaning of the condenser :
We removed the dust and debris accumulated on the fins to restore optimal airflow . -
Wiring Check and Pressure Sensor Replacement :
A new certified Slimair probe has been installed to ensure the stability of the refrigeration circuit reading . -
Additional ventilation recommendation :
Given the closed configuration of the garage, we recommended adding a small air extractor to limit ambient temperature increases that could further damage the system.
Result: restored performance and enhanced safety
After restarting, the Slimair heat pump returned to its nominal efficiency . The customer immediately noticed temperature stability and a reduction in operating noise . We also tested the system under different loads to verify the efficiency of the compressor and fan.
Our team concluded the intervention by leaving a complete maintenance report , including measured pressures, discharge temperature, and before/after photos of the cleaning.
Maintenance tips for indoor installations
Installations in garages or technical rooms require special attention:
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Check the cleanliness of the condenser regularly.
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Maintain sufficient ventilation around the unit.
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Schedule biannual maintenance before each extreme season (summer/winter).
Regular maintenance prevents unscheduled shutdowns, extends equipment life and optimizes energy consumption .
At AirGreen , we work on all brands of heat pumps, whether Slimair, Midea, Gree, Fujitsu, or Zephyr , throughout Greater Montreal, Laval, Longueuil, the North Shore and the South Shore . Each service call is handled with rigor, transparency and a constant concern for reliability.