A breakdown on a roof in downtown Montreal
One hot and foggy summer morning, our AirGreen team was called for a commercial HVAC service call in the heart of downtown Montreal , in the Ville-Marie sector. The client, an office building manager, reported that several Goodman central heat pump units installed on the roof were intermittently stopping working, causing a loss of air conditioning on several floors.
Occupants complained of hot air in the offices, while some outdoor fans seemed to stop abruptly. On site, the rooftop offered a clear view of the Jacques Cartier Bridge and tall buildings downtown—a typical environment for Goodman's high-capacity systems, designed for centralized commercial air conditioning .
Complete Goodman System Inspection
Our certified technicians began with a comprehensive diagnosis :
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Checking power supplies : Some units had voltage fluctuations.
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Analysis of error codes displayed on control modules: presence of a high pressure (HP) protection code .
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Visual observation : A dirty heat exchanger and fins clogged with urban dust reduced heat dissipation.
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Refrigerant pressure test : slight overpressure observed due to lack of air circulation.
These findings confirmed that the units were entering safety mode due to compressor overheating , caused by insufficient maintenance.
Degreasing, cleaning and rebalancing the system
We immediately began a thorough cleaning of the outdoor coils using a biodegradable product designed for rooftop HVAC systems. This cleaning, combined with a low-pressure rinse , removed the layer of grease and dust that was obstructing the ventilation.
Afterwards :
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We checked the fan motors : two of them showed slow start-up , a sign of weakened capacitors .
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The starting capacitors were replaced immediately.
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A check of the operating pressures confirmed a return to normal parameters (R-410A stabilized at 300 PSI at full charge).
Once operations were completed, each Goodman unit was individually tested for 15 minutes. All returned to stable operation, with a supply air temperature hovering around 11°C , ensuring uniform air conditioning throughout the building.
Recommendations for building managers in Montreal
This case illustrates the importance of regular preventative maintenance on rooftop central heat pump systems, particularly in urban environments. At AirGreen, we recommend:
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Cleaning the coils and filters at least twice a year (spring and fall).
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A complete electrical inspection to prevent motor overheating and failure.
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Checking the refrigerant charge before summer heat peaks.
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The implementation of an annual commercial maintenance plan , which allows problems to be anticipated and the lifespan of equipment to be extended.
Our technicians operate throughout Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore , with maintenance protocols adapted to multi-zone buildings, office towers and urban condominiums.
AirGreen Expertise: Performance, Safety and Reliability
Each AirGreen intervention is carried out with a methodical and professional approach:
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Digital diagnostic equipment for measurement accuracy.
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Safe interventions on flat roofs thanks to anchors that comply with CSA standards.
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Complete documentation given to the manager at the end of the service.
This seemingly simple intervention has a major impact on the energy consumption and sustainability of centralized air conditioning systems. By restoring airflow and stabilizing pressures, we achieved an estimated 12% reduction in electricity consumption in the air-conditioned area.
Final result: comfort restored for the entire building
Thanks to a quick and meticulous intervention, the Goodman central heat pumps in the Ville-Marie building returned to optimal performance. The manager was able to reassure the tenants by the afternoon, and the indoor temperature returned to an ideal comfort level.
At AirGreen , we combine technical know-how , field experience and rapid interventions to ensure the continuous performance of HVAC systems, from the smallest residential dwelling to the largest commercial building in Montreal.