Rapid intervention on a commercial roof in Lachine
At AirGreen , we are often called upon to work on HVAC systems installed on the roofs of commercial or institutional buildings. Recently, our team traveled to Lachine , in the West Island of Montreal, to repair a Lennox wall-mounted air conditioner whose outdoor compressor was experiencing a performance anomaly.
The context of the intervention
The call came from the manager of a commercial building located in an industrial area of Lachine. The outdoor unit, a wall-mounted Lennox installed on the roof , provided air conditioning for a technical room essential to the site's proper operation. For several days, the on-site team had noticed a loss of cooling power as well as irregular noise coming from the condenser.
Our technician was dispatched quickly to carry out a complete diagnosis on site.
Fault diagnosis
From the initial inspection, several elements were checked:
-
Refrigerant pressures : slightly lower than normal, suggesting a potential leak.
-
Condenser : accumulation of dust and debris reducing heat exchange.
-
Fan : motor functional but blades slightly unbalanced.
-
Control board : intermittent operation when starting the compressor.
Thanks to our measuring instruments and rigorous methodology, we confirmed a micro-leak at the service connection . This had led to a progressive loss of pressure and therefore a reduction in the system's performance.
The steps of repair
-
Complete cleaning of the condenser using a biodegradable product to optimize air circulation.
-
Repair of the leaking connection : re-welding and replacement of the defective seal.
-
Nitrogen leak test to confirm no new leaks.
-
Recharge the system with R-410A refrigerant according to Lennox specifications.
-
Rebalanced the fan to reduce mechanical noise.
-
Checking the start cycle and the electronic card : test successful after recalibration.
Results obtained
Once the repair was completed, the Lennox unit returned to its original performance:
-
Blowing temperature stabilized at 12°C.
-
Standardized power consumption .
-
Operating noise reduced by more than 30%.
The satisfied customer was able to immediately notice the difference in the technical room, where the temperature became stable and constant again.
AirGreen Expertise: The Difference of a Professional Service
This type of intervention clearly illustrates the rigor of our AirGreen team . In a commercial environment, every breakdown can affect productivity or equipment safety. Our certified technicians intervene methodically, without improvisation, and always prioritize the prevention of future breakdowns through:
-
Systematic checks of sealing and wiring .
-
Pressure and performance checks after each repair.
-
Detailed reports sent to the client at the end of the intervention.
We also remind the manager that annual maintenance is essential to maintain the reliability and durability of Lennox systems—particularly when they are exposed on roofs, subject to wind, rain, and the freeze/thaw cycles typical of the Montreal climate.
Best practices to avoid rooftop air conditioning failures
For our business clients in Montreal, Laval, the North Shore and the South Shore , here are some simple but crucial tips:
-
Visually inspect the condensers at each change of season.
-
Clean the coils to prevent overheating.
-
Check electrical connections after winter.
-
Schedule preventative maintenance in the spring before peak season.
An exemplary intervention in Lachine
This project in Lachine demonstrates our expertise in repairing Lennox wall-mounted air conditioners in demanding environments. Thanks to our rapid response, technical rigor, and customer-focused approach, AirGreen remains a trusted partner for all HVAC repair and maintenance needs in the greater Montreal area.