A roof intervention to restore the performance of an HVAC system
At AirGreen , we often work in a variety of settings: single-family homes, condominiums, businesses, and even rooftop installations. This was the case during a service call in Sainte-Julie , on the South Shore of Montreal , where a customer experienced a complete breakdown of his Gree wall-mounted heat pump installed on the roof of his building.
The owner contacted us after noticing that his system had stopped blowing cold air for several days, despite attempts to restart it. This is a critical situation, especially with rising spring temperatures.
Initial diagnosis: a negative pressure system
Upon arrival, our certified technician began with a complete analysis of the refrigeration circuit . Pressure measurements using the dual gauge manifold quickly revealed a lower than normal pressure level , indicating a partial loss of refrigerant.
This type of leak is common in systems exposed to the elements, particularly those installed on flat roofs where frost, heat, and vibration can affect seals and fittings. The compressor would attempt to start, but due to a lack of adequate pressure, it would quickly shut down.
Step 1: Leak Detection and Confirmation
Using an electronic leak detector and a nitrogen pressure test , we located a microleak at a flare fitting connecting the liquid line to the Gree condenser. This type of leak, although minimal, is enough to unbalance the entire system.
So we have:
-
Completely purged the circuit ,
-
Tightened and resealed the connection ,
-
Performed a 250 psi pressure test for 45 minutes to confirm the system was fully functional.
Step 2: Vacuum and recharge with R-32 refrigerant
Once the leak was repaired, we performed a complete vacuum using a professional air evacuation pump , eliminating all traces of moisture and air in the circuit. This process is essential to prevent acid from forming inside the compressor and ensure the longevity of the heat pump.
After stabilizing the vacuum at -30 inHg , the system was recharged with the exact amount of R-32 refrigerant according to the Gree manufacturer's specifications. This step was carried out precisely using a calibrated electronic scale , ensuring a perfect charge in accordance with the technical data sheet.
Step 3: Restart and Performance Check
The unit restart was completed without incident. We observed:
-
Stable pressure during operation,
-
A temperature difference of 10°C between the air drawn in and the air discharged,
-
Power consumption in accordance with Gree standards,
-
And most importantly, no further pressure loss after 30 minutes of continuous operation.
The customer immediately felt the difference: a constant, quiet and stable flow of cold air.
AirGreen expertise: rigor, precision and safety
This type of roof repair requires technical expertise and specialized equipment. At AirGreen, our technicians follow a strict methodology:
-
Systematic control of pressures and leaks ,
-
Use of calibrated measuring tools ,
-
Compliance with environmental protocols related to R-32 refrigerant ,
-
Securing work areas at height in accordance with CNESST standards.
Each intervention concludes with a complete service report , given to the customer, detailing the operations carried out and the values measured. This transparency is an integral part of our commitment to quality.
AirGreen Tips to Avoid Refrigerant Loss
We recommend to all owners of Gree and other brand wall systems:
-
Check exterior fasteners and fittings at least once a year, especially after winter.
-
Have an annual pressure inspection performed by a certified professional.
-
Keep the outdoor unit clear of any obstructions or debris buildup.
-
Watch for signs of underperformance (warm air, frost, unusual noises).
-
Schedule preventative maintenance in the spring with AirGreen to maintain energy efficiency.
Result: restored performance and satisfied customer
Thanks to our intervention, the Gree heat pump in Sainte-Julie is once again operating at full capacity. The customer has regained optimal comfort and stable energy consumption. This repair illustrates the importance of rapid intervention and thorough diagnosis : a single poorly sealed connection can compromise the performance of an entire system.
At AirGreen , we combine experience, state-of-the-art equipment and rigor to provide our customers in Greater Montreal, Laval, Longueuil, the North Shore and the South Shore with reliable, durable service that meets the highest standards in the HVAC industry.