R-410A refrigerant recharge and flat roof diagnosis in Montreal
When a wall-mounted heat pump shows signs of weakness, the cause is often invisible to the naked eye: a refrigerant leak . At AirGreen , we regularly intervene to diagnose and correct this type of problem, which can quickly affect the performance and durability of the system.
This specific case, which occurred in a building in Côte-des-Neiges–Notre-Dame-de-Grâce , perfectly illustrates the rigor of our interventions on the ground.
Context of the service call
The client, a rental property owner, contacted us after his tenant reported a noticeable drop in heating performance in early summer. The outdoor unit, installed on the building's flat roof, was a recent Haier wall-mounted heat pump using R-410A refrigerant .
Our technician has scheduled an on-site visit to carry out a complete check of the refrigeration circuit .
Inspection and technical diagnosis
Upon arrival on the roof, several signs indicated a partial loss of load :
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Suction pressures below normal values.
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Indoor blowing temperature higher than expected.
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Oily traces around a condenser connection, typical of a microleak .
Using a set of digital pressure gauges and an electronic leak detector, we located the problem area. The cause was slight porosity at a pipe crimp .
Steps of repair
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Recover remaining refrigerant using an approved recovery cylinder.
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Re-welding of the defective connection with a blowtorch, followed by a nitrogen pressure test to check the seal.
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Complete vacuuming of the system to eliminate all traces of moisture.
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Exact R-410A recharge , according to Haier manufacturer specifications.
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Check operating pressures and discharge/suction temperatures.
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Final performance test with measurement of delta T between supply air and ambient air.
The photo above illustrates part of this critical step: the pink bottle of R-410A connected to the pressure gauges, during the controlled charging phase.
Results after intervention
After the repair, the heat pump's performance was fully restored :
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Pressures in accordance with Haier values.
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Hot air temperature reaching optimal levels.
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No abnormal noise or vibration.
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Defrost cycle operating normally.
The customer was particularly pleased to see the stability of the system after recharging, and the care taken in cleaning the workstation on the roof.
AirGreen Recommendations
Our technicians remind us that refrigerant levels should be checked every two years, especially on installations exposed to the elements, such as flat roofs. A small, undetected leak can quickly lead to:
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Compressor overheating ,
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An increase in energy consumption ,
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And eventually, excessive noise or system shutdown .
To avoid these inconveniences, AirGreen offers preventive maintenance contracts including condenser cleaning, pressure monitoring, and complete electrical checks.
AirGreen Expertise and Reliability
Working on a flat roof in the heart of Montreal requires technical mastery and strict compliance with safety standards .
At AirGreen, we combine:
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Modern diagnostic tools,
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Expertise on all brands , including Haier, Midea, Gree, Fujitsu and Mitsubishi,
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And a meticulous approach , which guarantees lasting repairs that meet the manufacturer's requirements.
Thanks to our rapid intervention and expertise, this client's Haier heat pump has regained its full performance, ensuring comfort and reliability — even on an urban roof exposed to all four Quebec seasons.
AirGreen — your HVAC expert in Montreal, Laval, Longueuil, on the North Shore and the South Shore.