A technical intervention in the middle of a Quebec winter
At AirGreen , we often respond to service calls during the cold season, when outdoor heat pumps are under strain. This is exactly what happened in Sainte-Julie , where a customer contacted us after noticing that their COAIRE heat pump was no longer heating adequately despite frequent defrost cycles.
Our team quickly arrived on site, equipped to diagnose and repair any residential HVAC system , regardless of brand or weather condition.
Diagnosis: loss of efficiency and suspected refrigerant leak
Upon our arrival, we noticed that the outdoor unit—a COAIRE wall-mounted heat pump —was operating, but without reaching normal operating pressure. The diagnostic manifold connected to the service valves confirmed our suspicions: the refrigeration circuit pressure was abnormally low.
The customer had also noticed a thin layer of persistent frost on the lines, a typical sign of a lack of refrigerant . Before any recharge, our technician proceeded to:
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A complete check of the circuit's tightness using an electronic detector.
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A visual inspection of the braze joints and flare fittings .
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Monitoring the status of the compressor and fan .
The leak was eventually located on a slightly cracked connection on the discharge side, probably caused by successive thermal expansion cycles.
System repair and upgrade
To ensure a lasting intervention, we have:
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Replaced the faulty fitting and redid the silver solder.
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Pulled a complete vacuum on the circuit to remove all traces of moisture and air.
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Performed an accurate recharge with R410A , using a recovery bottle and a certified analog manifold .
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Checked operating pressures and discharge temperature after return to service.
The system was then tested under different load conditions to confirm its optimal performance.
Result: efficiency restored and customer reassured
Once the repair was complete, the COAIRE heat pump returned to full performance, providing stable and consistent heat throughout the home. The customer, impressed by our prompt response and technical rigor , decided to enroll his unit in our AirGreen preventative maintenance program —an essential measure to avoid future problems related to leaks or clogging.
What we learned from this repair in Sainte-Julie
This intervention clearly illustrates the challenges associated with maintaining heat pumps in winter :
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The cold increases the mechanical stress on joints and brazing.
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Defrost cycles can temporarily mask a lack of refrigerant .
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An accurate diagnosis always requires professional tools (manifold, vacuum pump, leak detector).
At AirGreen, we train our technicians to recognize these warning signs and intervene quickly to extend the life of every HVAC system, regardless of the brand—COAIRE, Fujitsu, Gree, Midea, Sharp, or others.
The importance of regular maintenance
We recommend to all owners of wall-mounted heat pumps :
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Have the system pressure and performance checked annually .
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Ensure complete clearance around the outdoor compressor , especially in winter.
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Never attempt to recharge without the proper equipment: overfilling or improper bleeding can damage the compressor.
With preventative maintenance, your system stays efficient, reduces your energy consumption, and provides consistent comfort year-round.
Why choose AirGreen for your heat pump repairs?
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Rapid interventions in Montreal, Laval, Longueuil, North Shore and South Shore.
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Certified technicians specializing in all residential HVAC systems.
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Honest and transparent service , with full explanation of the diagnosis.
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Warranty on repairs and local after-sales service.
No matter the make or model, you can count on us to refurbish your system and optimize its energy efficiency .