Precise diagnosis and complete intervention in a Laval residence
When a customer from Sainte-Dorothée , Laval , contacted us about a Midea MultiZone heat pump problem, the symptoms initially seemed trivial: a drop in performance and less cold air than usual. However, when it comes to HVAC systems , a simple loss of efficiency can mask a more serious problem. Our AirGreen team quickly arrived on site to perform a complete diagnosis and correct the situation before it escalated.
Initial analysis: a loss of refrigerant pressure
Upon our arrival, our technicians noticed that the outdoor unit—a Midea MultiZone heat pump installed on a galvanized steel support—was working, but in an abnormal manner:
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The compressor ran continuously , without a stop cycle.
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The fans appeared to accelerate in spurts , a common sign of pressure instability.
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The refrigerant line temperatures were not within Midea's nominal values.
Using our digital manifold , we quickly confirmed a noticeable drop in pressure in the circuit, indicating an R-410A refrigerant leak .
Step 1: Leak Detection
Our technicians carried out a complete leak test:
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Visual inspection of flare and brazing connections: no visible traces of oil.
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Nitrogen pressure test at 350 psi to verify line integrity.
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Use of an electronic leak detector around service valves and wall connections.
Result: a microleak was located on a solder joint at the condenser outlet , probably due to prolonged vibration combined with mechanical stress on the copper pipe.
Step 2: Repair and repressurize the circuit
The repair procedure was carried out according to AirGreen standards:
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Complete emptying of residual gas in accordance with environmental standards.
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Repair of defective solder with a high-strength silver alloy.
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New nitrogen test for 20 minutes: no pressure loss detected.
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Creation of a high vacuum at -500 microns to eliminate all traces of humidity.
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Accurately recharge the R-410A system according to the factory charge indicated by Midea.
Step 3: Final Checks and Recalibration
After recharging, we proceeded to:
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Verifying subcooling and superheat using the digital manifold.
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Energy efficiency analysis : the delta T measured between the supply and intake air reached 10.4°C — proof of optimal efficiency.
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Testing the interior zones to confirm that each evaporator was operating correctly, with no flow imbalance or noticeable temperature difference.
The Midea compressor returned to stable and quiet operation, and the system began to modulate efficiently according to the needs of the different zones.
Why does this type of failure often occur on MultiZones?
MultiZone heat pumps , although very efficient, present certain vulnerabilities when installed in urban environments:
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Vibrations and thermal expansion of copper pipes causing long-term microleaks.
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Misalignment of wall brackets may put stress on the fittings.
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Load variations between the inner heads, resulting in pressure imbalance.
Our AirGreen technicians are trained to detect these anomalies at the first signs, thus avoiding costly repairs or a complete loss of refrigerant gas.
Result: restored comfort and optimal energy efficiency
Following this intervention, the client was able to regain perfect comfort throughout his home. The various zones were once again cooling efficiently, and electricity consumption decreased by nearly 20% according to the readings from his smart panel.
We also installed additional insulation on the refrigeration lines to reduce heat loss and extend the durability of the system.
AirGreen expertise in Sainte-Dorothée and throughout Laval
Every AirGreen service call is an opportunity to demonstrate our expertise in MultiZone heat pump repair . We operate throughout Laval, Montreal, Longueuil, the North Shore and the South Shore , with the same rigor and attention to detail.
Our advantages:
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Technicians certified and trained in Midea, Gree, Fujitsu, and Daikin protocols.
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Digital diagnostic equipment for maximum accuracy.
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Fast and guaranteed service , even during periods of high demand.
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Original parts and ecological products that meet Quebec standards.
Conclusion: a lasting repair for restored performance
This intervention in Sainte-Dorothée illustrates our commitment: to offer a fast, precise and sustainable service. The Midea heat pump is now operating at its full potential, guaranteeing comfort and energy savings throughout the year.
At AirGreen, we know that the performance of an HVAC system depends as much on the quality of the installation as on the rigor of its maintenance and repair. It's this approach that makes us a trusted partner throughout Greater Montreal.