Performance loss detected on a Fujitsu outdoor unit: rapid and lasting intervention by AirGreen
In Sainte-Thérèse , on Montreal's North Shore , a customer contacted us after noticing that his Fujitsu wall-mounted heat pump was no longer adequately cooling his room, despite regular maintenance. The system, installed about five years ago, operated normally until the indoor temperature exceeded 26°C, even when the air conditioning was running at full power.
Context of the installation: a semi-buried space typical of the North Shore
The outdoor unit was installed on a concrete base, leaning against the wall of a pale brick house, near a basement window. This type of installation is common in residential areas of Sainte-Thérèse , where outdoor space is limited.
However, this low-height positioning often exposes Fujitsu units to two problems:
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Moisture buildup around the base and lower coils.
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Invasive vegetation limiting natural ventilation.
Upon arrival, our technician immediately noticed that several plants and weeds were partially blocking the unit's air vents. This situation, although seemingly harmless, creates constant thermal stress on the compressor .
Step 1: visual inspection and initial findings
A preliminary inspection revealed:
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Accumulation of debris on the condenser fins.
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Traces of light oil near the low line connection (sign of microleak).
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Cracked insulation on refrigeration lines.
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No visible electrical anomaly, but a slight abnormal vibration when switched on.
These clues pointed to a progressive loss of refrigerant , accompanied by degraded compressor performance.
Step 2: Complete AirGreen diagnosis
Our standard diagnostic protocol for this type of intervention includes several successive checks:
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Measurement of operating pressures :
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Low pressure: 84 psi (abnormally low)
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High pressure: 280 psi
These values confirm an undercharge of R-410A refrigerant.
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Electronic detector leak test :
A micro-leak was confirmed at the flare connecting the liquid line to the outdoor unit. -
Electrical assessment :
The compressor started correctly, but the inrush current was 15% higher than normal, a result of overload due to loss of efficiency. -
Fan Inspection :
Slight dirt buildup on the blades, but no mechanical imbalance.
Step 3: Repair and Recharge the System
The repair procedure followed RBQ standards and Fujitsu recommendations:
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Complete purge of the circuit and vacuum to 500 microns .
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Replaced the flare fitting and added specialist sealing compound .
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Complete refill of R-410A gas according to the original capacity (1.28 kg).
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Complete cleaning of the exterior condenser fins .
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Renovation of the cold insulation with UV-resistant thermal insulation sheath.
Once the system was restarted, the values stabilized at:
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Low pressure: 120 psi
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High pressure: 390 psi
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Blowing temperature: 18.5°C
Result: restored efficiency and immediate comfort
As soon as the repair was completed, the Fujitsu heat pump returned to full cooling capacity . The customer quickly noticed a drop in ambient temperature and a noticeable improvement in room comfort.
The outdoor unit, now uncluttered and ventilated, operated quietly and without excessive vibration. We also scheduled an annual maintenance follow-up check to prevent any further loss of efficiency.
AirGreen Tips to Extend the Life of an Outdoor Heat Pump
Outdoor installations in backyards or semi-buried areas require extra care. Here are some recommendations we share with each client:
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Remove vegetation around the unit within a radius of at least 60 cm.
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Clean the condenser fins with a mild solution every spring.
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Inspect the insulation of the refrigeration pipes after winter.
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Schedule annual preventive maintenance to check pressures, connections and electronic cards.
Proper maintenance reduces energy consumption and extends compressor life.
The AirGreen approach: expertise, transparency and sustainability
At AirGreen , we view every repair as an opportunity to ensure the long-term reliability of our customers' HVAC systems .
Our team combines precise diagnosis and long-term intervention , while providing advice adapted to the realities of the Quebec climate.
This repair in Sainte-Thérèse perfectly illustrates our commitment: to restore comfort, optimize performance and prevent future breakdowns .
AirGreen — Your HVAC partner in Montreal, Laval, Longueuil, North Shore and South Shore.
Installation, repair and maintenance of residential heat pumps and wall-mounted air conditioners.