On the South Shore, in Saint-Lambert, we intervened at a residential installation where a Fujitsu heat pump was no longer delivering the expected performance. At first glance, the outdoor unit appeared to be in good condition, installed on a wooden deck, near a patio door and a brick wall. However, in practice, the comfort was compromised: inconsistent heating, shorter cycles, and the impression that the unit was "working hard" without ever stabilizing the temperature.
In this type of situation, our approach at AirGreen is simple: never assume , and methodically check every element — from the power supply to the refrigeration circuit.
System type and intervention context
The photo clearly shows an outdoor wall-mounted heat pump unit (mini-split/wall unit) . The compact size, the absence of ductwork, and the connection configuration (insulated piping + wiring) indicate a classic wall-mounted system, very common in condos and townhouses.
In terms of product range, the design and residential use "Greater Montreal" are well suited to a recent generation Fujitsu wall-mounted heat pump, such as the Fujitsu Orion XLTH (R-32) (a model consistent with our climate and often chosen for its stability in heating in cold weather).
Observable installation details (and what that implies)
Several visible elements of the installation helped us to frame the diagnosis:
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Unit placed on a wooden deck , on feet/bases: good for limiting direct contact with water, but vibrations must be monitored (wood sometimes acts as a resonating chamber).
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Insulated refrigerant lines exiting on the side: insulation is essential, but it must remain intact (UV, friction, crushing).
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Wall-mounted circuit breaker/disconnect box nearby: essential for safety and practical for our tests.
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Gutter downspout and overhang near the unit: an important point in winter (ice, waterfalls, defrost cycles). Protection or a slight adjustment of orientation can prevent many problems in the long term.
In short: a clean installation, but with some typical risks (vibration, defrosting, water leakage) that we always keep in mind.
Symptoms reported by the customer
The client described three very telling signs:
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Uneven heating : some days it was fine; other days the machine struggled.
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Abnormally long temperature rise time .
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More frequent cycles (stops/starts) and more noise outside.
These symptoms can point to several causes: fouling, sensor, fan, power supply… but very often, in residential settings, we end up confirming or ruling out one major hypothesis: a suboptimal refrigerant charge , often due to a micro-leak on the fitting.
Our AirGreen diagnostic (concrete steps)
We proceeded as follows:
1) Electrical and safety checks
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Checking the disconnect switch, connections, and power supply stability.
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Visual inspection of the cables and service inlet on the unit.
Objective: to ensure that the problem is not a voltage drop, a loose connection, or an overheating power component.
2) Mechanical inspection and airflow
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Checking the clearance around the unit (exchanger breathing).
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Leg stability and leveling check.
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Observation of the condition of the grid and the exchanger (fine dirt, pollen, dust).
A partially obstructed heat exchanger can reduce capacity and increase cycling.
3) Refrigeration control and leak detection
Next, we move on to the heart of the system:
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Operating measurements (pressures, temperatures, superheating/subcooling depending on the mode).
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Careful checking of the fittings (often at the level of the flanges ).
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Leak test (professional method) to confirm the hypothesis.
In this specific case, we confirmed a micro-leak at the level of a flare fitting , typically caused by a slight imperfection in bearing, a non-optimal tightening torque at the start, or a mechanical stress on the connection (vibration + thermal expansion).
The repair: what we did, in concrete terms
Once the leak has been identified, you don't "add" gas blindly: you repair it properly and bring the system back to a stable state.
Our steps:
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Securing and recovering/managing the refrigerant according to applicable rules.
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Resumption of the flare connection :
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disassembly,
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Scope inspection,
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reshaping/adjustment if necessary,
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repositioning with the appropriate method and torque.
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Nitrogen pressure test to validate the seal (key step).
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Vacuuming (complete dehydration of the circuit).
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Weight-based charging (the only reliable way to ensure proper charging).
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Restart + complete heating and stabilization tests .
In parallel, we also have:
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Cleaned the critical areas of the heat exchanger,
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Checked the defrosting behavior,
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A slight adjustment to vibration management (pads/anti-vibration if necessary) is recommended given the support on the terrace.
Immediate results and benefits
After the intervention, the improvements were clear:
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Temperature more stable and heating back to normal.
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Longer and more efficient cycles (fewer unnecessary stops/starts).
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Reduced external noise (the machine works less “under stress”).
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Trust restored : the customer now knows that the system is waterproof, properly charged, and ready for winter.
This is exactly the kind of repair that changes everything: a small leak may seem “minor”, but it often leads to decreased performance, overconsumption, premature wear … and a lot of discomfort.
Why entrust a Fujitsu repair to AirGreen
A Fujitsu heat pump (like an Orion XLTH or an equivalent range) is an excellent machine, but its performance depends heavily on details that many people overlook:
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Perfect seal,
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rigorous load,
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Serious vacuum cleaner
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Complete control under real-world conditions,
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respect for clearances and the installation context (terrace, ice, gutters, etc.).
At AirGreen, we treat every call as a precision intervention: diagnosis, proof, correction, validation . No "quick fixes" that come back to haunt the customer two weeks later.