In a single-family home in Sainte-Dorothée, Laval , our AirGreen technicians responded to a call about a Sharp wall-mounted heat pump whose performance had rapidly declined: uneven cooling, a feeling of lukewarm air at times, and longer than usual cycles. The client had also noticed a slight change in noise from the indoor unit—a common sign when the system is working “overloaded” due to a loss of pressure or less efficient air exchange.
On site, the indoor unit was accessible from above, near an open passage (typical configuration of a ground floor with a common area). By opening the casing, the refrigerant connection area was clearly visible on the left side (wall passage of the line set ), as well as the heat exchanger (coil) and the air distribution elements.
Machine type and consistent model
This is a Sharp brand wall-mounted heat pump (mini-split) .
Since the exact model is not legible in the photo, we describe the intervention on a configuration consistent with the Sharp R-32 range , of the Sharp ZU1 type (new generation wall-mounted, very common in residential use).
Observed symptoms: when a mural “seems to work” but no longer follows
In this case, the symptoms were typical of a system that had lost part of its charge or whose circuit was no longer perfectly sealed:
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Inconsistent comfort (temperature that "ceilings")
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Longer operating time
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Reduced efficiency despite normal thermostat demand
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Sometimes, a slight variation in the blowing or expansion noise (without necessarily being dramatic)
These signs can come from several causes, but in practice, leakage at the fitting (flare) or wall passage is among the most frequent — especially if the wall casing has been moved, if the passage hole is tight, or if the fitting has undergone micro-torsion over time.
AirGreen diagnostic: airtightness check and wall penetration inspection
Our diagnosis was carried out in three stages, as is systematically done to avoid "blind" repairs:
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Internal visual inspection
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Opening of the indoor unit
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Checking the drainage, the coil, and the connections
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Control of the line set passage zone (often where the mechanical stresses occur)
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Pressure leak test
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Controlled pressurization (standard verification procedure)
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Observation and control of the fittings: this is precisely the step visible in the photo, with the service tool and the hose (circuit testing)
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Targeted validation
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Confirmation of the faulty area (joint/flare or micro-leak at the point of stress near the wall)
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Verification that the rest of the circuit has no loss
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Diagnostic result: leak located at a connection on the indoor unit side , near the wall passage.
Repair steps: reconnection, securing, and recommissioning
A lasting repair isn't just about "tightening." We've applied a comprehensive method to prevent the problem from recurring:
1) Correctly reattach the flare joint
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Removal/adjustment of the fitting in question
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Reconditioning of the base if necessary (clean surface, correct alignment)
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Correct tightening torque: neither too tight (risk of crushing), nor insufficient (risk of leakage)
2) Stabilization of the wall passage
In many residential installations, leaks are caused by mechanical stress: the line set pushes, rubs, or otherwise flexes at the hole. We have:
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Realigned the path
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Reduces the constraint at the entry point
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A clean finish (cover/sealing of the passage) is recommended/planned to protect the connection in the long term.
3) Validation: pressure, durability, then return to normal conditions
After correction:
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New leak test (stable performance)
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Recommissioning procedure according to manufacturer's best practices
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Verification of operation in heating/cooling mode (as per customer request)
Result: restored comfort, stable performance, and a reassured customer
Once the leak was fixed and the circuit validated, the Sharp wall-mounted heat pump returned to normal operation:
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More stable temperature
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Faster response to demand
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Cleaner and shorter cycles
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Overall impression: quieter and more efficient machine
The customer left with a clear explanation: what caused the performance loss , what was repaired , and simple actions to monitor (warning signs + importance of periodic maintenance).
Why is this type of failure common on a wall-mounted unit?
On a wall-mounted heat pump, the sensitive points are often:
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Flare fittings
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Wall passage (vibration + constraints)
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A coating or finish that allows the copper to "work"
This is exactly why AirGreen favors a comprehensive approach: we correct the leak, but we also correct the mechanical cause that contributed to it.
AirGreen in Laval: Sharp wall repair, accurate diagnosis and sustainable solutions
Whether it is a Sharp (ZU1, ZHU1, TU, THU…) or any other wall-mounted unit, our approach remains the same: rigorous diagnosis, clean repair, complete validation, then recommissioning with measurable results.