In the typical duplexes and apartment buildings of the Plateau-Mont-Royal , the wall-mounted heat pump is often installed at the rear, near a window, on a wall bracket attached to the brick—exactly like in the photo: outdoor unit on metal brackets, under the eaves, with insulated refrigerant lines running up to the wall. This type of installation is excellent for saving space… but it requires impeccable mounting and airtight connections, otherwise problems quickly arise.
At AirGreen, we were recently called out for a Fujitsu wall-mounted heat pump (mini-split type, 1 zone), installed on a back balcony, which was no longer delivering the expected performance and was causing daily inconveniences.
Context and observed symptoms
The client contacted us about three very specific symptoms:
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Uneven cooling : air was coming out, but the room was no longer reaching the set temperature.
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Short cycles : frequent starts, rapid stops, the impression that the machine is "straining".
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Noise/vibrations on the structure : on a balcony, a slight vibration can become very noticeable (walls, railings, floors).
In a dense urban environment (trees, dust, pollen, sometimes limited air circulation), these symptoms can come from several causes: reduced heat exchange, obstructed outdoor ventilation, poor drainage, electrical problem… or refrigerant loss .
Our AirGreen diagnostic (on-site method, step by step)
Before touching anything, we always proceed with a structured approach:
1) Visual inspection of the installation
Regarding this installation:
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The Fujitsu outdoor unit is securely mounted on a wall bracket .
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The refrigerant lines are insulated in black sheathing and enter the wall from the rear.
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The unit is under the eaves: good point for protection, but access and dissipation must remain adequate.
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A bracket without damping can transmit vibrations to the brick and structure.
2) Functional checks
We are checking:
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Blowing/suction temperatures (differential),
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Electrical current during operation,
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Cycle stability,
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Condition of the heat exchanger (cleanliness, obstruction, fins).
3) Pressure monitoring and suspected overload
The measurements confirmed “possible” but not optimal operation, typical of a refrigerant charge that is no longer exactly at specification.
At this stage, the priority becomes: to validate the circuit's watertightness .
4) Targeted leak test on the fittings
On mini-split systems, the most frequent cause of insufficient refrigerant charge is a micro-leak at the flare fitting , especially if:
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the tightening torque was not perfect,
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The cut/flare was slightly imperfect,
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the installation is subject to vibrations or seasonal movements.
We therefore carried out a methodical check (detection + pressure test according to good practices), and the leak was located on a fitting of the refrigeration line.
Repair carried out on site
Once the cause was confirmed, we carried out a complete, durable, and compliant repair.
1) Repair of the faulty connection
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Removal and inspection of the scope,
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Resuming the flare properly,
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Reassemble with the correct alignment.
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Controlled tightening (not “by hand by feel”).
2) Vacuuming and stabilization
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Rigorous vacuuming
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Vacuum resistance check (key indicator of actual airtightness),
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Preparation for recharging.
3) Precise recharging
Instead of "adding a little more," we restored the system to its original performance level in a measured way , avoiding:
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underloading (poor efficiency, stressed compressor),
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overloading (abnormal pressures, risk of failure).
4) Vibration reduction (balcony specific)
Since the console is fixed to the brick and the balcony can amplify the frequencies, we also have:
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tightened and stabilized the fixing points,
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Added/optimized damping in the necessary areas.
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checked that the connections (pipes/sheath) do not “pull” on the unit.
Results after intervention
After repair and recommissioning, the customer immediately noticed:
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Return of stable and faster cooling ,
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Longer and more normal cycles (fewer unnecessary starts),
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Significant reduction in vibrations and structural noise ,
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And above all: a renewed confidence in the reliability of the heat pump.
That's exactly the goal of a good repair: not just "that it works again", but that it works as it should .
What we recommend to prevent it from happening again
For a Fujitsu wall-mounted heat pump installed on a wall bracket in an urban environment, here are the best practices:
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Clean/have the indoor unit cleaned regularly (filters + heat exchanger if necessary).
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Keep the outdoor unit clear of debris (leaves, dust, pollen).
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Watch for subtle signs: declining performance, short cycles, new noise,
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Have the fittings and mechanical stability checked after major seasonal variations (freeze/thaw).
Why AirGreen for Fujitsu repairs in Montreal?
A successful HVAC repair is not a matter of "luck." It is:
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a diagnosis that doesn't jump to conclusions
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suitable tools (sealing, vacuum, measurements)
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a complete intervention (performance + reliability + sound comfort)
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and an understanding of local realities: balconies, plexes, wall brackets, restricted access.
At AirGreen, we work precisely with this level of requirement — because a well-repaired system means fewer service calls, more comfort, and a longer lifespan.