In a Ville-Marie residence, our AirGreen team was called to repair a Fujitsu wall-mounted heat pump installed above a door frame (a common location in condos and apartments where wall space is limited). The client was experiencing a typical problem: water/humidity and inconsistent cooling performance, especially on warmer days.
This is a Fujitsu wall-mounted heat pump (mini-split) from the Halcyon range (the marking is visible on the indoor unit). Since the exact model isn't visible in the photo, we're sticking with this type of installation: a "new generation" Fujitsu wall-mounted unit (Halcyon range / equivalent to Altair) , very common in residential settings in Montreal.
Context: a Fujitsu unit installed above a door (real-world constraints)
An installation above a door can work very well, but it does impose certain requirements:
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Airflow : the air passes through a passage (corridor/door), which can create cooler areas and warmer areas.
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Condensate drainage : the drainage line must maintain a perfect slope; the slightest obstruction can cause overflow and dripping .
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Maintenance access : the location is visually convenient, but more difficult for a complete cleaning of the tank, turbine and drain.
This is exactly what explained the observed symptoms.
Symptoms reported by the customer
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Traces of water / drops under the unit at certain times of the day
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Less consistent cooling , with a feeling of humidity in the room
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A slight hissing noise, more pronounced than usual (often caused by turbine fouling)
Our AirGreen diagnosis (methodical, without assumptions)
On site, we proceeded as we always do on a Fujitsu mural:
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Inspection of the filter and the exchanger : accumulation of fine dust (classic in urban environments and office rooms).
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Condensate tray check : presence of abnormal stagnant water.
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Drainage test : slow flow → almost certain sign of a partially blocked drain .
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Fan (turbine) control : light to moderate fouling, which can impair airflow and promote condensation.
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Validation of general operation (modes, unit response, stability): the unit was functional, but penalized by the deficient maintenance of the condensate circuit and airflow.
The verdict: insufficient drainage + fouling → condensation that does not drain properly, hence the water.
Repair steps completed
1) Complete cleaning of the indoor unit
We disassembled and cleaned the critical components:
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Filters
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Coil/heat exchanger (controlled cleaning, without damaging the fins)
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Condensate tray
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Air intake zone
Objective: to restore normal heat exchange and reduce excess condensation.
2) Unblocking and securing the drainage line
This is the key step in this type of case:
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Clearing the obstruction (residue + moistened dust)
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Rinse and flow test
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Verification that the water drains quickly, without backflow
3) Cleaning the turbine (blower wheel)
When the turbine is dirty, the flow rate drops, moisture remains “stuck”, and the machine may seem less efficient.
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Targeted cleaning
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Vibration/noise check after reassembly
4) Final checks and performance tests
Once everything is back in place:
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Air conditioning test
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Qualitative measurement: more stable airflow, more uniform sensation of cold
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Observation: no leaks , fluid drainage
Result: restored comfort and more stable operation
After the repair:
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No more water under the unit
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More regular air conditioning (less residual humidity)
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Quieter and smoother operation
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Customer reassured: the machine wasn't "broken" in a mechanical sense — it mainly needed a precise diagnosis and repair of the drainage and airflow.
This is exactly the kind of intervention where expertise makes the difference: we don't just do a "quick clean-up", we treat the real cause of the problem.
Why this problem often occurs in Montreal (and how to avoid it)
In a residential context in Greater Montreal, several factors exacerbate this scenario:
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Fine dust (traffic, construction, urban life)
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Prolonged use in air conditioning during the summer
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Filter maintenance forgotten (even 1–2 months may be sufficient)
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A drain that gradually becomes clogged and eventually slows down
Our simple recommendation: regular cleaning of filters + complete periodic preventative maintenance (including drainage and turbine), especially when the unit is placed in a “critical” location such as above a door.