In a typical Rosemont–La Petite-Patrie apartment, we were contacted about a WindAir wall-mounted heat pump that was no longer providing the expected comfort. The indoor unit was installed very high on the wall , directly above a passageway (wooden door frames and moldings), a common situation in Montreal apartment buildings where every inch counts. In this type of installation, performance depends on many details: ceiling clearance , condensate drainage quality, the condition of the heat exchanger, and the stability of the ventilation settings.
The situation: decreased performance and daily discomfort
The client described three clear symptoms:
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Uneven cooling (the room remained warm despite a low temperature setting).
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Airflow is less powerful than before.
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Signs of moisture around the unit at certain times (typical when condensate drainage becomes erratic).
This type of complaint is very common on an Inverter wall-mounted heat pump : sometimes it is a simple maintenance that has been postponed, sometimes it is a drainage problem, sometimes it is a load imbalance or a sensor that reads the temperature incorrectly and makes the machine "cycle" at the wrong time.
Our AirGreen assessment: methodical, without assumptions
Upon arrival, our team proceeded as always: visual inspection + functional tests + targeted checks .
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Indoor unit inspection
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Checking the condition of the filters (often clogged, which restricts airflow).
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Checking the heat exchanger (evaporator) : fine dust + oily deposit = reduced heat exchange.
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Check the condensate tray and the slope of the drain (since the unit is near the ceiling and above a passageway, a partially blocked drain can quickly show signs of dampness).
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Functional tests
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Measurement of the temperature difference between the intake air and the exhaust air.
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Observation of the fan's behavior (noise, speed variation, stability).
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Control of control parameters and unit reactions to setpoint changes.
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Checking the flow
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Condensate flow test: slow drainage was confirmed, consistent with the beginning of an obstruction (biofilm + dust), very common in residential environments.
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Diagnostic result: the breakdown was not “mysterious”. We had a combination of causes : reduced airflow due to fouling + slowed drainage, which reduces efficiency and can create episodes of humidity.
The repair: complete, clean and durable restoration
We carried out a complete intervention, because a partial fix often provides comfort that is “better… but not like before”.
1) Technical cleaning of the indoor unit
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Cleaning the filters and inspecting their integrity.
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Controlled cleaning of the evaporator (without damaging the fins).
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Check and clean the turbine (tangential wheel) if necessary, as it is what determines the actual flow rate.
2) Correction of condensate drainage
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Unblocking and rinsing the drain line .
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Cleaning the tank and areas where biofilm forms.
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Validation of the flow under real-world conditions (machine in air conditioning mode, condensate production, stable flow).
3) Stability and performance controls
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Temperature measurements resumed: the differential has stabilized again.
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Cycle verification: better consistency, fewer oscillations.
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Adjusting settings for a Montreal home: ventilation speed, louver orientation and usage recommendations (especially when the unit is installed above a passageway , to avoid "pulling" air directly towards the outlet).
What we can learn from this WindAir case in Rosemont
In a Montreal interior with moldings and tight ceiling clearance, a wall-mounted heat pump can work perfectly… provided that:
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The airflow remains optimal (filters + heat exchanger + turbine).
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The condensate drains freely (clean and clear drain).
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the unit should not be forced to compensate for a mechanical problem with inefficient cycles.
After the intervention, the client found:
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faster cooling ,
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a more stable temperature ,
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quieter and more reassuring operation,
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and above all, the confidence that the WindAir system has restarted on a good footing.
Why AirGreen for wall-mounted heat pump repair in Montreal
At AirGreen, we don't just "get things running again." We aim for real performance : the kind that translates into comfort, stability, fuel efficiency, and peace of mind. Our approach is particularly well-suited to the realities of Greater Montreal: plexes, condos, narrow passages, high-rise installations, drains sensitive to slope variations, urban dust… we know all about it.