In many Rosemont–La Petite-Patrie homes, the wall-mounted heat pump (mini-split) has become the simplest solution for air conditioning in the summer and maintaining good comfort during the shoulder seasons. But to remain quiet, efficient, and reliable, it must be properly maintained—not just given a quick filter cleaning.
The photo clearly shows a wall-mounted indoor unit with its front panel removed : the coil (evaporator) is exposed, as well as the electrical components. This is typically the step we take when a customer calls us about reduced performance, an odor at startup, a water leak, or simply for complete preventative maintenance .
In this case, we are dealing with a Lennox wall-mounted heat pump , a residential type, in a very common configuration in Montreal. Since the exact model is not visible in the image, we describe the intervention as consistent with a Lennox MLA series (wall-mounted inverter) , frequently found in comparable installations.
Why this intervention was necessary
A wall-mounted heat pump can continue to blow air while losing a significant portion of its efficiency. The most common signs, especially in urban environments (dust, cooking fumes, fine particles, pet hair), are:
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Reduced airflow (lower ventilation even at maximum setting)
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Less cold air in air conditioning or unstable comfort in heating
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Odors at startup (humidity, biofilm in the bin, damp dust)
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Abnormal condensation or risk of dripping/water leaks
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Noise level increases (clogged fan)
The fact that the unit is open as in the photo indicates a desire to do a real cleaning , with access to the coil, the tank and areas that cannot be cleaned by a simple superficial rinse.
What we do at AirGreen during a complete service on a Lennox wall unit
1) Securing and initial inspection
First and foremost, we ensure the safety of the intervention:
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Power off and basic checks
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Visual inspection of the coil, condensation tray and electrical area
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Checking for traces of moisture, oxidation, and deposits
On a wall, a small anomaly (partially obstructed drain, clogged tray) can quickly result in water damage to the wall.
2) Cleaning of filters and accessible surfaces
Yes, filters matter — but that's just the beginning:
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Cleaning/washing the filters
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Dust removal from accessible grilles and fins
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Checking the shutters and orientation mechanisms
3) Thorough cleaning of the coil (evaporator)
This is the core of air conditioning performance:
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Application of appropriate products (depending on the level of soiling)
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Controlled rinsing to prevent pushing dirt further into the appliance
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Minor reshaping of the fins if necessary (airflow)
A dirty coil = less efficient heat exchange = appliance that works longer for a lower result.
4) Check the tray and drainage (condensate)
The photo shows a section with cables and a conduit/line: during servicing, we ensure that:
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The condensation tray is clean
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The drain line is clear (no mud, no blockage)
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The flow is working properly, without stagnation.
This is the step that most often avoids calls like “it’s leaking from the wall”.
5) Functional and performance checks
Once the reassembly is complete, we validate:
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Blowing temperature and stability
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Mode responsiveness (cool/heat/dry/fan)
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Abnormal noises (vibration, fan rubbing)
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General condition of connections (tighten securely if necessary)
If the behavior suggests a refrigeration issue (rare, but possible), we then recommend a complete diagnosis including checks on the outside.
Unique aspects in Montreal: why maintenance makes all the difference
In areas like Rosemont–La Petite-Patrie, you often find:
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Urban traffic and dust
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Cooking habits are more common in open spaces
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Intensive use during heat waves, then restarted for heating in the autumn
As a result, a wall-mounted unit can become clogged faster than expected, even if the filters are maintained. Regular servicing protects against:
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Air quality
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Energy efficiency
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The lifespan of the equipment
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Peace of mind (fewer breakdowns, less water, fewer odors)
Our AirGreen approach: efficient, clean, and results-oriented
When we service a Lennox wall-mounted heat pump , our goal is simple: to restore stable operation, normal airflow, optimal heat exchange, and eliminate common causes of unpleasant odors and erratic drainage. We prioritize clean, methodical work, with thorough checks before and after service.