In this type of backyard, typical of Montreal—brick wall, small slab, vegetation close to the unit—a heat pump sometimes works harder than it should. This week, we intervened in Rosemont–La Petite-Patrie to restore a Tosot wall-mounted heat pump (outdoor “Inverter” unit) to full working order, whose efficiency had dropped significantly.
The client's objective was simple: to regain stable comfort, without abnormal noise, without short cycles, and above all with air conditioning that finally "pushes" like before.
The context: a Tosot wall-mounted lamp installed on wall brackets, in a confined environment
On site, the Tosot outdoor unit was wall-mounted using brackets (a good practice to limit corrosion and facilitate drainage), but in a fairly "lively" environment: plants, tall grass, nearby objects , and a rather narrow service area. This type of setup may seem insignificant, but it directly influences:
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air circulation around the condenser,
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the accumulation of dust/plant particles on the heat exchanger,
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and accessibility to perform a proper diagnosis (pressure readings, load control, etc.).
Reported symptoms: poor cooling and unstable comfort
The client described to us very typical signs of a system that is no longer properly "calibrated":
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Cooling is less powerful than before (longer temperature drop time)
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Uneven comfort in the rooms (fluctuating temperature)
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Sometimes it feels like the machine is straining or running out of steam , especially on warmer days.
On a wall-mounted Inverter heat pump, these symptoms can point to several possibilities: a dirty exchanger, obstructed airflow, a sensor that reads incorrectly, or a suboptimal refrigerant charge (often caused by a micro-leak).
Our AirGreen diagnostic: confirm before "touching the charge"
Our approach is always the same: measure, compare, confirm , then intervene. For this Tosot, we proceeded in clear steps:
1) Environmental and emissions verification
Even before the instruments are used, the "terrain" is validated:
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presence of vegetation and debris on the ground near the unit
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nearby objects and surfaces that could partially block airflow
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visual condition of the heat exchanger (condenser), grilles, fins
2) Functional check
We then observed the machine in operation:
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Inverter compressor stability
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cycle consistency
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noise, vibration, fan behavior
3) Refrigeration measurements (pressure readings and parameter readings)
The photo clearly shows our measurement step: service connection with hose (red) at the valves. At this stage, we don't "add" anything: we read .
These readings, combined with the ambient temperature and operating parameters, led us to a cautious but very common conclusion: a weakened efficiency compatible with a slightly insufficient refrigerant charge , often linked to a micro-loss at the level of a fitting (flare) or a valve core.
Intervention: leak repair + leveling according to the identification plate
Once the hypothesis was confirmed, we carried out a complete, clean intervention, in accordance with best practices.
Step A — Checking the connections and sensitive points
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inspection of accessible connections
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checking the service valves and the seals around the fittings
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Validation of the insulation on the refrigeration line (the insulation visible in the photo is a good sign, but it must also be continuous and well sealed )
Step B — Correction of the loss point (micro-leak)
In this type of situation, the most common culprit is:
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a flare that has been slightly affected by hot/cold cycles
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or a valve core that no longer seals perfectly.
We corrected the faulty point and then rechecked the seal. The goal: to stabilize the system and prevent the same problem from recurring in a few weeks.
Step C — Stabilization and upgrading (professional method)
Next, we proceeded with the reconditioning:
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vacuuming (if required depending on the procedure)
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upgrade according to the specifications of the nameplate (without guessing, without “by feel”)
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Final check in real-world operation
Result: restored power, more stable cycles, reassured customer
After the procedure, the difference was immediate:
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Cooler/more efficient air at the indoor unit level
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more stable operation (fewer jolts, fewer variations)
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The system reverts to normal inverter logic: it modulates , instead of compensating by forcing
And above all: the customer regained a feeling of “clean” comfort, the kind you expect from a Tosot wall-mounted heat pump in good condition.
Simple (and very effective) recommendations for this type of installation
In an urban backyard like this one, our advice is practical:
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Clear the area around the outdoor unit
Keep a good amount of space free of plants, pots, or tall grass around the condenser. -
Prevent debris from accumulating at the bottom of the unit
Leaves and dust always end up clogging the heat exchanger. -
Schedule preventative maintenance
Even a high-performance wall-mounted heat pump quickly loses efficiency if neglected (and electricity costs more when the machine compensates).
Why choose AirGreen for a Tosot repair in Montreal?
Because a "quick fix" on an inverter heat pump often ends up costing more. We use:
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measured diagnosis (no approximation)
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correcting the root cause (not just masking the symptom)
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compliant and durable restoration
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advice tailored to the realities of courtyards, balconies and backyards in Greater Montreal