In a condo in Rosemont–La Petite-Patrie , our AirGreen technicians were called to a Goldstar wall-mounted heat pump (mini-split) that was no longer functioning properly: uneven comfort, strange cycling, and a clearly decreased efficiency. The photo shows an indoor wall unit installed high up, a typical residential configuration designed to distribute air to the center of the room with ample clearance.
Even when a machine continues to "blow air," a heat pump can lose a significant portion of its efficiency. And in a neighborhood like Rosemont—where the seasons impose real temperature variations—a drop in performance is immediately noticeable.
The problem reported by the customer
The client described very specific symptoms to us:
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Heating less powerful than usual (and longer heat-up time)
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Uneven cooling depending on the room and the direction of the airflow
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Frequent start/stop cycles (short cycle) at certain times
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A general impression that "the machine is straining" without delivering the expected comfort.
On a wall-mounted Goldstar , these signs often point to a mixture of causes: insufficient maintenance, degraded heat exchange, drainage problems, inaccurate temperature sensors, or control parameters (remote control / card) that no longer correctly read ambient conditions.
Our AirGreen diagnostic, step by step
At AirGreen, we avoid assumptions. We diagnose in a structured way, because a "small" breakdown can hide a more costly problem if left unchecked.
1) Verification of the actual behavior of the indoor unit
We began by observing:
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the opening/closing of the shutter
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ventilation stability
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the response to changes in instructions
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the consistency between the requested temperature and the temperature actually felt in the area
This allowed us to confirm that the unit was functioning, but not achieving its normal performance , especially in heating.
2) Checking the filters, the heat exchanger, and the air circulation
For wall murals, the number one weakness remains air restriction :
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clogged filters
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battery (coil) charged with fine dust
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micro-obstruction that reduces heat exchange
Even if the unit is “eye-clean”, a thin layer is enough to reduce efficiency and cause short cycles.
3) Inspection of drainage and condensate
We then checked:
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slope and condition of the drain
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presence of deposits (biofilm) in the tank
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signs of abnormal humidity
A partially blocked drain can cause erratic behavior, internal protection, and sometimes odors or frost depending on the season.
4) Functional measurements and validation of sensors
Finally, we checked the regulatory logic:
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ambient temperature reading (internal sensor)
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heat exchanger probe consistency
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stability of controls
When a sensor “drifts”, the heat pump may think it has reached the setpoint when the room is still uncomfortable — or vice versa.
The repairs carried out on the Goldstar
After diagnosis, we applied a comprehensive intervention, geared towards “return to performance” (not just a quick fix).
Technical cleaning and restoration of the heat exchanger
We proceeded to:
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deep cleaning of the filters
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controlled dust removal from the battery
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checking the turbine and the areas where dust accumulates (often invisible on the surface)
The result: a more direct airflow, more homogeneous diffusion, and a heat pump that works less to deliver more.
Drainage treatment and condensate securing
We have :
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cleared and stabilized the drainage line
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cleaned areas prone to deposits
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validated flow under real-world conditions
This avoids the return of problems (water, odors, untimely protections).
Recalibration of usage and optimization of settings
Even a good machine can appear “weak” if:
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the direction of the shutter is not optimal
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The (AUTO / HEAT / COOL) mode is not being used correctly as needed.
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The instruction changes too rapidly, which encourages short cycling.
We therefore adjusted the usage parameters with the client so that the Goldstar would perform at its best, without overconsumption.
Results: Comfort restored and performance regained
At the end of the procedure, the difference was immediate:
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more stable and better distributed air
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Improved response time (heating and air conditioning)
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smoother operation , fewer short cycles
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improved comfort without "forcing" the machine
The client took away one key point: it wasn't a single, dramatic breakdown, but rather a series of contributing factors that were eroding performance . And this is precisely the kind of situation where a methodical approach makes all the difference.
What we recommend to prevent it from happening again
For a Goldstar wall-mounted heat pump in a residential environment (condo/house), our recommendations are simple and effective:
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Clean/maintain the filters regularly (especially during heating season)
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Perform periodic technical maintenance (battery, turbine, drainage)
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avoid extreme variations in setpoint over short periods
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Watch for subtle signs: loss of power, less homogeneous air, abnormal humidity
AirGreen in Rosemont–La Petite-Patrie: Residential HVAC repair, no guesswork
Our goal isn't just to "get a machine running again." It's to ensure reliable comfort , increase performance, and restore the customer's confidence that their heat pump will keep up with the seasons in Montreal.