A PolarBear wall-mounted heat pump breaks down in the middle of a Montreal winter
At AirGreen , we service wall-mounted heat pumps in Montreal every week, in both central and residential areas. This particular service call involved a PolarBear wall-mounted heat pump installed on the side of a house in the Rosemont–La Petite-Patrie borough, a typical neighborhood of brick buildings exposed to wind and snow accumulation.
The customer contacted us urgently following a near-total loss of heating after a series of very cold nights. Despite a high setting on the wall thermostat, the indoor temperature remained stable and the unit operated erratically, alternating between short heating cycles and complete shutdowns.
In Montreal 's climate, this type of breakdown can quickly become critical, especially when the wall-mounted heat pump is the main source of heating.
Description of the inspected PolarBear wall-mounted heat pump
The machine in question was a PolarBear wall-mounted heat pump , a single-zone system commonly installed in single-family homes and duplexes in Montreal.
Configuration observed on site:
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Machine type : wall-mounted heat pump (mini-split)
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Brand : PolarBear
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Estimated capacity : approximately 12,000 BTU
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Outdoor installation : unit mounted on wall brackets, above the foundation
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Indoor installation : wall-mounted unit in the main living area
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Approximate age : 6 to 8 years old
Although PolarBear heat pumps are designed for the Canadian climate, their reliability depends heavily on the quality of the installation , outdoor exposure , and maintenance performed over the years.
Symptoms reported by the customer and observed on site
Even before we connected our diagnostic instruments, several signs indicated a problem more serious than a simple adjustment:
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Warm or cool air is blown in heating mode.
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Very short cycles of the external compressor
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Persistent frost present on the outdoor unit
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Unusual fan noise during startup
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Ineffective or incomplete defrosting
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Frequent machine restarts
In an urban environment like Montreal , where wall-mounted heat pumps are often installed close to masonry walls, these symptoms are frequently related to problems with defrosting , temperature probes , or electronic components .
HVAC diagnostic process performed by AirGreen
At AirGreen , we systematically apply a structured diagnostic approach to avoid any unnecessary repairs.
Mechanical and environmental inspection
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Checking the clearance around the outdoor unit
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Inspection of the wall bracket and stability
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Analysis of ice accumulation and drainage
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Checking the outdoor fan and its motor
Electrical and electronic checks
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Reading internal error codes
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Measurement of supply voltages
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External electronic board check
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Temperature and defrost sensor testing
Refrigeration check
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Refrigerant pressure control
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Analysis of compressor behavior
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Performance check in heating mode
These steps helped to identify a combined failure involving a faulty defrost sensor and internal fouling that compromised the unit's ability to properly manage winter cycles.
Main problem identified on the PolarBear heat pump
The root of the problem stemmed from a faulty outdoor temperature sensor , which was sending incorrect information to the electronic board. The result:
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The system was triggering inadequate defrosting cycles.
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The compressor never reached a stable speed
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The heat pump went into thermal protection mode
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The indoor heating was becoming insufficient
In Montreal, this type of failure is common when sensors are exposed to the elements for several winters without preventative maintenance.
Repair work carried out by AirGreen
After clearly explaining the situation to the client, our team carried out a complete and targeted repair , including:
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PolarBear defrost sensor replacement
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Thorough cleaning of the outdoor unit
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Verification and securing of electrical connections
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Reset and recalibrate the electronic board
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Extended test in heating mode using simulated negative temperature
Each step was carried out on site, without unnecessary delay, in order to quickly restore the thermal comfort of the dwelling.
Immediate results after repair
Once the repair was complete, the improvements were immediately measurable:
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Smooth and stable compressor restart
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Continuous and efficient heating cycles
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Automatic defrosting function
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Constant hot air to the indoor unit
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The indoor temperature returned to a comfortable level in less than an hour.
The customer quickly noticed a significant difference , both in terms of comfort and operating noise.
Common mistakes to avoid with a wall-mounted heat pump in Montreal
This intervention highlights several errors that we regularly observe during our service calls in Montreal , Laval , on the North Shore and the South Shore :
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Neglecting the annual maintenance of the outdoor unit
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Allow snow and ice to accumulate under the device
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Ignoring unstable heating cycles
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Postponing a service call despite obvious signs of failure
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Assuming that a lack of heat is solely linked to extreme cold
A well-maintained wall-mounted heat pump is perfectly capable of efficiently heating a Montreal residence, even during periods of extreme cold.
Why entrust the repair of your wall-mounted heat pump to AirGreen
At AirGreen , we specialize in HVAC repair and work daily on wall-mounted heat pumps of various brands, including PolarBear , in Montreal , Laval , Longueuil , on the North Shore and the South Shore .
Our approach is based on:
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Accurate diagnoses
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Lasting repairs
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A thorough understanding of local climate constraints
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Clear communication with each client
Each service call is treated as a unique case, with particular attention paid to the actual performance of the system.