Polar Bear HVAC System Repair in Côte-des-Neiges (Montreal)

A double failure on a flat roof in the middle of summer

In the heat of June, our AirGreen team was contacted by a building owner in Côte-des-Neiges (Montreal) whose Polar Bear HVAC system was no longer properly cooling several apartments. Two outdoor condensers installed on the building's flat roof appeared to be working, but the air blown inside was lukewarm, even hot. A typical case of progressive failure, often linked to a lack of maintenance and prolonged exposure to the sun .

Initial diagnosis: loss of performance and abnormal pressure

Upon arrival, we performed a complete visual inspection of both Polar Bear units.
Our first observations:

• Accumulation of dust and debris on the condenser fins , reducing heat exchange.

• Pipe insulation deteriorated by sun and moisture, leading to refrigeration losses.

• Traces of oil on a flare fitting , a potential sign of a micro-leak of refrigerant .

We then connected our digital pressure gauges to measure the circuit pressures. The results confirmed our hypothesis: low pressure on the low side , indicating a lower than normal amount of refrigerant .

Step 1: Leak detection and repair

Using an electronic leak detector , we identified a slow leak at the suction connection of the older unit.
Procedure performed:

1. Silver re-solder on the copper pipe junction.

2. Nitrogen leak check at 300 psi to ensure no secondary leaks were present.

3. Complete vacuum of the circuit (500 microns) to eliminate all traces of humidity.

4. Recharge with R410A refrigerant according to factory specifications.

Once the charge was restored, we noted an immediate return to normal pressures and an interior blowing temperature of 8°C — proof that thermodynamics was resuming its optimal cycle.

Step 2: Complete cleaning of the condenser and fins

Condensers, exposed on a flat roof, experience a rapid accumulation of dust and asphalt particles. We therefore have:

• Cleaned the coils with a mild alkaline product designed for aluminum surfaces.

• Degreased the fan and tightened the protective grille.

• Checked the fan motor , the bearings were starting to show slight play.

• Applied anti-corrosion protection to copper sections and steel connections.

This cleaning improves heat dissipation and extends compressor life —an often overlooked but vital element for system performance.

Step 3: Insulate and finish the wiring

We noticed that the power wires and refrigeration lines connecting the units to the building were partially exposed.
Our technicians replaced:

• UV foam insulation with a reinforced model for commercial roofing.

• The aging fixing collars are made of stainless steel fasteners.

• Outdoor wiring , using a black protective sheath resistant to UV rays and humidity.

This step, although discreet, guarantees electrical safety and reduces the risk of short circuits, particularly during rainy periods.

Performance test and final calibration

Once the repair was complete, we ran a full cooling cycle on both systems simultaneously.
Results :

• Pressures meet Polar Bear specifications.

• Discharge temperature stabilized at 55°C.

• Balanced power consumption between the two units.

• Air blown at 7.8°C at the outlet of the interior evaporator .

Both systems operated optimally, without vibration or abnormal noise.

Preventive advice given to the client

Before leaving the premises, our team provided the client with a detailed maintenance report with specific recommendations:

• Clean outdoor condensers twice a year , in spring and late summer.

• Visually check the insulation at each change of season.

• Schedule an annual pressure inspection to prevent microleaks.

These simple actions can extend the life of the system by 5 to 8 years and avoid costly breakdowns during a heatwave.

AirGreen: HVAC expertise serving Montreal buildings

For over a decade, AirGreen has been operating throughout Montreal, Laval, Longueuil, on the North Shore and the South Shore for the maintenance, repair and installation of HVAC systems.
Our certified technicians combine technical rigor and attention to detail, whether for:

• A refrigerant leak,

• A compressor failure,

• An electrical problem,

• Or a complete installation on a flat roof.

Every service call is treated with the same priority: restoring the comfort, safety, and energy efficiency of our customers' HVAC systems.

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Result: efficiency restored, customer reassured

A few hours after our intervention, the owner confirmed that the interior temperature of the accommodations had stabilized , and that the two Polar Bear units were once again running quietly and efficiently.
Another example of AirGreen's expertise: combining precise diagnosis , lasting repair and proactive prevention to ensure optimal performance of HVAC systems in Montreal.