A delicate service call in a typical Montreal backyard
At AirGreen , we are often called upon to work in urban settings where space is limited and installations require a methodical approach. This is precisely what our team encountered during a service call for a Sharp wall-mounted heat pump in the Rosemont–La Petite-Patrie neighborhood of Montreal.
The client contacted us after noticing that their Sharp system had stopped producing cold air for several days. The situation was all the more urgent as the apartment was south-facing, where indoor temperatures exceeded 30°C.
Initial inspection and field findings
The outdoor unit, mounted high on a red brick wall above the rear balcony, showed obvious signs of wear:
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Accumulation of dust and debris on the condenser.
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Exposed wiring and slightly damaged insulation.
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Clicking noise from compressor when starting.
Our team installed a secure ladder to access the wall unit, ensuring the stability of the metal support. The Sharp compressor—a 12,000 BTU , R-410A-compatible unit—appeared to be running intermittently.
After connecting our measuring instruments, the diagnosis revealed:
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Abnormal low refrigerant pressure ;
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A high discharge temperature , a sign of an overloaded compressor;
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A starting capacitor at the end of its life (capacitance measured at 4 µF instead of 7.5 µF).
Steps of repair
Our intervention took place in three specific stages:
1. Checking the refrigeration circuit
We first performed a dry nitrogen leak test , confirming the presence of a microleak at a flare fitting on the liquid line. This type of problem is common in wall-mounted installations exposed to vibration and temperature fluctuations.
2. Repair and replacement of defective components
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Tightening and re-brazing of the flare fitting with silver brazing.
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Replacement of the starting capacitor , genuine Sharp part, guaranteeing the restart of the compressor without electrical overload.
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Complete system recharge with R-410A refrigerant according to equipment pressure ratings.
3. Final cleaning and calibration
To finalize, we steam cleaned the condenser to optimize heat transfer, then checked the power consumption in operation . The final measurements demonstrated a return to optimal performance , with a temperature difference of 12 °C between the incoming air and the supply air.
Result: comfort restored and efficiency regained
As soon as it was restarted, the customer immediately noticed a noticeable difference:
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Rapid cooling of the main room;
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Operational silence restored;
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Thermal stability without temperature fluctuation.
We took the time to recommend annual preventative maintenance , which is essential for wall units installed in urban environments exposed to dust and debris.
AirGreen Tips for High Wall Installations
Systems like this one, fixed halfway up the facade, have special features that should not be overlooked:
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Vibrations and microleaks : Thermal cycles can loosen fittings; an annual inspection prevents gas loss.
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Condensation : Good drainage prevents water stagnation which can corrode supports.
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Regular cleaning of the condenser : it improves energy efficiency by more than 10%.
With these simple precautions, the life of your Sharp wall-mounted heat pump can be extended by several years.
The AirGreen commitment in Montreal and beyond
At AirGreen , we combine technical rigor and attention to detail in every intervention. Our certified technicians operate throughout Montreal, Laval, Longueuil, the North Shore and the South Shore , for fast, precise and guaranteed repairs.
Whether it's a refrigerant leak , a noisy compressor , or a faulty electronic board , our mission remains the same: to restore the comfort and performance of your HVAC system , while extending its useful life.
Summary of the intervention:
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Brand: Sharp
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Type: Wall-mounted heat pump (12,000 BTU)
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Location: Rosemont–La Petite-Patrie, Montreal
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Problem: Decreased performance, leakage, faulty capacitor
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Solution: Repair the fitting, replace the capacitor, recharge R-410A
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Result: Efficiency and comfort restored
AirGreen: your HVAC partner in Montreal
A well-maintained Sharp heat pump can provide years of reliable performance. If your unit is showing signs of weakness, frost, or loss of cold air , contact AirGreen today. We respond quickly to diagnose and repair any make or model of wall-mounted heat pump.