A flat roof intervention for a broken heat pump in the middle of spring thaw
At AirGreen , we frequently receive calls from Montreal clients whose heating and cooling systems are showing signs of weakness as winter approaches. This is exactly what happened in the Côte-des-Neiges–Notre-Dame-de-Grâce neighborhood, where a building owner contacted us about a Sharp ECO Inverter wall-mounted heat pump installed on the roof. The unit, normally reliable and efficient, suddenly refused to switch effectively between heating and cooling mode.
Initial diagnosis: abnormal pressure in the refrigeration circuit
Upon our arrival, our technicians installed service pressure gauges on the Sharp heat pump connections to measure the R-410A refrigerant pressure. The verdict was quickly reached: the suction pressure was abnormally low, indicating a probable lack of refrigerant gas in the circuit.
The outdoor unit appeared pristine—no signs of oil leaks or visible corrosion. However, a thorough inspection revealed slight seepage from a flare connection , likely caused by winter temperature fluctuations and copper expansion .
Repair steps: rigor, method and safety
1. Recovery of residual refrigerant
Before any intervention, we carried out the complete recovery of the refrigerant gas using a certified pump, in accordance with current environmental standards.
2. Disassembly and inspection of the fitting
The defective flare fitting was disassembled, cleaned, and replaced with a new, perfectly calibrated fitting. We also added a drop of POE oil to improve the seal when tightening.
3. Nitrogen leak test
The system was then pressurized to 400 psi with dry nitrogen for 30 minutes. No pressure loss was detected—proof that the repair was sound.
4. Deep vacuum and precise refill
A full vacuum to -30 inHg was performed to remove all traces of moisture. The R-410A refrigerant was then recharged to the nearest gram according to Sharp specifications.
Final checks: optimal performance restored
Once the heat pump was restarted, our technicians measured:
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A stable suction pressure at 120 psi;
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An indoor blowing temperature of 8.2°C;
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Nominal power consumption and no compressor overload.
The Sharp ECO Inverter system , renowned for its Plasmacluster Ion technology (air purification), has resumed quiet and stable operation. The customer was able to notice an immediate return of thermal comfort in his home, both for heating and air conditioning.
AirGreen Tips for Sharp Heat Pumps
Sharp appliances, especially those in the ECO Inverter series, are designed to offer excellent energy efficiency, but they require regular maintenance to ensure their longevity:
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Clean the internal filters every 6 weeks;
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Inspect exterior fittings at the start of each season;
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Check refrigerant pressure every 2 years;
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Avoid blocking the ventilation grilles of the outdoor unit.
Our certified technicians cover all of Greater Montreal , including Laval, Longueuil, the North Shore and the South Shore , to offer fast, precise and guaranteed service on all major brands: Sharp, Fujitsu, Gree, Midea, Lennox, and more.
Local and recognized HVAC expertise
Whether for installation, repair or preventative maintenance , AirGreen remains the Montreal benchmark for residential and commercial HVAC systems . Each service call is handled with the same attention to detail: accurate diagnosis, compliant intervention and performance monitoring.
In Côte-des-Neiges–Notre-Dame-de-Grâce , as everywhere else, our work on flat roofs demonstrates our ability to adapt to urban environments and our commitment to maintaining each heat pump at its optimal performance — winter and summer.