An outdoor unit in trouble after years of exposure
When a customer from Saint-Constant , on the South Shore of Montreal, contacted us about a breakdown of his wall-mounted heat pump , the diagnosis was going to be complex. His outdoor unit, brand R , showed obvious signs of wear: deformed fins, dull paint, exposed wiring. The unit, installed for more than ten years, had stopped producing heat at the beginning of the season.
At AirGreen , we know that a breakdown in an aging wall-mounted heat pump is never trivial: beyond a simple lack of efficiency, it is often an indicator of an imbalance between the compressor, the refrigeration circuit and the electronic components.
Diagnosis: an overloaded compressor and a blocked circuit
Upon our arrival, the technician checked the electrical voltage and the compressor startup . Although the current reached the correct intensity, the unit was unable to maintain the required pressure in the circuit. A pressure measurement at the manifold confirmed the presence of a significant refrigeration charge difference .
After opening the side panel, an inspection of the refrigerant circuit revealed a buildup of oil and metal debris in the discharge line—typical of internal compressor wear . This type of obstruction restricts the flow of refrigerant and can cause the unit to gradually overheat .
Thermal analysis of the electronic board also revealed a faulty defrost resistor , preventing the machine from defrosting correctly in heating mode.
Repair steps: expertise and complete upgrade
1. Dismantling and cleaning the refrigeration circuit
After recovering the residual refrigerant, our team disassembled the flare fittings and thoroughly cleaned the lines using a dry nitrogen flush . This process removes internal deposits and restores refrigerant circulation.
2. Replacing the compressor
The compressor, which was clearly damaged, was replaced with a model of the same capacity compatible with R410A , meeting the original specifications. This step included a new filter drier and a leak test of the circuit before putting it back into service.
3. Renovation of electrical connections and protection of wiring
The cables visible on the facade have been reorganized and sheathed , thus avoiding the risks of short circuits and water infiltration. A rigid protective box has been added to extend the life of the connection.
4. Recharging, calibration and performance testing
Once the system was evacuated, the technician injected the exact amount of R410A refrigerant indicated on the nameplate. After restarting, the heat pump displayed balanced pressures, a stable hot blow at 42°C , and reduced noise levels thanks to the new insulation.
Result: restored efficiency and secure installation
Thanks to this targeted refurbishment , the R wall-mounted heat pump has regained its initial efficiency. The outdoor unit, mounted on a reinforced wall bracket, now operates without excessive vibration. The customer, who was considering a complete replacement, was able to extend the life of his unit for several more seasons.
We also recommended:
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an annual preventive inspection ,
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a complete cleaning of the interior unit ,
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and checking wall fixings exposed to the weather.
The importance of preventive maintenance on the South Shore
The South Shore 's climate, from harsh winters to humid summers, puts a strain on HVAC systems. A small leak or internal obstruction can quickly lead to costly breakdowns. At AirGreen, we emphasize the importance of regular pressure testing and professional cleaning , especially for heat pumps that are more than 8 years old.
AirGreen: Your Trusted HVAC Repair Partner
Our certified technicians operate in Montreal, Laval, Longueuil, the North Shore, and the South Shore , offering fast, accurate service that meets Quebec's environmental standards. We repair all major brands— Daikin, Fujitsu, Gree, Goodman, Midea, Sharp, Lennox, and more —with a constant focus on performance and durability .
Whether it's a leak, a faulty compressor or an electrical failure , we provide concrete solutions that bring your system back to life without compromising on quality.