An Urgent Call in the Middle of Winter for a Frozen Wall-Mounted Heat Pump
The Montréal winter doesn’t compromise, and in LaSalle, heating and cooling equipment is put to the ultimate test. It was in this harsh context that we received a call for an emergency repair of a Sanyo wall-mounted heat pump, an outdoor unit mounted high on a brick wall, fully exposed to wind and snow accumulation. The customer reported a significant drop in heating performance and unusual noises coming from the outdoor unit, especially during defrost cycles.
At AirGreen, we understand how essential a reliable HVAC system is, especially when it comes to keeping a home warm during a snowstorm. This service call in LaSalle presented a classic winter challenge: diagnosing and repairing an outdoor unit clearly affected by ice build-up, snow, and potentially a partial refrigerant backup.
Inspection of the Heat Pump: Technical Analysis of the Sanyo Unit
Our certified technician began with a complete visual inspection of the outdoor unit. The Sanyo model in question, firmly mounted on a metal wall bracket, showed significant snow and ice accumulation on top and around the refrigerant connections. The power supply wiring and the insulation around the refrigerant lines showed signs of wear, and the condensate drain was partially blocked by ice.
Technical issues observed during the inspection:
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Partial ventilation blockage due to snow on the front grille.
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Deteriorated refrigerant insulation, exposing the lines directly to freezing temperatures.
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Improper drainage of condensate, contributing to visible icicle formation under the service valve.
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Overly high discharge temperature in heating mode, indicating a potential issue with pressure or the defrost cycle regulation.
Repair Steps for the Sanyo Wall-Mounted Heat Pump
Manual Defrost and System Rebalancing
Before performing any internal work, we carried out a safe defrost of the unit using a low-temperature hot air blower. This step is crucial to prevent thermal shock to the coils or electrical components.
Once the unit was cleared, we:
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Measured the system’s operating pressures using gauges compatible with R410A refrigerant.
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Checked the four-way valve, which appeared to be stuck during mode reversal.
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Inspected the internal electrical connections for signs of moisture-related corrosion.
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Tested the outdoor temperature sensor, which influences the activation of the automatic defrost cycle.
Repairs Performed:
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Replaced the faulty outdoor temperature sensor, which was preventing the defrost cycle from initiating correctly.
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Reinsulated the refrigerant lines with high-density weather-resistant insulation, suitable for humidity and UV exposure.
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Cleared and restored the condensate drain, ensuring proper water flow.
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Adjusted the refrigerant charge of R410A after identifying a slight pressure imbalance.
Results After the Service Call: Comfort Restored Despite Harsh Conditions
After completing all the corrections, the Sanyo heat pump resumed optimal performance. The indoor airflow was once again warm and steady, and the outdoor unit was alternating correctly between heating and defrost cycles. Our final checks confirmed:
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Stable pressures in heating mode.
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Reduced electrical consumption after adjustments.
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Smooth restart of the outdoor fan, with no excessive noise.
Maintenance Tips to Avoid Winter Breakdowns
This case is a clear reminder that even reputable brands like Sanyo can experience failures in winter if the installation isn’t properly maintained. Here are our recommendations to avoid similar issues:
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Regularly clear snow around the outdoor unit.
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Have temperature sensors and defrost components inspected each fall.
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Raise the unit at least 30 cm off the ground to avoid ice blockage.
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Install a protective cover to shield from direct snow and freezing rain.
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Schedule an annual preventive maintenance visit with a certified AirGreen technician.
AirGreen Expertise in LaSalle: A Fast, Efficient and Long-Lasting Intervention
At AirGreen, we respond daily in LaSalle, Montréal, Laval, Longueuil, on the North Shore and South Shore for all types of heat pump repairs, air conditioners, electric furnaces, or central systems. Thanks to our on-site experience and technical know-how, we’re able to diagnose issues quickly, even under extreme weather conditions like this one.
We also offer solutions to modernize or replace older units like this Sanyo, with more efficient models better suited to Québec’s winters.
Why Choose AirGreen for Your HVAC Service Calls?
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Fast service 7 days a week
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Certified technicians trained in advanced diagnostics
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Professional, transparent customer service
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Specialized tools for safe defrosting and pressure testing
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Full coverage across Greater Montréal