A heat pump cramped under house siding
At AirGreen , we are often called upon to work on residential installations where the outdoor unit of the wall-mounted heat pump has been placed in a confined space , sometimes under a balcony or, as in this case in Sainte-Julie , partially under the house's aluminum siding. While this configuration protects against snow and rain, it limits compressor ventilation and can cause long-term performance problems.
The customer contacted us after noticing that his LG heat pump was no longer maintaining a stable indoor temperature. In the summer, it had difficulty cooling, and in the winter, the heating seemed noticeably weak.
Diagnosis: lack of ventilation and refrigeration pressure problem
Upon arrival, we conducted a thorough inspection. The outdoor unit, although clean and in good visual condition, was enclosed under a wall overhang leaving barely six inches of clearance above the fan. This lack of clearance prevented hot air from being properly exhausted during the operating cycle, causing the compressor to overheat .
Refrigeration pressure measurements revealed:
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Abnormally high suction pressure , typical of air backflow.
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Unstable discharge pressure , confirming thermal imbalance.
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Air outlet temperature too high , reducing heat transfer capacity.
We also noticed slight oxidation on the electrical connectors , a result of condensation trapped by the lack of air circulation.
Intervention: Restore circulation and optimize performance
Our technicians carried out a series of specific interventions:
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Partially moved the outdoor unit forward to clear the top and side airflow. We added anti-vibration shims to stabilize the base on the existing concrete slab.
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Thorough cleaning of the condenser coil with AirGreen Pro-Clean biodegradable cleaner, removing accumulated dust and debris.
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Checking and resealing electrical connections , then applying a dielectric protector against humidity.
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R-410A refrigerant check : charge was correct, no leaks detected.
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Performance test after restart : immediate improvement in pressure and airflow.
Thanks to this repositioning and complete maintenance, the LG heat pump has regained optimal performance , once again reaching the target temperature without overheating.
Result: restored efficiency and secure installation
After intervention, the customer noticed:
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A significant reduction in operating noise .
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Better energy efficiency , the machine quickly reaches the set temperature.
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Compressor stability even during long periods of operation.
We recommended maintaining a minimum clearance of 30 cm above and around the unit and never storing objects (such as a garden hose or outdoor furniture) in the immediate vicinity, to avoid obstruction of airflow.
AirGreen Recommendations for Recessed or Semi-Concealed Units
Installations under structures or in recesses require special attention:
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Ensure adequate ventilation : the condenser must be able to freely draw in and discharge air.
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Monitor thermal cycling : Frequent shutdowns may indicate overheating.
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Schedule annual preventative maintenance , especially before extreme seasons.
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Inspect electrical supports and cables to prevent corrosion.
Our AirGreen certified technicians have the necessary tools to optimize this type of installation while respecting the architectural constraints of South Shore homes.
A local, fast and specialized service
Thanks to our mobile team based in Greater Montreal, we respond quickly in Sainte-Julie , Boucherville , Brossard , Longueuil , as well as on the North Shore and Laval . Our priority: ensuring the longevity and energy performance of your HVAC systems.
At AirGreen , every service call is an opportunity to demonstrate our technical expertise and attention to detail—qualities that make us a leader in LG wall-mounted heat pump maintenance and repair across the metropolitan area.