A complex service call in the typical urban architecture of Montréal
In the vibrant Plateau-Mont-Royal neighbourhood, every building tells a story, but they all share one common challenge: difficult access. During this recent service call for a Lennox wall-mounted heat pump, our AirGreen technicians were dispatched to service a unit installed high up on the brick wall of a multi-storey residential building, featuring a spiral staircase on the right and a wooden back deck. A typical setting for the area, but one that requires specialized expertise for any HVAC work to be safe and effective.
Initial diagnosis and technical context of the service call
The client, the owner of a duplex, contacted us after noticing a significant drop in performance from their Lennox wall-mounted heat pump, which had been in place for several years. The unit, though still in good physical condition, was no longer providing consistent warm air, even during the cold winter period. The main issue: irregular heating, accompanied by an unusual noise coming from the outdoor unit mounted high up.
Our certified technicians carried out a full inspection. Here are the technical issues identified:
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A light build-up of frost on the outdoor heat exchanger.
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A faulty temperature sensor causing incorrect readings of the room temperature.
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Accumulation of debris inside the unit, disrupting proper airflow.
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Malfunction in the automatic defrost mode.
A complex and secure working environment
Working on a unit mounted several meters above the ground, on the second floor of a typical Plateau building, represents a major logistical challenge. Accessing the outdoor unit required the deployment of our specialized high-access safety equipment.
Our technicians secured the area, set up a work platform, and used fall-arrest harnesses to operate safely. In these types of situations, our experience in dense urban residential environments makes all the difference.
Repair steps for the Lennox heat pump
We followed a methodical approach to ensure a lasting repair:
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Power cut-off and secure disconnection of the unit.
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Full opening of the casing for deep cleaning of the electronic board and air pathways.
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Replacement of the faulty Lennox ambient temperature sensor with an original part, following a resistance test that confirmed the defect.
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Testing of the outdoor fan – no mechanical fault detected.
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Software update of the defrost parameters via the internal programming interface.
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Complete reboot of the unit and functional cycle testing.
Final result: a fully operational Lennox heat pump
Following the repair, the Lennox unit returned to optimal operation. Heating cycles stabilized, and the abnormal noise disappeared. The client immediately noticed a consistent indoor temperature, even during the coldest hours of the day.
Thanks to our precise and prompt intervention, we not only avoided a premature unit replacement, but also improved the energy efficiency of the system.
Unique challenges of Plateau-Mont-Royal: a neighbourhood that demands tailored HVAC expertise
Plateau-Mont-Royal, with its exterior staircases, narrow balconies, brick walls, and systems often located at the back of buildings, presents unique constraints for HVAC companies. At AirGreen, we’re experts in navigating these complex environments.
We’re fully equipped to intervene quickly, even in tight or hard-to-reach spaces, thanks to our specialized tools, experienced team, and strict safety protocols.
Why choose AirGreen for your wall-mounted heat pump repairs in Montréal?
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Certified Lennox and multi-brand technicians
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Recognized expertise in complex urban environments
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Safe high-access repairs, with no damage to façades
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Fast response throughout Montréal, Laval, Longueuil, North Shore and South Shore
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OEM parts and accurate diagnostics with advanced tools
We don’t just repair—we extend the lifespan of your HVAC systems while maintaining high energy efficiency levels.
The importance of regular preventative maintenance to avoid this kind of breakdown
This Lennox heat pump breakdown could have been avoided with proper annual maintenance. A faulty sensor, early signs of frost, declining performance—these issues can all be caught early. That’s why we recommend that our clients in Plateau-Mont-Royal enroll in our HVAC preventative maintenance program.
This program includes:
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Full cleaning of the indoor and outdoor units
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Electrical circuit checks
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Defrost cycle control
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Energy performance analysis
An AirGreen intervention, trust restored
This service call in Plateau-Mont-Royal perfectly illustrates our commitment: delivering reliable, technical HVAC service tailored to Montréal’s architectural reality.
Every service call is an opportunity for us to prove that technical expertise, customer service, and safety can go hand in hand. At AirGreen, we take pride in being the trusted HVAC experts for Plateau residents and the entire Greater Montréal area.