A service call in the heart of Ahuntsic-Cartierville for a wall-mounted heat pump that was no longer heating properly
In a residential home in Ahuntsic-Cartierville, in Montreal, our AirGreen team intervened for a ComfortStar wall-mounted heat pump installed high on an interior wall, very close to a concrete ceiling. The client had contacted us because the device seemed to be working but was not producing the expected comfort. The indoor unit started, the louvers opened, the ventilation was noticeable, but the heat distributed in the room remained insufficient and irregular.
This type of situation is common with older or poorly maintained wall systems. A heat pump can give the impression of running while gradually losing its actual capacity. The ventilation may work, the indicator light may remain normal, yet the system can suffer from a sensor problem, clogging, air restriction, refrigerant shortage, poorly drained condensate, or unstable communication between the indoor and outdoor units.
The installation had several important particularities. The wall unit was placed in an open living space, above an occupied area, with an exposed concrete ceiling that could influence heat distribution. The presence of a wall thermostat and nearby controls also indicated a setup where comfort depended on accurate temperature reading, stable airflow, and proper positioning of the louvers. In this context, our diagnosis could not be limited to checking if the device was blowing air; it was necessary to measure, observe, and understand the complete system behavior.
Symptoms observed before our intervention
The client had noticed that the wall-mounted heat pump was no longer responding as before. In heating mode, the room took much longer to reach the requested temperature. At times, the blown air seemed lukewarm rather than hot, and the device could run for a long time without giving a feeling of stable comfort.
The reported symptoms were as follows:
- low heating despite a normal setting;
- indoor ventilation present, but insufficient performance;
- longer cycles than usual;
- ambient temperature difficult to stabilize;
- feeling that the wall unit was straining without producing enough heat;
- discomfort in the main room, especially near cold walls and openings.
These symptoms can have several causes. On a wall-mounted heat pump, it is possible that the indoor unit is dirty, the filters restrict airflow, the fan is dirty, the temperature sensor misreads the environment, the refrigerant charge is insufficient, or the outdoor unit no longer transfers heat properly.
At AirGreen, we approach every HVAC repair methodically. The goal is not to replace a part at random, but to find the exact link between the symptom experienced by the client and the technical behavior of the machine.
First step: inspection of the indoor unit
The wall unit was installed quite high, which is common in Montreal homes where the goal is to maximize air diffusion without losing floor space. However, a high installation requires special attention to maintenance. Fine dust, deposits on filters, and fan dirt can accumulate without being visible at first glance.
We started by checking:
- the condition of the filters;
- the cleanliness of the indoor evaporator;
- the opening and movement of the louvers;
- the airflow at the outlet;
- the presence of odors or moisture;
- the condition of the ventilation fan;
- the device's response to mode changes;
- temperature reading near the unit.
The inspection quickly showed that the airflow was not optimal. The filters and some internal areas had enough dust accumulation to reduce performance. It was not a complete blockage, but enough to impair heat exchange. When an indoor unit does not allow air to pass properly, the system may seem to work, but the heat produced is not effectively distributed in the room.
Ventilation and blowing temperature diagnosis
After the visual inspection, we proceeded with operational measurements. A wall-mounted heat pump must be evaluated by observing the difference between the air intake and the blown air. This difference helps determine if the system is actually transferring heat or just ventilating.
We checked the return temperature, the blowing temperature, the stability of the airflow, and the unit's response after a few minutes of operation. The result indicated weakened performance, but not a complete failure. The machine could still produce heat, but distribution was compromised by a combination of dirt buildup and unstable regulation.
This detail is important: a customer might think the compressor is dead when the heat seems insufficient. However, in many cases, the problem first comes from the indoor unit. If air does not pass well through the heat exchanger, the heat pump cannot deliver its normal performance, even if the outdoor unit is working.
Verification of controls and sensor
The device was installed near wall controls, which led us to check the consistency between the setpoint, ambient temperature, and unit response. A poor temperature reading can cause too-short cycles, premature stops, or a feeling of insufficient heating.
We tested different settings:
Heating mode
We forced a heating demand to confirm the response of the indoor and outdoor units. The start-up was present, but the temperature rise remained slow.
Ventilation mode
The ventilation mode allowed us to evaluate airflow without immediate influence from the compressor. This step confirmed that airflow needed improvement.
Response to setpoint changes
We observed whether the device responded correctly when the setpoint was changed. Communication seemed functional, but the unit needed refurbishment to regain stable performance.
Intervention performed: technical cleaning and reconditioning
Once the probable causes were identified, we carried out a complete intervention on the indoor unit. The goal was to restore airflow, ensure safe operation, and validate performance after correction.
Cleaning of filters and internal surfaces
The filters were removed, cleaned, and inspected. On a wall-mounted heat pump, the filters are often the first barrier against dust. When saturated, air circulates less effectively, heat exchange decreases, and the fan motor works harder.
Cleaning of the indoor heat exchanger
We cleaned the accessible areas of the heat exchanger to reduce air restriction. A dirty heat exchanger can cause capacity loss, bad odor, residual humidity, and irregular operation.
Turbine inspection
The indoor turbine is one of the most often overlooked components. Even when the filters seem acceptable, the turbine can accumulate a layer of dust that reduces airflow. In this case, its condition warranted special attention because the customer was precisely feeling a lack of blowing power.
Inspection of the condensate drain
Even though the call was mainly about a heating problem, we inspected the condensate drainage. A partially blocked line can cause leaks in air conditioning mode and create moisture inside the unit. At AirGreen, we take advantage of this type of intervention to prevent seasonal problems before they become urgent.
Inspection of the outdoor unit and refrigeration circuit
A wall-mounted heat pump repair cannot be completed without checking the outdoor unit. Even when symptoms are felt indoors, performance depends on the compressor, outdoor fan, outdoor coil, refrigerant, and electrical connections.
We therefore checked:
- starting of the outdoor unit;
- operation of the fan;
- general condition of the condenser;
- abnormal vibrations;
- signs of unusual frost;
- accessible electrical connections;
- consistency of pressures and temperatures according to conditions;
- no obvious sign of a major leak.
The outdoor unit was responsive, but the overall performance confirmed that indoor maintenance was necessary and that follow-up should be recommended if efficiency declined again. In several buildings in Montreal, especially in Ahuntsic-Cartierville, wall systems are heavily used: supplemental or primary heating depending on the season, summer air conditioning, frequent transitions in spring and fall. This continuous use makes maintenance more important.
Result after the intervention
After cleaning, inspections, and adjustments, we restarted the wall-mounted heat pump in heating mode. The airflow was more stable, the blowing temperature improved, and the room began to respond more quickly to the setpoint. The customer noticed a clear difference in comfort.
The results obtained:
- better air circulation;
- more consistent heating;
- reduced time needed to heat the room;
- more stable operation;
- reduced risk of internal overheating;
- cleaner indoor unit;
- customer reassured about the system's condition.
This type of repair shows that a comfort issue does not always mean the device needs to be replaced. A well-executed technical intervention can restore the performance of an existing wall-mounted heat pump, especially when the machine still responds properly to controls.
Common mistakes to avoid with a wall-mounted heat pump
During this call in Ahuntsic-Cartierville, we also reminded the client of some essential points to preserve the performance of their system.
Neglecting filter cleaning
Filters must be cleaned regularly, especially in a living space occupied daily. Dust, pet hair, fine particles, and seasonal residues quickly reduce airflow.
Believing that ventilation alone means everything is fine
A heat pump can blow air without delivering sufficient performance. You need to check the blowing temperature, cycle duration, and actual capacity to reach the setpoint.
Blocking air diffusion
Furniture, lighting fixtures, decorations, or items placed too close to the unit can affect air distribution. In a room with a high ceiling or exposed concrete, air circulation must be particularly well controlled.
Waiting for a leak or a complete shutdown
A drop in performance is already a warning sign. The faster the intervention, the more it is possible to avoid costly breakdowns or premature replacement.
Why the unit’s location affects comfort
In this Ahuntsic-Cartierville home, the wall unit was installed in an open space under a concrete ceiling. This type of environment can affect comfort perception. Concrete retains cold or heat depending on the season, and warm air naturally rises to the top of the room. If the airflow is weakened or the louvers are not properly oriented, the client may feel uncomfortable temperatures even if the device is working.
That’s why we paid attention to the direction of the airflow. In heating mode, it is often better to direct the air downward to better distribute heat in the occupied area. Poor orientation can cause warm air to accumulate near the ceiling, especially in spaces with higher ceilings.
The importance of regular HVAC maintenance
A wall-mounted heat pump used year-round should be maintained periodically. Maintenance is not only to keep the device clean; it also helps detect signs of weakness before a breakdown.
Proper HVAC maintenance allows you to:
- maintain good airflow;
- reduce electrical consumption;
- extend the lifespan of the ventilation motor;
- limit odors;
- prevent condensate leaks;
- improve comfort;
- protect the compressor;
- quickly identify anomalies.
At AirGreen, we regularly intervene for similar services in Montreal, Laval, Longueuil, on the North Shore, and the South Shore. Each building has its particularities: condo with high ceilings, multi-story house, old duplex, extension built later, commercial space, rental unit, or family residence. Our diagnosis always adapts to the reality of the location.
A precise HVAC repair to restore stable comfort in Montreal
This service call in Ahuntsic-Cartierville clearly illustrates our way of working. The ComfortStar wall-mounted heat pump was not completely stopped, but it was no longer fulfilling its role properly. The client felt a loss of comfort, and the technical signs confirmed a drop in performance mainly related to air circulation and the condition of the indoor unit.
Our intervention involved cleaning critical components, checking ventilation, controlling the controls, inspecting the outdoor unit, and validating performance after restarting. The result: a more stable system, better air distribution, and a room gradually regaining the expected comfort.
For a wall-mounted heat pump repair, a heating problem, a drop in performance, a smell, a water leak, a noise, or an electrical failure, AirGreen offers thorough service in Greater Montreal. We serve Montreal, Laval, Longueuil, the North Shore, and the South Shore with a professional, clear, and solution-oriented approach focused on sustainability.
A heat pump that is not working as well as before should not be ignored. A quick inspection can make the difference between simple technical maintenance and a major repair. In this specific case, the intervention in Ahuntsic-Cartierville restored the device to more consistent performance and gave the client well-deserved peace of mind.