An old wall-mounted heat pump that still worked but no longer delivered the expected comfort
In Chomedey, in a residential home in Laval, our AirGreen team responded to an HVAC service call on a wall-mounted Airwell heat pump installed high up near the ceiling, in a configuration typical of older wall units. At first glance, the indoor unit still seemed operational: it turned on, responded to commands, and produced some airflow. However, the client had noticed for some time a significant drop in performance, less cold air during cooling, a slow response at startup, and a general impression that the machine was “working” without really improving the room’s comfort.
This type of situation is common with older wall-mounted heat pumps. The problem is not always a complete breakdown. Sometimes, the device continues to operate partially, which can give the impression that it is simply less powerful than before. In reality, several factors can be involved: a dirty evaporator, a saturated filter, an unbalanced indoor fan, an inaccurate temperature sensor, a partially blocked condensate drain, poor air circulation, aging electronic components, or reduced performance related to the refrigerant circuit.
In this specific case in Chomedey, the goal was not to immediately replace the machine but to understand if a wall-mounted heat pump repair could reliably and safely extend its lifespan. At AirGreen, we always prioritize a structured diagnosis before recommending a solution. An old unit can sometimes be effectively restored, provided the main components are still functional and the repair makes technical sense.
An Airwell unit installed very high: access that influences the diagnosis
The first notable feature was the position of the indoor unit. Installed very close to the ceiling, in a corner of the wall, the heat pump had little upper space for access to panels and internal components. This setup often complicates maintenance and diagnosis work, especially when the device is old and the plastics have become more fragile over time.
Our technicians proceeded carefully to avoid damaging the front panel, retention clips, and air vents. On older wall units, opening too abruptly can break a part that is sometimes no longer easily available on the market. That’s why each step was carried out methodically: visual inspection, checking the general condition of the casing, partial opening, filter check, observation of the indoor coil, and ventilation test.
The yellowed appearance of the unit also indicated a long period of use. This is not necessarily a problem in itself, but it suggests the machine has probably gone through several cooling and heating seasons. In the Montreal, Laval, Longueuil, North Shore, and South Shore regions, wall units are heavily used: cooling in summer, supplemental or main heating during colder periods, and extended operation during transitional seasons.
Reported symptoms: less cold air, low airflow, and irregular operation
The client described three main symptoms:
- the blown air seemed less cold than before;
- the airflow appeared weak, even at high speed;
- the unit took a long time to stabilize the room temperature.
These signs generally point the diagnosis toward two main causes: an air circulation problem or a heat transfer problem. In a wall-mounted heat pump, the two are closely linked. If air does not properly pass through the indoor evaporator, the device quickly loses efficiency. Even if the compressor works, the room does not receive the actual power the machine should provide.
Our technicians also checked if the unit produced unusual noises, vibrations, damp smells, or signs of abnormal condensation. In this case, no major noise indicated a defective motor, but the accumulation of dust and deposits inside the unit was significant enough to affect performance.
Complete HVAC diagnosis: identifying the cause before replacing parts
Filter and evaporator inspection
The first step was to check the filter. A dirty filter can significantly reduce airflow and make the machine work unnecessarily hard. On this Airwell wall-mounted heat pump, the filter showed a notable accumulation of fine dust. This type of deposit is not always visually dramatic, but it is enough to limit air exchange, especially on an old unit whose fan no longer has the same efficiency as on day one.
Next, we inspected the indoor coil. The evaporator showed signs of dirt buildup, particularly between the fins. When dust, moisture, and indoor air particles accumulate on the coil, air circulation decreases and cold transfer is less effective. The result is very tangible for the occupant: the heat pump blows air but no longer cools properly.
This situation can also cause excessive condensation, water droplets, unpleasant odors, or even ice on certain parts of the system if conditions are right. Even when there is no visible leak, a dirty evaporator is often the source of persistent discomfort.
Indoor fan check
The indoor fan was then tested at several speeds. The fan wheel was functional, but its performance was reduced by dirt buildup. In wall-mounted heat pump service calls, we often see this situation: the motor runs, so the device seems “on,” but the turbine does not move enough air to ensure effective cooling.
A dirty turbine can also create slight imbalance, generate rubbing noise, or send air unevenly into the room. In this case, the main problem was mainly the loss of airflow. We therefore proceeded with targeted cleaning of accessible areas while respecting the mechanical limits of the device.
Condensate drain check
Another essential step was checking the drain. A wall-mounted heat pump produces condensation in cooling mode. This water must drain properly. When the drain is partially blocked, water can stagnate in the indoor tray, cause odors, increase humidity around the unit, and in some cases, cause leaks.
In Chomedey, the drain was not completely clogged, but its flow was not optimal. We performed cleaning and checked the drainage to prevent water backflow. This intervention is important because a condensate leak does not always appear immediately during diagnosis. It can occur later, on a very humid day or after several hours of continuous cooling.
Sensor and device behavior check
Our technicians also observed the unit’s behavior at startup and during operation. A temperature sensor that poorly reads ambient air can cause too-short cycles, insufficient cooling, or poorly adapted ventilation. On older devices, sensors and connections can become less accurate over time.
In this case, the behavior was consistent with a dirty machine rather than a major electronic failure. The control responded, the fan worked, and the device followed the requested modes. There was therefore no immediate reason to replace the electronic board or remote control.
Performance test after intervention
After cleaning, drain check, and basic controls, we restarted the device to measure airflow improvement and operational stability. The result was positive: air circulated better, the unit responded faster, and the client could notice a real difference in room comfort.
We also explained that, given the age of the Airwell wall-mounted heat pump, the repair allowed recovery of much of the performance but that the client should remain attentive to future signs: sudden loss of cooling, water leak, intermittent shutdown, persistent odor, motor noise, or error code. A well-done repair can extend a device’s life but does not turn an old machine into a new system.
Why not replace the heat pump immediately?
When a wall unit is aging, many clients think replacement is the only solution. This is not always true. In this case, the main components still seemed capable of functioning. The problem was mainly accumulated maintenance and reduced airflow. A well-targeted intervention was therefore justified.
However, we also took the time to explain the limits. If the machine were to develop a compressor failure, refrigerant leak, defective electronic board, or an unavailable part, replacement would probably become more logical. Some older units use technologies or refrigerants that are no longer as advantageous to maintain. That is why AirGreen’s role is to offer an honest recommendation: repair when reasonable, replace when repair becomes costly or uncertain.
Mistakes to avoid with an old wall-mounted heat pump
On a wall unit like this, several simple actions can prevent repeated service calls.
The first is not to wait until airflow becomes very low before cleaning the filters. A dirty filter forces the device to work longer and can cause secondary problems. The second is not to ignore a small water leak. Even a few drops can indicate a partially blocked drain. The third is to avoid aggressive cleaning with unsuitable products. Some foams, sprays, or rigid tools can damage fins, plastics, or electrical components.
It is also important not to completely close the room or block the air intake. A wall-mounted heat pump must be able to draw ambient air properly to maintain a stable temperature. When installed near the ceiling, as in this project in Chomedey, the space around the unit becomes even more important.
A repair that restores comfort and reassures the client
At the end of the intervention, the client had a cleaner, more stable, and more efficient machine. The room’s comfort was improved without immediate equipment replacement. The service call also clarified the actual condition of the heat pump: it was not new, but it could still operate adequately with proper maintenance and reasonable monitoring.
This is precisely what we aim to achieve during a residential HVAC repair: make the right diagnosis, intervene effectively, explain observations, and allow the client to make an informed decision. Whether in Chomedey, elsewhere in Laval, in Montreal, Longueuil, on the North Shore or the South Shore, AirGreen works on wall systems of different generations, including older heat pumps that require a careful and technical approach.
AirGreen expertise for HVAC service calls in Laval
This project demonstrates the importance of a complete diagnosis on a wall-mounted heat pump that seems to work but whose performance is declining. An HVAC failure is not always dramatic. Sometimes it manifests as a gradual loss of comfort, less cold air, longer operation, poorly controlled humidity, or increased electricity consumption without satisfactory results.
Our team knows how to recognize these signs and intervene methodically. We analyze the machine as a whole: filtration, ventilation, condensate drainage, heat exchange, electronic behavior, accessibility, equipment age, and economic relevance of the repair. This global vision helps avoid unnecessary replacements and incomplete repairs.
For this repair of an Airwell wall-mounted heat pump in Chomedey, the intervention restored the device’s efficiency, prevented a potential drain-related leak, and extended the machine’s use under better conditions. It is a concrete solution, adapted to the field, and true to our way of working at AirGreen: precise, transparent, and sustainable HVAC service.