An aging wall unit that blew little air, emitted a damp smell, and no longer stabilized the temperature
In Repentigny, our AirGreen team was called for a wall heat pump repair installed in a main room of a residence. The indoor unit, branded IGLU, showed typical signs of a device that had provided good service for many years but was starting to lose efficiency: yellowed front panel from age, less responsive louvers, visible dust buildup in the air outlets, and irregular operation depending on the cycles.
The client contacted us because the unit no longer provided the expected comfort. In cooling mode, the air seemed less cold and the airflow was weak. In heating mode, the wall heat pump started, but the room took far too long to reach the desired temperature. A musty smell also appeared during the first moments of operation, especially after a period of shutdown. This kind of symptom does not always indicate a major breakdown, but it deserves a full diagnosis, as several causes can overlap.
From the moment we arrived, the visual condition of the indoor unit guided our inspection. The casing showed normal wear for an older device, but the air vents revealed internal dirt buildup. On a wall heat pump, performance depends as much on the outdoor unit as on the indoor unit: if the tangential fan, evaporator, filters, or condensate drain are clogged, the system may seem to be low on refrigerant when the main problem is actually in the air circulation.
An old IGLU wall heat pump, but still recoverable with a good diagnosis
This IGLU wall unit was installed high up, near a corner of the room, as is often the case in houses and condos in Repentigny, Montreal, Laval, Longueuil, the North Shore, and the South Shore. The positioning allowed for good overall air distribution, but the age of the unit and lack of deep maintenance had eventually reduced its efficiency.
The client had already cleaned the visible filters a few times, but without lasting improvement. This is a common situation: cleaning the filters is important, but it is not enough when dirt has accumulated behind the front panel, on the fan wheel, in the condensate pan, or between the evaporator fins. At this stage, the device may continue to operate, but it works harder, consumes more, makes more noise, and distributes air less effectively.
Symptoms observed before the intervention
Before opening the unit, we validated the behavior of the wall-mounted heat pump with the client. The symptoms were precise and consistent:
- low airflow despite high fan speed;
- damp smell at startup;
- unstable room temperature;
- less smooth air vents;
- longer cycles than before;
- slight condensation under the air outlet on humid days;
- duller noise coming from the indoor unit.
These signs indicated a combined problem: air restriction, internal dirt buildup, and possibly a partially blocked condensate drain. A complete electronic failure was less likely, as the device still responded to the remote control and started normally. However, we still included electrical components and sensors in our check, as an older wall-mounted heat pump can show unstable readings without being completely broken.
Opening the unit and inspecting internal components
After securing the device, we removed the filters, opened the front panel, and inspected the interior. The visual diagnosis confirmed that the fan wheel was dirty. An accumulation of dust, grayish deposits, and particles stuck to moisture reduced the fan’s ability to push air properly. Even though the motor was running, the wheel no longer moved the expected volume of air.
The evaporator also had partially blocked areas. The fins were not completely clogged, but dirty enough to reduce heat exchange. When air does not pass well through the coil, the wall-mounted heat pump loses efficiency. In cooling mode, this can cause less cold air, excessive condensation, or even frost. In heating mode, the device may seem to operate without effectively warming the room.
The condensate drain: a detail that can cause major inconveniences
One of the most important points of this intervention concerned the condensate pan and drain. The client had noticed small traces of moisture under the unit, without any major leaks. This detail is often overlooked, but it can indicate a gradual blockage.
We inspected the drainage tray and tested the evacuation. The drain was not completely blocked, but it drained too slowly. A buildup of biofilm, damp dust, and residues had formed in the passage. This partial obstruction explained the odor at startup and the visible condensation on hot, humid days.
On a wall-mounted heat pump, a partially clogged drain can become a real emergency if water backs up into the indoor unit. This can damage the wall, create stains, affect electronic components, or cause persistent odors.
Technical cleaning, restoration, and complete performance verification
Our intervention was not limited to surface cleaning. To restore the performance of this IGLU wall-mounted heat pump, it was necessary to address the root cause: internal buildup, air restriction, and slow condensate drainage.
Thorough cleaning of the indoor unit
We performed a technical cleaning of the indoor unit, protecting the work area and controlling the flow. The goal was to remove deposits without damaging the more fragile components of an older device.
The intervention included:
- Cleaning washable filters;
- Cleaning the front panel and air outlet grilles;
- Cleaning the tangential fan;
- Decontamination of the condensate tray;
- Clearing the drain;
- Careful cleaning of the evaporator;
- Checking motorized flaps;
- Inspection of accessible connections;
- Function test after reassembly.
After cleaning the ventilation wheel, the difference in airflow was clear. The fan produced a more consistent, less muffled airflow, and the air was better distributed in the room. The dull noise decreased because the buildup on the wheel created a slight imbalance that affected the casing.
Checking probes and response to the remote control
We then checked the temperature reading and the unit's response to controls. A wall-mounted heat pump receiving incorrect temperature information can stop too early, run too long, or cause discomfort. In this case, the ambient temperature probe was dirty and poorly positioned in its internal holder. It was not completely defective, but its reading could be influenced by dust buildup and poor air circulation around the front panel.
We cleaned the reading area, correctly repositioned the probe, and validated the device's response in air conditioning and ventilation mode. The system responded better after the intervention. No major electronic replacement was required, which kept the repair reasonable for the client.
Refrigerant circuit check: don’t confuse low airflow with refrigerant shortage
A performance drop is often interpreted as a refrigerant shortage. However, in this specific case, the signs first pointed to an airflow problem. After cleaning, we observed the blowing temperature and unit behavior. The improved airflow confirmed that the device could still produce satisfactory heat exchange when air circulated properly.
We also inspected indirect signs of a refrigerant problem: abnormal frost, short starts, unusual noise from the outdoor compressor, rapid line temperature drop, or inconsistent operation. Nothing justified blindly adding refrigerant. This step is important because a poor intervention on the refrigerant circuit can be costly and not solve the problem if the main cause is simply internal dirt buildup.
Result after repair: improved airflow and restored comfort
After reassembly, we tested the IGLU wall-mounted heat pump in several modes. The airflow was stronger, distribution more even, and the moisture smell had greatly diminished. The drain was evacuating properly, the louvers responded better, and the blowing temperature was more stable.
The customer immediately noticed that the device no longer seemed “choked.” This is often the best indicator after this type of repair: the machine resumes a more natural operation, without strain, excessive noise, or unnecessarily long cycles.
Mistakes to avoid with an old wall-mounted heat pump
This intervention in Repentigny illustrates several common mistakes we observe on older wall units.
Cleaning only the filters
Filters are the first barrier, but they don’t protect everything. Over time, dust still passes through to the wheel, evaporator, and condensate tray.
Ignoring moisture odors
A smell at startup can indicate a dirty tray, a slow drain, organic buildup, or stagnant moisture. The longer you wait, the harder the cleaning becomes.
Forcing the louvers by hand
The motorized louvers of a wall unit can be fragile, especially on an older device. Forcing them can break a gear or a small motor.
Adding refrigerant without diagnosis
A dirty wall-mounted heat pump can mimic the symptoms of a refrigerant shortage. A complete HVAC diagnosis avoids unnecessary expenses.
Advice given to the customer to extend the device's lifespan
We recommended regular maintenance, especially before periods of heavy use. For a wall-mounted heat pump installed for several years, a deep cleaning can make a big difference in comfort, noise, and consumption.
We also advised the customer to watch for three specific signs:
- return of a damp smell;
- rapid decrease in airflow;
- water appearing under the indoor unit.
If any of these symptoms return, it is better to act quickly. A small drain blockage can be easily fixed at first but cause wall damage if ignored.
A useful repair, without premature replacement
In this project, the customer wondered if the heat pump needed to be replaced. After diagnosis, our conclusion was clear: the device was old, but the main failure did not justify immediate replacement. The machine could still operate properly after a technical cleaning and drainage restoration.
At AirGreen, we favor this approach: repair when repair makes sense, explain the device's limits, and prepare the customer for a future replacement only when it becomes necessary. A well-done HVAC repair can extend the life of a wall system and restore comfort without imposing a major expense.
AirGreen for wall-mounted heat pump repair in Repentigny and Greater Montreal
Our team works on wall-mounted heat pumps, wall air conditioners, multi-zone systems, and central installations throughout the region: Montreal, Laval, Longueuil, North Shore, South Shore, and nearby areas like Repentigny. Every service call is handled with the same rigor: understanding the symptoms, inspecting the device, identifying the real cause, and restoring the system in a durable way.
This repair of an IGLU wall-mounted heat pump shows that an old device can often regain appreciable performance when the intervention is precise. The customer's comfort was restored, the air circulates better, the odor was treated at the source, and the device can continue to serve with proper maintenance.