A wall heat pump installed in a living room, still functional but weakened by an airflow and drainage problem
In a residence in Charlemagne, our AirGreen team was called for a wall heat pump repair installed in a living room, above a sofa and near a large window. The indoor unit, from the Leto series visible on the front, still responded to the remote control and seemed to function normally at first glance. However, the customer had noticed for some time a loss of performance, weaker air output, and an unusual feeling of humidity around the device on hot days.
The installation was typical of a residential wall system: a compact indoor unit, installed high to distribute air in a living room, connected to an outdoor unit by refrigerant lines, a communication cable, and a condensate drainage system. This type of wall heat pump is very common in Charlemagne, on the North Shore, as well as in Montreal, Laval, Longueuil, and on the South Shore, because it allows efficient cooling and heating without ductwork.
In this specific case, the problem did not present as a complete breakdown. The device displayed a setpoint, the vents opened, the fan ran, but the comfort in the room was no longer consistent. This is exactly the kind of service call where a thorough HVAC diagnosis is essential: a machine that is still running can still be losing efficiency due to internal clogging, a partially blocked drain, an inaccurate sensor, or weakened ventilation.
Symptoms observed by the customer
The customer reported several signs that appeared mainly during extended use periods:
- a lower airflow than before;
- slower air conditioning in the living room;
- a sensation of humid air near the unit;
- a slight irregular noise when the flaps were open;
- a fear of water leakage near the wall;
- a feeling that the device had to run longer to reach the requested temperature.
These symptoms are common on wall units installed in living rooms. In a living room, the device often runs several hours a day, sometimes with windows heavily exposed to the sun, dust circulation, textiles, cushions, curtains, scent diffusers, or pets. All this can contribute to dust buildup in the filters, turbine, and evaporator.
Inspection of the immediate environment
Before opening the unit, we inspected its location. The heat pump was installed high on the wall, near the ceiling, above a space occupied by a sofa, a side table, and decorative objects. This setup requires careful work: furniture must be protected, any splashing during drainage tests avoided, and work done precisely to avoid marking the wall.
The proximity of a large window is also important. Windows let in heat, light, and fine dust, especially when blinds are open or the room is heavily exposed. A wall-mounted heat pump placed in this area can be very effective, but it must stay clean to maintain good heat exchange.
Opening the front panel and checking the filters
The first technical step was the controlled opening of the front panel. The filters were removed and inspected. They were loaded with fine dust but not completely blocked. However, this accumulation was enough to reduce the volume of air drawn in by the device.
On a wall-mounted heat pump, the filters play a direct role in performance. When air flows poorly through the filters, the evaporator receives less air, the blowing temperature becomes less stable, and the unit has to work longer. The customer may then believe the machine is low on refrigerant, when the problem actually starts with an air restriction.
Inspection of the inner turbine
After the filters, we examined the inner turbine. This is often where the real cause of airflow loss is found. The turbine, also called a tangential fan, is located behind the outlet flaps. Even when the filters are cleaned regularly, sticky dust can accumulate on the turbine blades.
In this intervention in Charlemagne, the turbine showed visible buildup. This type of clogging causes several effects:
- reduced volume of blown air;
- irregular rotation noise;
- less even distribution in the room;
- musty smell at startup;
- feeling that the unit cools less;
- higher risk of internal condensation.
The turbine wasn’t stuck, but it had lost efficiency. We therefore performed a technical cleaning of the accessible parts, working carefully to avoid unbalancing the fan.
Evaporator inspection
The evaporator, located behind the filters, showed a light to moderate dust buildup. In a wall system, this exchanger is crucial: it allows indoor air to be cooled or heated depending on the mode used. If the fins are dirty, heat exchange becomes less efficient.
We cleaned the accessible areas of the evaporator using a method suited to the unit’s condition. It’s important to avoid bending the fins, as this would further reduce airflow. A good HVAC repair isn’t just about quickly cleaning the visible surface but restoring the actual airflow through the unit.
Testing the condensate tray and drain
Since the client feared a leak, we tested the drainage. In cooling mode, a wall-mounted heat pump naturally produces water. This water must fall into the condensate tray, then drain outside or to a designated drainage point.
The test revealed slowed drainage. Water was still passing through, but not as quickly as it should. This type of situation often causes intermittent leaks: the unit doesn’t leak every day, but when humidity rises or the machine runs longer, the tray can fill faster than the drain empties.
We cleared the drain, cleaned the condensate tray, and confirmed the flow after the intervention. This step was essential to prevent water from overflowing onto the wall or furniture beneath the unit.
Targeted performance restoration to avoid premature replacement
After cleaning the filters, turbine, evaporator, and drainage, we restarted the unit to validate its performance. The heat pump responded correctly to the remote control, the louvers resumed a more stable movement, and the airflow at the outlet was noticeably more consistent.
Blowing temperature control
We measured the difference between the return air and the supply air. After a few minutes of operation, the temperature difference was consistent with a functioning wall unit. The main problem was therefore not a complete refrigerant circuit failure, but rather a loss of performance caused by dirt buildup and slowed drainage.
This diagnosis helped avoid an unnecessary replacement recommendation. In many service calls in Montreal, Laval, Longueuil, on the North Shore and the South Shore, we see wall systems replaced too quickly when a technical cleaning and drain correction could have extended their lifespan.
Result achieved after the intervention
At the end of the service call, the Leto wall-mounted heat pump operated more steadily. The customer noticed improved airflow and a better feeling of freshness in the living room. Drainage was restored, and the risk of condensate tray overflow was reduced.
Main results:
- Improved airflow;
- Filters cleaned;
- Indoor fan cleared;
- Evaporator inspected and cleaned;
- Drain unclogged;
- Condensate drainage verified;
- Reduced ventilation noise;
- Indoor comfort restored.
Mistakes to avoid with a wall-mounted heat pump in a living room
A common error is cleaning only the filters and believing the maintenance is complete. Filters are important, but the fan, evaporator, and drain must also be checked periodically.
Another mistake is placing objects directly under the unit without monitoring signs of moisture. In a living room, a small leak can damage a sofa, floor, table, or wall before the customer even notices.
It is also important not to ignore subtle noises. A rubbing or irregular ventilation noise can indicate a dirty fan or a stuck louver. The earlier the intervention, the easier it is to prevent a more costly breakdown.
Our AirGreen approach for this type of repair
At AirGreen, every service call for a wall-mounted heat pump begins with a thorough assessment of the situation: unit location, symptoms, daily usage, access, condition of filters, fan, evaporator, louvers, drain, and the device's behavior after restarting.
This method allows finding the real cause of the problem. In this intervention in Charlemagne, the machine was not dead; it was simply suffocated by internal buildup and hindered by slow drainage. A targeted intervention restored its performance without immediate replacement.
Maintenance tips after our visit
We recommended the client clean the filters regularly during periods of heavy use, especially in summer. More thorough maintenance should also be scheduled at regular intervals to clean the turbine and check the drain.
A well-maintained wall heat pump offers better comfort, consumes less energy, and reduces the risk of water leaks. For residences in Charlemagne, Montreal, Laval, Longueuil, the North Shore, and the South Shore, this maintenance is especially useful before hot periods, when units operate several hours a day.
HVAC repair service in Charlemagne and Greater Montreal
AirGreen provides wall heat pump repair, water leak issues, clogged drains, air flow losses, ventilation noises, stuck louvers, electrical failures, performance losses, and HVAC maintenance in Charlemagne, Montreal, Laval, Longueuil, on the North Shore and the South Shore.
This intervention shows that a wall unit that seems to be working may still require a real repair. Thanks to a precise diagnosis, technical cleaning, and drainage correction, the wall heat pump regained more reliable performance and the client regained better comfort in their living space.