A discreet indoor leak that revealed a drainage, maintenance, and airflow problem
In Beaconsfield, our AirGreen team was called for a LG wall-mounted heat pump repair installed in a residential room where the customer had noticed a problem that seemed minor at first: a few drops of water under the indoor unit, a musty smell at startup, then a gradual drop in cooling performance. The heat pump was still working, air was still coming out of the unit, but comfort was no longer as stable. In this type of situation, especially with a wall-mounted heat pump installed near the ceiling and in a corner of the room, a small anomaly can quickly become a sign of a deeper problem.
The unit seen on site was a LG wall-mounted heat pump, residential size, connected to an outdoor condenser by a refrigerant line and a condensation drain. Although the exact model and BTU number were not readable from the indoor photo, the setup matched a typical wall unit used to cool and heat a specific area of the house. This type of system is very common in Beaconsfield, as well as in Montreal, Laval, Longueuil, on the North Shore and the South Shore, where many homeowners choose wall-mounted heat pumps for their efficiency, discretion, and ability to improve comfort without changing the entire duct network.
Symptoms observed by the customer
The customer contacted us because the LG indoor unit showed three worrying signs:
- Water occasionally appeared under the wall-mounted heat pump;
- A musty smell was noticeable at startup;
- The cooling was slower than before, especially on hot days.
These symptoms can have several causes. An internal water leak can come from a blocked drain, insufficient slope, dust buildup in the condensation tray, a dirty internal coil, a clogged filter, poor external drainage, or even the beginning of freezing on the evaporator. A musty odor often indicates that water remains too long inside the unit or in the drain, creating an environment favorable to organic deposits and bacteria.
At AirGreen, we avoid treating a water leak as just a simple superficial cleaning. A leaking wall-mounted heat pump often signals an imbalance in condensate drainage. Therefore, the entire system must be inspected: filters, coil, tray, drain, slope, external outlet, ventilation speed, and machine behavior in cooling mode.
First inspection: unit position, access, and internal condition
The LG wall-mounted heat pump was installed high on the wall, very close to the ceiling, in a corner of the room. This position is common, but it makes maintenance more delicate. When the space above the unit is limited, access to the filters, above the casing, and certain internal sections can become more difficult. A unit installed too close to the ceiling can also be more prone to dust buildup in the air intake area, especially if regular maintenance is not performed.
Our technicians started by checking the external condition of the unit, the visible level, the opening of the motorized flap, the cleanliness of the filters, and signs of leaks around the casing. Even when a leak is not visible at the time of the call, it is possible to spot traces: stuck dust, small moisture marks, odor in the airflow, or stagnant water in the tray.
The visual inspection showed that the system needed more thorough technical maintenance. The filters were loaded with fine dust, and the inside of the unit showed signs of buildup in the coil and condensation tray area. This buildup did not completely prevent the machine from working, but it hindered air circulation and promoted moisture retention.
Drainage diagnosis: the central point of the intervention
On an LG wall-mounted heat pump, the water produced in cooling mode must be collected in an internal tray, then drained by gravity or pump depending on the installation setup. If the drain is partially blocked, water can accumulate, rise in the tray, and eventually overflow inside.
We tested the drainage by pouring a controlled amount of water into the condensation pan to observe the drainage speed. The water drained, but too slowly. This indicated a partial obstruction rather than a complete blockage. This type of problem is often more deceptive because the system can operate normally for several hours, then leak only when indoor humidity is high or when the heat pump runs for a long time.
The drain was then cleaned using an appropriate method, without applying excessive pressure that could disconnect or crack a hidden section. We cleared accumulated deposits, checked the external outlet, and confirmed that water flowed freely after the intervention.
Cleaning the condensation pan and evaporator
Drainage was only part of the problem. The presence of a musty odor also indicated that the condensation pan and some internal surfaces had retained water and deposits. We therefore carried out a targeted cleaning of the indoor unit, paying special attention to areas that directly affect air quality and water flow.
The cleaned and checked elements included:
- the washable filters;
- the surface of the evaporator coil;
- the condensation pan;
- the accessible sections of the drain;
- the air outlet flap;
- the fan wheel, depending on possible access;
- areas where dust retained moisture.
A dirty coil can reduce heat transfer and cause the surface temperature to be too low. In some cases, this can promote the start of frost, especially if the airflow is reduced. When this frost melts, it can produce more water than the drain pan can normally evacuate, increasing the risk of leaks.
After cleaning, air flowed more freely through the indoor unit. The airflow was more even, and the startup odor had noticeably decreased.
Checking operation in cooling mode
Once the drain was cleaned and the indoor unit restored, we tested the LG wall-mounted heat pump in cooling mode. It is not enough to confirm that the air is cold. A good HVAC diagnosis requires checking the system's behavior during a real cycle.
We observed:
- the speed of the indoor fan;
- the temperature of the return and blown air;
- the behavior of the motorized flap;
- normal condensation formation;
- continuous flow to the drain;
- no drops on the casing;
- the remote control response;
- operating stability after several minutes.
The system returned to much more stable operation. The water produced by the evaporator drained properly, without abnormal accumulation in the tray. The client noticed that the heat pump blew better, the musty smell was controlled, and the leak did not recur during the test.
Why an indoor leak should never be ignored
A small leak under a wall-mounted heat pump may seem minor, but it can quickly cause damage to the wall, paint, floor, or furniture. In a home in Beaconsfield, where many properties have fine interior finishes, a repeated leak can become costly if not treated quickly.
The most common mistakes we observe are the following:
- wipe the water without looking for the cause;
- continue using the device for several days despite the leak;
- clean only the filters thinking the problem is solved;
- pour unsuitable products into the drain;
- disassemble the unit without knowing the configuration;
- ignore the musty smell;
- wait for the heat pump to stop completely.
A water leak is rarely accidental. It almost always indicates that drainage, maintenance, or air circulation are no longer normal.
An AirGreen intervention focused on the cause, not just the symptom
In this case, the solution was not to replace the LG wall-mounted heat pump. The system still had good operating capacity but needed precise intervention: drain cleaning, tray cleaning, evaporator inspection, airflow check, and a full test in cooling mode.
This approach helps avoid premature replacement and extends the machine's lifespan. This is especially important with wall-mounted heat pumps from well-known brands like LG, which can provide good performance for several years when properly maintained.
Our team also explained to the client how to recognize the early signs of a drainage problem:
- odor appearing at startup;
- water noise in the indoor unit;
- drops under the casing;
- less effective cooling;
- persistent humidity in the room;
- unusual shutdown or irregular behavior.
This information helps the client better use their system and call before a small problem turns into a bigger repair.
Comfort restored thanks to a well-targeted wall repair
This LG wall-mounted heat pump repair in Beaconsfield highlights the importance of a thorough diagnosis when a system starts leaking or losing performance. The main issue was a partially clogged drain, worsened by dust and moisture buildup inside the indoor unit. By cleaning critical components and ensuring proper condensate flow, we helped the system operate cleaner, more stable, and more efficiently.
At AirGreen, we work on wall-mounted heat pumps, wall air conditioners, MultiZone systems, central units, and other HVAC equipment in Montreal, Laval, Longueuil, on the North Shore, the South Shore, and throughout the West Island, including Beaconsfield. Every service call is handled with a structured approach: listen to symptoms, inspect the installation, test components, fix the cause, and verify the result.
A repair that protects the machine and the home
The client regained more efficient air conditioning, a cleaner indoor unit, and peace of mind regarding leak risks. This type of intervention is essential to protect not only the wall-mounted heat pump but also the interior surfaces of the home.
An LG wall-mounted heat pump that leaks, smells damp, or cools less effectively should not be left unchecked. With proper technical maintenance and targeted repair, it is often possible to restore comfort without replacing the unit.
Repair of an LG wall-mounted heat pump in Beaconsfield by AirGreen, HVAC service in Montreal, Laval, Longueuil, North Shore, and South Shore for leaks, drainage, and maintenance.
AirGreen repairs an LG wall-mounted heat pump in Beaconsfield: HVAC diagnosis, drain cleaning, fixing an indoor water leak, and restored comfort.