An indoor water leak that hid a drainage and HVAC maintenance problem
In Longueuil, our AirGreen team was called for a Gree wall heat pump repair installed in a residential room where the indoor unit was positioned high on a wall, close to the ceiling. At first glance, the device seemed clean and well integrated into the space, with its white casing, lower flap, and the Gree logo visible in the center of the front. Yet, the customer had reported a very concrete problem: water was starting to appear under the unit, accompanied by less powerful airflow and slower cooling than before.
This type of service call is common in Longueuil, but also in Montreal, Laval, on the North Shore and the South Shore. A wall heat pump may seem to operate normally because it starts, blows air, and responds to the remote control. However, when a condensate drain is partially blocked, when the fan wheel is dirty, or when the evaporator begins to retain too much moisture, symptoms gradually appear: water drops, musty smell, decreased performance, duller noise, longer cycles.
In this specific case, the intervention involved a Gree wall unit of the mini-split type, used for air conditioning and heating depending on the season. The exact BTU capacity had to be confirmed by the device’s nameplate, but the visual format corresponded to a standard residential wall heat pump, typically installed in a living area, living room, bedroom, or medium-sized dwelling.
Symptoms reported by the customer
The customer explained to us that the device had started producing small drops under the lower part of the casing. At first, the phenomenon was intermittent. Then, on more humid days, the water became more visible. At the same time, the air seemed less fresh and less direct than before. The heat pump was still working, but it seemed to have to work longer to achieve the same comfort.
The main symptoms were as follows:
- water visible under the indoor unit;
- reduced airflow;
- slower cooling;
- slight musty smell at startup;
- less distinct fan noise;
- possible condensation buildup in the indoor pan.
These signs often point the diagnosis toward the drainage circuit, but at AirGreen, we never stop at the first assumption. A water leak can come from a clogged drain, a cracked pan, improper slope, an unevenly leveled device, a very dirty coil, incorrect refrigerant pressure, or insufficient insulation around the refrigerant lines.
Inspection of the Gree indoor unit
Our technician began with a complete visual inspection of the wall unit. The front panel was intact, the lower flap worked, and no major damage was visible on the casing. However, the presence of moisture near the lower part indicated that water was not draining properly.
We carefully opened the device to check the accessible internal components:
- filters;
- evaporator;
- condensate pan;
- drain outlet;
- fan wheel;
- flaps;
- temperature sensor;
- general condition of the indoor unit casing.
The filters showed dust buildup, without being completely clogged. However, the evaporator and drainage area showed more advanced signs of dirt accumulation. When a wall-mounted heat pump operates in cooling mode, the air’s humidity condenses on the evaporator. This water must then naturally flow to the pan, then to the drain. If dust, biofilms, or deposits accumulate, water flow becomes more difficult.
Condensate drain diagnosis
The drain check confirmed a partial blockage. The water did not flow at a steady rate. It stagnated in the pan before slowly draining, which explained the visible drops under the unit during periods of high humidity.
A partial blockage is sometimes more deceptive than a complete clog. When the drain is fully blocked, the problem becomes apparent quickly. But when it is only partially blocked, the system can operate properly for several hours, then leak when condensation becomes more abundant. This often happens in summer in Longueuil, when indoor humidity is high and the heat pump runs longer.
We proceeded to clear the drain and perform a controlled rinse of the drainage circuit. The goal was to restore free passage without damaging the tray, fittings, or existing duct.
Targeted cleaning of the evaporator and fan wheel
The leak was not the only problem. The weakened airflow also indicated that the unit needed internal cleaning. On a wall-mounted heat pump, the fan wheel can accumulate fine dust, especially when filters are not cleaned regularly or when the unit runs for long hours in cooling mode.
A dirty fan wheel can cause:
- a decrease in airflow;
- a heavier noise;
- less uniform air distribution;
- a less effective cooling sensation;
- an increased accumulation of moisture on the evaporator.
We performed targeted cleaning of accessible areas, paying special attention to the evaporator, condensate tray, and ventilation fan. This step improved air circulation and reduced the amount of moisture retained inside the unit.
Level and drainage check
A wall-mounted heat pump must be slightly tilted to allow water to flow correctly toward the drain outlet. Even an installation that has worked well for several years can eventually develop a problem if the support shifts slightly, the wall moves, or the drain shifts within the duct.
We then checked the unit’s alignment and the direction of the drainage. The overall level was acceptable, but the drain required better clearance and a full validation after cleaning. Once the blockage was removed, we poured a small amount of water into the tray to confirm that the drainage was properly flowing outside.
The result was clear: water was now leaving the unit without backing up.
A repair that restored comfort and prevented a more serious breakdown
After cleaning, clearing the drain, and internal checks, we restarted the Gree wall-mounted heat pump. The unit was tested in cooling mode to replicate the conditions causing the leak. We observed the behavior of the evaporator, the airflow, condensation production, and drainage.
The system returned to more stable operation. Airflow was better, condensation drained properly, and no drops appeared under the unit during tests. The client also noticed that the blown air was more consistent and that the unit seemed to operate with less effort.
Why a water leak should never be ignored
A water leak from a wall-mounted heat pump may seem minor at first, but it can quickly cause damage to the wall, paint, floor, or furniture. In some cases, moisture can also cause unpleasant odors and degrade air quality.
A partially blocked drain can also cause water to accumulate inside the unit. This stagnant moisture promotes dirt buildup on the evaporator and fan wheel, which further reduces system performance. It’s a cycle that worsens over time: less air, more moisture, more dirt, and higher risk of leaks.
Mistakes to avoid with a Gree wall-mounted heat pump
During our service calls in Montreal, Laval, Longueuil, on the North Shore and the South Shore, we often see the same mistakes:
- waiting for the leak to become significant before calling;
- cleaning only the filters without checking inside;
- using inappropriate products in the drain;
- forcing the louvers by hand;
- blocking the air outlet with curtains or furniture;
- neglecting maintenance of the fan wheel;
- believing that a musty smell is normal;
- ignoring a drop in airflow.
Cleaning the filters is important, but it does not replace internal maintenance when the evaporator, tray, or turbine are dirty. A Gree wall-mounted heat pump can offer excellent performance, but it must be able to drain water and circulate air properly.
An AirGreen approach based on a complete diagnosis
At AirGreen, we don’t just unclog a drain without understanding why the problem occurred. During this service in Longueuil, we checked the entire system: filters, evaporator, tray, drain, fan wheel, drainage, and operation after repair.
This method helps avoid temporary repairs. A drain can be quickly cleared, but if the fan is very dirty or the evaporator retains too much moisture, the problem is likely to return. Our goal is always to provide a durable solution, adapted to the actual condition of the device.
Advice given to the client after the intervention
At the end of the service call, we advised the client to monitor certain signs in the coming weeks:
- appearance of new drops under the unit;
- musty smell at startup;
- decreasing air flow;
- unusual ventilation noise;
- slower cooling;
- visible water accumulation near the lower flap.
We also recommended regular filter cleaning and more thorough maintenance when the unit is frequently used for cooling. In homes with high humidity, preventive maintenance can make a significant difference in system performance and lifespan.
Reliable HVAC service for wall-mounted heat pumps in Longueuil
This repair of a Gree wall-mounted heat pump in Longueuil demonstrates the importance of an accurate diagnosis even when the problem seems simple. An indoor water leak can result from a blocked drain, but it can also reveal insufficient maintenance, reduced air flow, or moisture buildup in the unit.
AirGreen regularly handles the repair of wall-mounted heat pumps, wall air conditioners, MultiZone heat pumps, central heat pumps, electric furnaces, indoor systems, PTAC / VTAC, and HVAC accessories. Our team serves Longueuil, Montreal, Laval, the North Shore, and the South Shore with a technical, clear, and tailored approach for each installation.
In this case, the solution restored the flow, improved the air flow rate, reduced the risk of leaks, and provided the client with a cleaner, more stable, and more efficient system.