A wall unit that was cooling less effectively and beginning to show signs of dirt buildup
During this service call in Montreal, our AirGreen team was called to work on a KeepRite wall-mounted heat pump installed high up, near the ceiling, in a residential room where thermal comfort had become irregular. The client noticed a drop in cooling performance, weaker airflow than before, and a persistent feeling of humidity in the room, even when the device had been running for several minutes.
At first glance, the indoor unit seemed to be in good general condition: intact casing, no major signs of physical damage, no visible cracks on the front. However, as is often the case with wall systems installed for several years, significant signs are not always visible from a distance. A device can look clean on the outside while having a partially clogged turbine, evaporator, or condensate drain inside.
In this type of HVAC intervention, our priority is to proceed methodically: observe the symptoms, validate the operating parameters, open the unit, inspect the internal components, then fix the real cause of the problem instead of just restarting or doing a superficial cleaning.
Initial diagnosis of the wall-mounted heat pump
As soon as we arrived, we started by talking with the client to understand the device's history. The most useful information in a service call is never limited to "it no longer works." We try to find out how long the problem has been present, if the performance varies with the outside temperature, if the device makes more noise than before, if any odor is noticeable, if water sometimes leaks from the indoor unit, and if the filters are cleaned regularly.
In this specific case, the symptoms pointed to a combined problem of internal maintenance and condensate drainage. The wall-mounted heat pump was still producing cold air, but not as efficiently. The fan seemed to be running, but the airflow was weakened. The room was harder to reach the requested temperature, which forced the device to run longer.
We therefore carried out the following checks:
- Visual inspection of the KeepRite indoor unit.
- Checking washable filters.
- Observation of the ventilation fan.
- Inspection of the evaporator.
- Checking the slope and drainage flow.
- Function test in cooling mode.
- Checking the airflow at the outlet.
- Observation of signs of abnormal moisture or condensation.
A ceiling-near installation that requires special attention
The indoor unit was installed very close to the ceiling, a common setup in residences in Montreal, Laval, Longueuil, on the North Shore and the South Shore. This positioning can be perfectly acceptable when clearances are respected, but it sometimes makes maintenance more delicate. Access to the top and sides of the device is more limited, which can complicate fully opening the casing or deep cleaning.
In this type of setup, dust accumulation on top of the unit can also be more significant, especially when the heat pump operates for several months a year. Dust is drawn in through the upper air intake, passes through the filters, and gradually accumulates on the evaporator and fan if maintenance is not performed regularly.
A clean filter does not necessarily guarantee a clean unit. Microparticles, light kitchen grease, textile fibers, pet hair, and moisture deposits can form a sticky layer inside the device. Over time, this layer reduces airflow, increases internal humidity, and creates an environment conducive to odors and condensate blockages.
What opening the unit revealed
After securing the work area and protecting the surrounding surfaces, we opened the indoor unit to inspect the internal components. The filters were present and relatively accessible, but the interior showed clear signs of dirt buildup.
The turbine, located behind the air outlet flaps, had a buildup of compacted dust. This type of dirt is particularly problematic because it disrupts air rotation. Even if the fan motor works properly, the turbine can no longer project air as effectively when its blades are loaded with dirt.
The evaporator also showed partial buildup. In a wall-mounted heat pump, the evaporator must allow air to pass freely through its fins. When these fins are dirty, heat exchange is reduced. The result: the device works longer, consumes more energy, cools less effectively, and may produce more condensation.
We also paid special attention to the condensate tray and drain. In air conditioning, air moisture condenses on the evaporator, falls into the tray, and must be drained outside or to a designated drain. If this passage is partially blocked, water can stagnate inside the indoor unit, create odors, promote the growth of organic residues, or potentially cause a leak.
Technical cleaning, drainage correction, and performance restoration
Our intervention involved targeted internal cleaning and restoring proper condensate drainage. Unlike simple filter cleaning, this work requires a more comprehensive approach, as the goal is to address areas that directly affect the performance and reliability of the KeepRite wall-mounted heat pump.
Cleaning of the turbine and evaporator
We first cleaned the filters, then proceeded to clean the turbine. This step requires patience and the right tools, as deposits can be deeply embedded between the blades. A dirty turbine can cause several symptoms:
- Reduced airflow.
- Uneven cooling.
- More noticeable fan noise.
- Light vibrations.
- Odors at startup.
- Prolonged operation of the device.
- Persistent feeling of humidity.
We then carefully cleaned the evaporator to promote better heat exchange. The fins must remain clear to allow air to circulate properly. Poor air circulation can mimic a refrigerant, compressor, or electronic board problem, while the real cause is sometimes simply a lack of internal maintenance.
This distinction is important. At AirGreen, we avoid quick diagnoses that lead to unnecessary replacements. An effective HVAC repair starts with identifying the exact cause. In many cases, a unit considered “worn out” can regain very acceptable performance after professional cleaning and full reconditioning.
Condensate drain inspection
The drain was then tested. We checked the flow to ensure that water was leaving the condensate tray correctly. Partial blockage can be caused by damp dust, sticky deposits, insects, insufficient slope, or a poorly positioned pipe.
In this case, the drainage was not completely blocked but was not optimal. We cleared the passage, cleaned the accessible tray, and confirmed that the water was draining properly. This step is essential because a heat pump that cools well but does not drain water properly can quickly cause damage to the wall, floor, or furniture beneath the unit.
A common mistake is to wait for a major leak to appear before calling a specialist. However, early warning signs often exist: damp smell, water noise, droplets under the unit, marks on the wall, reduced airflow, or intermittent shutdown. The sooner the intervention, the simpler the repair and the lower the risk of damage.
Operation tests after service
Once the cleaning and drainage correction were completed, we restarted the wall-mounted heat pump to validate its behavior. The airflow was more stable, the air output more consistent, and the unit operated with less strain. We observed the unit’s behavior in cooling mode to confirm that condensate drainage was functioning normally.
We also checked that the louvers responded correctly, that the fan changed speed according to the controls, and that the unit did not produce any abnormal noise after reassembly. The customer noticed an immediate improvement in airflow, which is often the first visible sign after a successful internal cleaning.
Why this type of problem often recurs with wall-mounted heat pumps
Wall-mounted heat pumps are widely used in Greater Montreal because they are efficient, compact, and suitable for condos, houses, multiplexes, light commercial spaces, and rental units. They often serve both heating and cooling purposes, meaning they can operate almost year-round.
This prolonged use increases the importance of maintenance. A device that only runs a few weeks a year does not clog at the same rate as a unit used to heat in spring, cool all summer, dehumidify in fall, and provide supplemental heating in winter.
Factors that accelerate clogging include:
- Presence of pets.
- Open-concept kitchen.
- Smoke, candles, or incense.
- High humidity.
- Recent renovation work.
- Filters cleaned too rarely.
- Intensive use in cooling mode.
- Unit installed near the ceiling with accumulated dust circulation.
Mistakes to avoid before a service call
Before calling for a wall-mounted heat pump repair, some simple actions can be helpful, but others can worsen the situation. We recommend cleaning the filters regularly, checking if the remote control is properly set, ensuring the louvers are open, and noting the observed symptoms.
However, it is important to avoid disassembling the unit without experience, inserting objects into the turbine, pouring chemicals into the condensate tray, forcing motorized louvers, or covering a leak with a towel for several days. An indoor water leak is never normal. It must be evaluated quickly.
The importance of a complete diagnosis rather than a simple guess
In the HVAC field, several symptoms can have similar causes. Low efficiency can come from lack of maintenance, refrigerant leaks, a weakened fan motor, a faulty sensor, a problematic electronic board, or poor installation. A water leak can be related to the drain, slope, evaporator freezing, a clogged filter, or abnormal operating pressure.
That is why our approach is always to validate the most likely elements before concluding. In this case, the internal condition of the unit and the imperfect condensate drainage explained the reported symptoms well. Technical cleaning and restoring the drainage improved performance without unnecessary parts replacement.
A service adapted to the realities of Montreal homes
Homes in Montreal often present particular challenges: old walls, ceilings that are lower or higher depending on the building, installations at height, restricted access, drains sometimes directed toward less visible outlets, units installed above furniture or in highly decorated rooms. A clean and safe intervention therefore requires preparation.
During this call, we took care to protect the area under the unit, work cleanly around the wall elements, and restore the space to order after the service. This attention to detail is an integral part of good HVAC service, especially when the unit is installed in an occupied and furnished living space.
Final result: improved comfort and better-protected equipment
At the end of the service, the KeepRite wall-mounted heat pump was operating more healthily. Airflow was improved, condensate drainage was restored, and the unit could once again provide more effective cooling. The client also received simple recommendations to reduce the risk of recurrence: periodic filter cleaning, monitoring for odors, watching for signs of moisture, and scheduling professional maintenance when airflow begins to decrease.
At AirGreen, we work on wall-mounted heat pumps, wall air conditioners, multi-zone systems, central heat pumps, and other HVAC equipment in Greater Montreal, including Montreal, Laval, Longueuil, the North Shore, and the South Shore. Every service call is handled with a simple approach: understand the problem, make an accurate diagnosis, perform the right fix, and leave the client with a more reliable, cleaner, and better-performing system.