A meticulous HVAC intervention on two wall units installed at height
At this residential property in Montreal, our AirGreen team was called for a performance and noise issue on a system composed of two outdoor units of Goodman wall-mounted heat pumps, installed side by side on wall mounts. Upon arrival, the setup caught attention: both condensers were mounted high on a side wall, with refrigerant lines protected by white covers, exposed electrical conduits, and sturdy metal supports anchored into the exterior cladding.
This type of installation is common in residential areas of Montreal, Laval, Longueuil, the North Shore, and the South Shore, especially when floor space is limited or when the client wants to free up the yard, protect the units from snow accumulation, or avoid constraints related to a slab on the ground. However, a high installation requires special attention during a service call: safe access, vibration checks, anchor inspection, condition of supports, drainage, line slope, clearance around units, and quality of electrical connections.
In this specific case, the client contacted us because one of the two wall-mounted heat pumps was making an unusual noise at startup, while the other seemed less efficient than before in heating mode. The indoor comfort had become uneven: some rooms reached the desired temperature quickly, while others remained cooler even after a long operating period. The client also noticed slight traces of moisture near the duct paths, indicating that a condensate or insulation problem might be the cause.
Complete diagnosis: noise, drainage, performance, and safety of the installation
Before replacing a part or concluding too quickly that there is a major failure, we always perform a complete system analysis. An effective HVAC repair relies on an accurate diagnosis. In the case of a wall-mounted heat pump, several symptoms can seem similar: a lack of heating can come from a clogged filter, a blocked outdoor coil, a weakened fan, a refrigerant shortage, a faulty sensor, a communication problem between the indoor and outdoor units, or poor drainage causing moisture and ice.
Visual inspection of the outdoor units
The first step was to inspect the two Goodman outdoor units. Their positioning on wall mounts provided good clearance from the ground, which is an important advantage in winter, especially in Montreal where snow and ice buildup can hinder air circulation around a heat pump. However, wall installation can amplify certain vibrations if the supports are no longer perfectly tightened or if the dampers are worn out.
Our technicians checked:
- the condition of metal supports;
- the tightening of anchor bolts;
- the presence of vibration transmitted to the wall;
- the clearance around the ventilation grilles;
- the cleanliness of the outdoor coils;
- the condition of refrigerant lines;
- the protection of electrical connections;
- the path of drains and ducts;
- signs of moisture, frost, or corrosion.
We quickly found that the noise mainly came from a vibration transmitted by one of the supports, combined with a slight misalignment of the outdoor fan at startup. The compressor was running, but the vibration became noticeable in the wall structure, which explained why the customer heard it more inside, especially in the morning when the heat pump restarted after a temperature drop.
Electrical check and communication between components
A Goodman wall-mounted heat pump relies on stable communication between the indoor unit and the outdoor unit. When a system becomes intermittent, electrical connections, terminal blocks, circuit breakers, disconnect boxes, and communication cables should never be overlooked. In this case, the outdoor electrical boxes were accessible but exposed to the typical weather variations of the Montreal area.
We carried out a complete check:
- power supply voltage;
- cable continuity;
- condition of terminal blocks;
- presence of oxidation;
- tightening of connections;
- unit response during startup cycles;
- available diagnostic codes;
- behavior of the outdoor fan;
- heat call from the indoor unit.
No major electronic board failure was detected. However, a slightly loose connection in the unit’s box that was making noise was corrected. This anomaly was not the main cause of the problem, but it could cause less stable startups over time. An imperfect connection can also generate heat at the contact point, increasing the risk of premature failure. Our team therefore tightened, cleaned, and secured the affected connection points.
Condensate problem and line insulation
The second symptom, the presence of moisture and uneven performance, led us to inspect the drainage and insulation of the refrigerant lines. On a wall-mounted heat pump, a poorly oriented drain, partially blocked or subjected to a reverse slope can cause water accumulation. In winter, this moisture can promote ice formation, impair operation, and worry the owner.
We found that the path of one of the drains was not optimal. A slight accumulation of debris and an insufficient slope slowed the evacuation of condensate. It was not a complete blockage, but enough to cause irregular drainage. In some cycles, the water drained properly; in others, it temporarily stagnated, which explained the traces observed by the client.
We therefore:
- cleaned the drain;
- checked for complete drainage;
- corrected the slope on the accessible section;
- secured the conduit to prevent movement;
- inspected the line insulation;
- reinforced certain areas where the insulation was beginning to deteriorate;
- checked for any visible leaks around the fittings.
This step is essential in any wall-mounted heat pump repair, as a neglected drainage problem can lead to infiltration, a musty smell, ice buildup, or reduced efficiency. On the North Shore as well as on the South Shore, we often encounter systems that are still working but whose drainage has become less effective after several seasons of freezing, thawing, and sun exposure.
Coil cleaning and airflow control
Both outdoor units also showed a normal accumulation of dust, plant particles, and seasonal residues. The side wall being near an outdoor area with trees, vegetation, and variable airflow, the coils can gradually load up. Even a thin layer of dirt can reduce heat exchange and force the compressor to work harder.
We performed appropriate cleaning of the outdoor coil, without excessive pressure, to preserve the fins. The airflow was then checked during operation. After cleaning, the fan provided more uniform circulation, and the heat pump responded better to heating demands.
A common mistake is to wait until a unit is completely blocked before requesting service. However, a slightly clogged coil can already cause:
- higher electricity consumption;
- less stable heating;
- longer cycles;
- premature compressor wear;
- an increase in noise;
- a gradual loss of comfort.
For a system installed at height, maintenance is even more important because the owner cannot always easily inspect the back or sides of the unit. This is one of the reasons why periodic HVAC maintenance remains recommended, especially before periods of high demand.
Vibration correction and mechanical stabilization
The most delicate part of the intervention concerned the vibration. The wall mounts were solid, but the right unit transmitted resonance to the wall during certain startups. We therefore checked the unit's level, adjusted the support points, tightened the fastenings, and added a correction at the contact points to reduce vibration transfer.
A wall-mounted heat pump can produce a certain normal noise level, especially at startup or during a defrost cycle. What matters in repair is not just the noise itself, but its origin: mechanical vibration, unbalanced fan, poorly fixed panel, worn compressor, pipe in contact with the wall, loose support, or moving internal part.
In this case, the noise did not indicate a compressor failure. This was great news for the customer, as replacing a compressor is a much more costly intervention. After mechanical stabilization and support adjustments, the startup became smoother and vibration transmitted to the structure greatly decreased.
Operational tests after repair
Once corrections were made, our technicians restarted both systems in heating and ventilation modes, then observed several cycles. The goal was not just to confirm the unit started, but to ensure the system returned to stable operation.
We checked:
- indoor supply air temperature;
- response to thermostat demand;
- stability of the outdoor fan;
- noise reduction;
- absence of excessive vibration;
- the drainage of condensate;
- good communication between components;
- the condition of connections after operation;
- the regularity of cycles.
The result was clear: the Goodman wall-mounted heat pump operated more quietly, more stably, and more efficiently. The customer immediately noticed the difference in noise level. After a testing period, the indoor temperature stabilized more quickly, without intermittent behavior.
Practical advice given to the customer
At the end of the service call, we took the time to explain the likely causes of the problem and simple steps to take to prevent recurrence. At AirGreen, an HVAC repair is not limited to replacing a part or a quick adjustment. We want the customer to understand their system and recognize warning signs.
We recommended:
- to regularly clean the filters of indoor units;
- to keep the area around outdoor units clear;
- to monitor unusual noises at startup;
- to never ignore signs of water or moisture;
- to schedule maintenance before periods of heavy use;
- to have wall mounts checked if vibration occurs;
- to avoid improvised modifications on drains or cables;
- to contact an HVAC specialist if an error code appears.
An important point was also addressed: on a system installed at height, it is not recommended to attempt a complete cleaning of the outdoor unit yourself without safety equipment. A simple misdirected rinse or too much pressure can damage the fins, push water toward sensitive components, or worsen an existing problem.
Why this intervention perfectly illustrates the AirGreen approach
This repair in Montreal demonstrates the importance of a comprehensive diagnosis. The client might have thought the problem was only due to a lack of refrigerant or a faulty compressor. In reality, the situation combined several factors: mechanical vibration, imperfect drainage, necessary coil maintenance, and a connection to secure. None of these elements, taken separately, seemed dramatic. Together, they created a drop in comfort and legitimate concern.
This is exactly the type of situation where field experience makes the difference. Our technicians regularly work on wall-mounted heat pumps, wall air conditioners, multi-zone systems, central heat pumps, PTAC / VTAC units, and other HVAC equipment in Greater Montreal. This variety of interventions allows us to quickly recognize details that often escape a superficial inspection.
In Laval, Longueuil, on the North Shore and the South Shore, we often see systems that are still functional but whose performance is compromised by peripheral elements: poor drainage, weakened fastening, vibration, dirt buildup, damaged insulation, poorly protected wiring, or insufficient clearance. The role of good HVAC service is to identify these details before they become costly breakdowns.
Mistakes to avoid with a wall-mounted heat pump installed on wall supports
A wall installation has several advantages, but it must be properly monitored. Here are the mistakes we often encounter during service calls:
Ignoring a persistent vibration
A vibration that increases over time should never be taken lightly. It can come from a support, a panel, a fan, or a line in contact with the wall. The longer it lasts, the more it can weaken the fastenings and components.
Neglecting drainage
A slow-draining drain may seem minor, but it can cause moisture, freezing, odors, or damage around the indoor unit. Drainage must be clean, stable, and properly directed.
Letting coils get clogged
A wall-mounted heat pump needs efficient heat exchange. When the outdoor coil is dirty, the unit works harder to achieve the same result.
Ignoring electrical connections
Slightly loose connections can cause intermittent problems that are hard to diagnose. A professional check helps prevent a more serious failure.
Delaying maintenance until a complete breakdown
Preventive maintenance usually costs less than emergency repairs. It also extends the system’s lifespan and protects indoor comfort.
Restored performance and a reassured client
After our intervention, the two Goodman units were clean, stabilized, tested, and fully operational. The startup noise had been reduced, condensate drainage returned to normal, and heating performance was more consistent. The client especially appreciated that the repair did not require replacing a major component. Thanks to an accurate diagnosis, we were able to target the real causes of the problem and fix the situation effectively.
This type of service call perfectly reflects our mission at AirGreen: to provide serious, transparent, and lasting wall-mounted heat pump repair, with a full understanding of the installation, the building, and local weather conditions. Whether the service is in Montreal, Laval, Longueuil, on the North Shore or the South Shore, we apply the same method: listen to the symptoms, inspect the entire system, provide a clear diagnosis, make the necessary corrections, and verify the results before leaving the site.
A well-repaired wall-mounted heat pump should not just restart. It must operate stably, quietly, safely, and efficiently. That’s what we restored during this service on these Goodman units installed high up, in a residential setting where every detail mattered.