Installation of a CANAIR 4C28 wall-mounted heat pump in Saint-Paul-d’Abbotsford, Montérégie

A high wall-mounted installation designed to preserve space, airflow, and system reliability

At Saint-Paul-d’Abbotsford, every wall-mounted heat pump project must be adapted to the building's actual configuration. In this case, the CANAIR 4C28 outdoor unit had to be installed on a brick façade where several air-conditioning units already occupied the available space. The window directly above, neighboring equipment, and existing lines considerably limited the positioning options.

Our AirGreen team therefore chose an installation on sturdy wall brackets, at a height that clears the lower part of the façade while maintaining sufficient space around the condenser. The result is a compact, stable installation suited to a dense residential environment where every clearance matters.

This configuration clearly illustrates our approach: we never choose the location of an outdoor unit solely based on the shortest distance. We also assess the wall structure, future access for maintenance, airflow, drainage, proximity to windows, the presence of other HVAC systems, and the constraints specific to Montérégie's winters.

A façade already occupied by several HVAC units

The project photograph shows a common situation in apartment buildings, mixed-use buildings, and certain properties that have been modified over the years: several outdoor units are grouped on the same façade.

In such an environment, a poor positioning decision can lead to several problems:

• recirculation of hot air discharged during cooling;
• insufficient clearance in front of or behind the condenser;
• difficult access for future HVAC maintenance;
• snow or ice buildup beneath the unit;
• vibrations transmitted to the masonry;
• partial obstruction of a window;
• difficulty replacing a nearby unit;
• premature deterioration of the refrigerant lines.

We installed the CANAIR 4C28 in the center of the available space, on a pair of metal brackets secured to the masonry. The unit remains sufficiently clear of the wall to allow air to enter through the rear coil, while its front remains unobstructed so the fan can discharge air without significant obstruction.

The elevated installation also helps protect the unit from snow accumulation on the ground. This precaution is particularly relevant in Saint-Paul-d’Abbotsford, where episodes of snow, freezing rain, and frost can create demanding conditions for a heat pump used as a heating source.

Why choosing the CANAIR 4C28 series is relevant in Quebec

The CANAIR 4C28 series is designed for heating and cooling under conditions corresponding to Quebec's climate. It uses variable-compressor technology, commonly known as Inverter technology. The compressor can therefore modulate its operation instead of constantly starting and stopping at full power.

This modulation provides tangible benefits:

• more stable indoor temperature;
• electricity consumption better matched to actual demand;
• less abrupt start-ups;
• generally quieter operation;
• rapid temperature increases or decreases when needed;
• more consistent heating during cold periods.

According to the manufacturer's technical documentation, the 4C28 single-zone lineup includes cooling capacities ranging from 9,000 to 33,000 BTU/h, with efficiencies of up to 27.4 SEER2 and 13.5 HSPF2, depending on the selected combination. Single-zone models are designed to provide heating down to an outdoor temperature of -30 °C. The series also uses R-454B refrigerant and has the cold-climate certification indicated in the manufacturer's brochure.

However, the exact capacity installed in a building must never be determined solely from the visible size of the condenser. At AirGreen, we select the capacity based on several factors:

• area to be conditioned;
• ceiling height;
• wall and roof insulation;
• window dimensions and orientation;
• number of floors;
• sun exposure;
• heat loss;
• room configuration;
• intended use of the heat pump as the primary or supplementary heating system.

An oversized unit can quickly reach the desired temperature, but it may operate in cycles that are too short and control humidity less effectively in summer. Conversely, an undersized unit may run continuously without maintaining the desired comfort level during the coldest periods. Proper sizing therefore remains essential, even with an Inverter heat pump.

A heat pump designed for heating and cooling

The CANAIR 4C28 wall-mounted heat pump is not used only for cooling. In heating mode, it captures thermal energy available in the outdoor air and transfers it indoors. This technology makes it possible to produce more useful heat than the electricity consumed directly by the compressor and fans, particularly when the outdoor temperature remains moderate.

The 4C28 series offers several practical features presented by the manufacturer:

• Turbo mode, to reach the selected temperature more quickly;
• silent mode, particularly useful in bedrooms and resting areas;
• Follow Me function, which uses the remote control’s location as the temperature reference;
• automatic restart function after a power outage;
• coil self-cleaning and drying function;
• outdoor heating cables designed to reduce ice buildup;
• optional Wi-Fi control;
• A2L refrigerant leak detection;
• protection against cold drafts when starting in heating mode.

These features do not replace a thorough installation, but they improve the system’s everyday use when combined with proper positioning and compliant commissioning.

Installation details that make a difference on a brick facade

Wall brackets suited to the weight and vibrations

The outdoor unit visible in this installation does not rest on a balcony, roof, or ground-level slab. It is supported by metal brackets anchored to the wall.

This type of installation requires special attention. Exterior brick must not be treated as a simple decorative surface on which the unit can be mounted without analysis. We must consider the condition of the masonry, the location of the joints, the structure behind the cladding, and the load imposed by the unit.

A heat pump also produces slight vibrations during operation. Insufficient anchoring or overly flexible supports can cause:

• a resonance noise in the building;
• noticeable movement of the unit;
• gradual loosening of the fasteners;
• premature wear of certain components;
• noise complaints in adjacent rooms.

Our installers use supports sized for the equipment and check their alignment before final fastening. The unit must be stable and properly leveled so that the water produced during defrost cycles can drain as intended.

Keep the condenser's air intake and outlet clear

In the photo, the front of the CANAIR remains open. No panel, balcony, or large obstruction directly blocks the fan.

This detail is important. When the air discharged by the unit immediately strikes a surface and returns to the coil, the system may reabsorb some of the air it has just discharged. In summer, this increases the temperature of the air entering the condenser and can reduce cooling efficiency. In winter, poor airflow can also affect operation and promote certain ice buildups.

In an installation involving several units, we must also consider the simultaneous operation of nearby units. The goal is to limit interactions between the different air discharges, even when the façade offers little space.

Handle refrigerant lines with care

A wall-mounted heat pump installation includes two insulated copper lines, a communication cable, and, depending on the configuration, a condensate drain line. These components connect the indoor unit to the outdoor condenser.

The CANAIR 4C28 series does not use the same piping diameters for all capacities. According to the documentation:

• the 9,000 and 12,000 BTU models use 1/4 in. and 3/8 in. fittings;
• the 18,000 BTU model uses 1/4 in. and 1/2 in. fittings;
• the 24,000 BTU model uses 3/8 in. and 5/8 in. fittings;
• the 33,000 BTU model uses 3/8 in. and 3/4 in. fittings.

Installing piping with the wrong diameter or modifying an existing line without checking its compatibility can reduce performance and compromise compressor reliability. When replacing equipment, we therefore never assume that the existing lines can automatically be reused.

We check their diameter, condition, length, insulation, and compatibility with the new refrigerant. Pressurizing the system with nitrogen and performing a thorough vacuum then help reduce the risk of leaks, residual moisture, or contaminants in the circuit.

Special attention to R-454B refrigerant

The CANAIR 4C28 series uses R-454B, an A2L-classified refrigerant. This classification indicates low toxicity and reduced flammability, but it still requires appropriate handling and installation practices.

The manufacturer notably incorporates a leak detection function. When a leak is detected by the indoor unit’s sensor, an error code may be displayed and operation is automatically interrupted.

For the owner, this technological development mainly means that it is preferable to entrust the installation, repair, and relocation of the system to technicians trained to work with A2L refrigerants. Improvised methods and connections made without the proper tools should be avoided.

Plan for drainage during defrost cycles

In heating mode, an outdoor heat pump can accumulate frost on its coil. The system then periodically initiates a defrost cycle. The resulting water must be able to drain away from the base of the unit without accumulating on a sensitive surface or forming a mass of ice around the condenser.

The wall-mounted installation observed in this project makes it easier to keep the area beneath the unit clear. Nevertheless, it is important to check where the water will flow, especially when a walkway, driveway, window, or piece of equipment is located below.

A common mistake is to install a unit very close to the ground without taking snow depth or ice formation into account. In some properties in Montreal, Laval, Longueuil, the North Shore, and the South Shore, we find units that are almost buried after just a few storms. Air circulation is then restricted, and the owner must clear the unit under difficult conditions.

Maintain future access for servicing

A successful installation does not end on the day the system is commissioned. The unit will eventually need to be inspected, cleaned, or repaired.

Even when a condenser is installed at a height, realistic access to the service panels, refrigerant connections, and electrical components must be maintained. In this project, the chosen positioning clearly distinguishes the unit’s service side despite the proximity of the other systems.

During HVAC maintenance, the technician must be able to:

• check the connections;
• measure the operating parameters;
• inspect the wires and terminal blocks;
• clean the coil;
• check the condition of the fan;
• look for signs of corrosion;
• confirm that the drainage remains clear.

Placing a unit in a space that is too tight may reduce the initial cost or temporarily simplify the routing of lines, but it can considerably increase the cost of future service calls.

Mistakes to avoid during a comparable installation

For a property owner or building manager in Saint-Paul-d’Abbotsford, several checks should be completed before authorizing the installation of a wall-mounted heat pump:

Installing the condenser too close to a window

An outdoor unit can produce normal fan and compressor noise. Mounting it directly against the structure of a bedroom or immediately beside an open window can make this noise more noticeable.

Neglecting the wall’s load-bearing capacity

Masonry may appear solid, but inadequate fastening in aging brick or a weakened mortar joint does not provide a sufficient base.

Blocking the rear coil

The condenser must draw in a significant volume of air. Insufficient clearance behind the unit reduces this capacity.

Reusing old lines without verification

The diameter, residual oil, condition of the insulation, and type of refrigerant must be verified before any reuse.

Forgetting about snow accumulation

A low-mounted heat pump can be obstructed during the winter. A wall-mounted or elevated support reduces this risk when installed correctly.

Choosing the capacity based solely on the floor area

Two homes of the same size can have very different needs depending on their insulation, windows, and exposure.

The result: a compact installation that is consistent with the building

This CANAIR 4C28 wall-mounted heat pump installation in Saint-Paul-d’Abbotsford shows that a limited space can be used effectively when it is assessed before work begins.

The outdoor unit is securely installed at height, its front remains unobstructed, and its location follows the layout of the equipment already in place. The owner therefore benefits from a system capable of providing summer cooling and contributing to heating during cold periods, without taking up ground space around the building.

At AirGreen, we carry out this type of HVAC installation throughout Greater Montreal and Montérégie, including Montreal, Laval, Longueuil, the North Shore, and the South Shore. Each project is planned according to the property's actual structure, comfort requirements, available electrical capacity, and the technical requirements of the selected unit.

Our objective remains the same: to install a heat pump in a way that preserves its performance, durability, and accessibility, rather than simply finding the quickest place to mount it.