Installation of a CANAIR 4C28 wall-mounted heat pump in Sainte-Angèle-de-Monnoir, in Montérégie

A wall-mounted installation adapted to an unconventional space with an open ceiling

At Sainte-Angèle-de-Monnoir, we completed the installation of a CANAIR 4C28 wall-mounted heat pump in a room whose architecture required much more precise planning than a conventional residential installation. In the project photo, you can see a dark-painted open ceiling, several exposed ducts and pipes, suspended light fixtures, a wall-mounted camera, and a large opening covered by curtains. All of these elements reduced the number of genuinely suitable locations for the indoor unit.

Our objective was therefore not simply to mount a unit on an available wall. We had to determine a position that would allow the heat pump to distribute air efficiently, remain accessible for maintenance, and integrate neatly into an industrial-style interior.

The CANAIR 4C28 indoor unit was ultimately installed high on the dark wall, just above the curtain rod. This location makes clever use of a surface that would otherwise be difficult to utilize, while keeping the front section and air-discharge louvers completely unobstructed.

The result is a compact, functional HVAC installation that is visually consistent with the existing layout.

Why the indoor unit’s location was crucial

In a room with a conventional ceiling, choosing the location is often fairly straightforward. Here, the presence of pipes, beams, cables, and suspended light fixtures required a more thorough analysis.

We specifically had to take the following elements into account:

• the path of the air leaving the unit;
• the clearance required in front of the louvers;
• the proximity of the ceiling and exposed ducts;
• future access to the filters and indoor heat exchanger;
• the route of the condensate drain;
• the layout of the refrigerant lines;
• the presence of the camera installed on the adjacent wall;
• the opening of the curtains beneath the unit;
• the heat sources created by the light fixtures.

A heat pump installed too close to an obstacle may recirculate its own air. It then detects a temperature that does not accurately represent the temperature of the entire room. This can lead to irregular cycles, poorer heat distribution, and discomfort in areas farther away.

In this project, the unit was positioned to preserve a clear discharge area. The louvers can direct air toward the center of the room without it being immediately blocked by a beam, pipe, or light fixture.

A Successful Integration into an Industrial Décor

The white indoor unit creates a sharp contrast with the dark wall and open ceiling. Rather than trying to completely conceal the heat pump, we opted for a straight, proportionate installation in relation to the opening beneath the unit.

This type of installation requires particular attention to alignment. On a dark wall, a slightly tilted or off-center unit quickly becomes noticeable. Positioning must also account for the front panel opening, since it must be able to be raised when cleaning the filters and carrying out inspections.

The presence of a curtain rod directly beneath the unit was also an important consideration. The curtains must not rise in front of the air intake or enter the path of the louvers. A fabric obstruction can reduce airflow, trap dust, and interfere with the system's operation.

We therefore selected a location where the unit would remain above the area occupied by the fabric, without compromising access to the window or opening.

The CANAIR 4C28 Series: A Heat Pump Designed for the Quebec Climate

The CANAIR 4C28 is a range of wall-mounted heat pumps with Inverter technology, available in single-zone and multizone configurations. According to the manufacturer's documentation, the single-zone series includes nominal cooling capacities of 9,000, 12,000, 18,000, 24,000, and 33,000 BTU/h, along with a 6,000 BTU indoor unit intended for multizone configurations.

The exact capacity of the unit shown in the photo cannot be confirmed from its casing alone. The sizing selected for each project should always be based on the volume to be treated, insulation, fenestration, room use, internal gains, and heat losses, rather than on a visual estimate.

Depending on the selected model, the range reaches up to 27.4 SEER2 and up to 13.5 HSPF2, with heating operation advertised down to an outdoor temperature of -30 °C. It uses R-454B refrigerant, and the models listed in the brochure are certified for cold climates.

Inverter technology and actual comfort in the room

An Inverter heat pump is not limited to operating fully on or fully off. The compressor can adjust its speed to adapt heating or cooling output to the room's immediate needs.

This modulation offers several tangible benefits:

• more stable indoor temperature;
• fewer abrupt variations between cycles;
• energy consumption better matched to demand;
• generally quieter operation at partial load;
• faster attainment of the requested temperature;
• better management of the transitional periods in spring and fall.

In the photographed space, this modulation capability is particularly relevant. Open ceilings and irregular volumes can create temperature differences between the lower and upper parts of the room. Heat generated by lighting can also change requirements depending on occupancy.

A properly sized Inverter unit can gradually adjust its output instead of repeatedly starting and stopping.

Performance varies according to the selected capacity

The CANAIR 4C28 series meets a range of needs, but each capacity has its own electrical, acoustic, and refrigeration characteristics.

For example, the technical documentation indicates:

• 9,000 BTU/h: up to 27.4 SEER2;
• 12,000 BTU/h: up to 25.4 SEER2;
• 18,000 BTU/h: up to 21.4 SEER2;
• 24,000 BTU/h: up to 21.0 SEER2;
• 33,000 BTU/h: up to 19.5 SEER2.

These figures do not mean that a smaller-capacity unit is automatically preferable. An undersized heat pump may run almost continuously without reaching the desired temperature during periods of extreme cold. Conversely, an oversized unit can cause short cycling, less effective dehumidification in summer, and less comfortable air distribution.

At AirGreen, we therefore assess the building before recommending a capacity. For a heat pump installation in Sainte-Angèle-de-Monnoir, we must consider the conditions specific to the homes, businesses, workshops, and converted agricultural buildings found in this area of Montérégie.

Operation designed down to -30 °C

The single-zone CANAIR 4C28 units are advertised as operating in heating mode down to -30 °C. This feature is important in Quebec, but it must be properly understood.

“Operation down to -30 °C” does not necessarily mean that the unit retains its full nominal capacity at that temperature. As with any heat pump, available capacity and the coefficient of performance may decrease as the outdoor temperature drops.

The brochure provides heating capacities at -15 °C, including:

• 11,500 BTU/h for the 9,000 and 12,000 BTU models;
• 18,000 BTU/h for the 18,000 BTU model;
• 24,200 BTU/h for the 24,000 BTU model;
• 35,000 BTU/h for the 33,000 BTU model.

This data is much more useful than simple nominal capacity when determining whether the heat pump will cover a significant portion of winter heating needs.

In some buildings, supplemental heating remains necessary during cold snaps. This decision depends on the heat-loss calculation, low-temperature capacity, and the level of redundancy desired by the owner.

Built-in heating cables for winter conditions

The series includes heating cables installed at the base of the outdoor unit and around the compressor. Their purpose is to limit ice buildup and facilitate startup in cold weather.

The outdoor unit’s installation nevertheless remains decisive. Even a unit designed for winter conditions can encounter problems when installed too close to the ground or directly in an area where snow accumulates.

We plan for the following, in particular:

• a sufficiently elevated support;
• adequate clearance beneath the unit;
• unobstructed drainage for defrost water;
• an appropriate distance from the walls;
• a location that is not directly beneath a downspout;
• safe access for HVAC maintenance.

In Sainte-Angèle-de-Monnoir, snow accumulation, wind, and freezing conditions must be taken into account from the installation design stage.

R-454B refrigerant and leak detection

The CANAIR 4C28 uses R-454B, an A2L-classified refrigerant. The documentation mentions a leak detection device in the indoor unit. When a leak is detected, the unit displays an error code and shuts down automatically.

This technological development affects installation practices. The work must be performed with the appropriate tools, in accordance with the manufacturer’s requirements and the applicable rules for A2L refrigerants.

A professional installation includes, among other things:

1. proper preparation of flared connections;
2. the use of tools compatible with the refrigerant;
3. a leak test;
4. thorough evacuation;
5. validation of the piping lengths;
6. verification of the electrical connections;
7. a controlled system start-up.

Improper evacuation can leave moisture and non-condensable gases in the circuit. This can reduce performance, increase pressures, and shorten the compressor’s service life.

Useful Everyday Features

The CANAIR 4C28 series includes several features designed for comfort and maintenance:

Turbo Mode

Turbo mode temporarily increases capacity to reach the selected temperature more quickly, in both heating and cooling modes.

Silent Mode

The silent mode reduces the noise level for periods when acoustic comfort is a priority, especially in the evening or in a room occupied for several hours.

“Follow Me” Function

When this function is enabled, the remote control serves as the temperature reference point. It can be useful when the indoor unit is installed high up, since the temperature near the ceiling is not always representative of the temperature felt by occupants.

However, avoid leaving the remote control near a light fixture, a sunny window, or another heat source.

Self-Cleaning Function

The self-cleaning function helps dry and clean the heat exchangers to limit conditions conducive to odors, mold, and residual moisture.

However, it does not replace manual filter cleaning or periodic heat pump maintenance.

Automatic Restart

After a power outage, the unit may resume operation with the previously selected settings. This feature is convenient in areas where occasional outages may occur during severe weather.

Optional Wi-Fi Control

An optional Wi-Fi module may allow control of the unit from a smart device. Before installation, verify the exact compatibility of the module, application, and unit version.

Technical details that affect installation

Depending on capacity, the units in the series use different refrigerant piping sizes.

The brochure specifically states:

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

These differences are important when replacing an old heat pump. Existing piping should never be reused automatically simply because it already passes through the wall. We must check its diameter, condition, length, cleanliness, and compatibility with the new system.

The selected capacity also affects the electrical circuit. According to the documentation, the maximum protection rating ranges from 15 to 35 A for single-zone models. The circuit must be validated based on the nameplate of the equipment actually installed, rather than on a general estimate.

Mistakes to avoid in a room with an open ceiling

This CANAIR wall-mounted heat pump project in Sainte-Angèle-de-Monnoir illustrates several common mistakes we strive to prevent.

Installing the unit too close to a beam

A beam in front of or above the unit can reduce airflow and make it difficult to open the panel.

Neglecting heat stratification

In a high-ceilinged space, warm air naturally rises. The louver direction and fan speed must be adjusted to bring the heat back down toward the occupied area.

Placing the unit near a heat source

Visible light fixtures near the unit produce heat. The temperature sensor must not be influenced to the point of affecting the system's operation.

Blocking access with curtains

Curtains can obstruct the air intake, airflow, or access to the filters. Their movement and maximum height must be taken into account.

Forgetting the drain route

The drain must maintain an adequate slope when gravity drainage is used. A reverse slope can cause backflow, water noise, or an indoor leak.

Choosing capacity based solely on floor area

Two rooms with the same floor area can have very different needs. Ceiling height, solar orientation, insulation, windows, electrical appliances, and the number of occupants significantly change the actual load.

The Importance of Maintenance After Installation

A properly installed wall-mounted heat pump must also be serviced regularly.

In an environment with exposed ductwork, textiles, and an open ceiling, dust may circulate more than it would in a fully enclosed residential room. The filters should therefore be inspected frequently, especially during the first few weeks of use.

We recommend:

• clean the filters according to the level of use;
• check that the curtains do not hang in front of the unit;
• keep the upper air intake clear;
• monitor the drain flow in summer;
• remove snow around the outdoor unit;
• avoid using a high-pressure water jet on the coils;
• schedule professional maintenance when internal buildup becomes visible.

A clogged filter reduces airflow. The unit may then run longer, become noisier, and distribute heat or cooling less efficiently.

A suitable solution for Sainte-Angèle-de-Monnoir and the Montérégie region

This installation demonstrates that a wall-mounted heat pump can be effectively integrated into a non-conventional space when the location is chosen based on a complete technical analysis.

The CANAIR 4C28 offers a wide range of capacities, Inverter technology, operation advertised down to -30 °C, and several features suited to Quebec's climate. However, the unit's specifications never replace installation quality.

At AirGreen, we carry out wall-mounted heat pump installations in Sainte-Angèle-de-Monnoir, on the South Shore, in Longueuil, Montreal, Laval, and on the North Shore. Each project is planned according to the building, available space, piping route, drainage, electrical supply, and desired comfort level.

In this project, the dark wall, open ceiling, exposed ductwork, pendant lights, and curtains required precise execution. The indoor unit was positioned to preserve its airflow, accessibility, and visual integration.

It is this combination of sizing, preparation, HVAC installation, and finishing that enables a heat pump to provide reliable comfort, rather than the mere presence of a unit on the wall.