Installation of a Samsung Premium FJM dual-zone heat pump in a renovated attic in Pointe-Calumet

Installing comfort even before the walls were closed

This dual-zone heat pump installation in Pointe-Calumet took place in an environment very different from an already finished residential room. The photo shows an upper floor undergoing transformation: exposed framing, a sloped ceiling, sprayed polyurethane foam insulation, a skylight, visible plumbing pipes, and interior cladding that was still incomplete.

For this type of project, installing a wall-mounted heat pump does not simply involve attaching an indoor unit to a partition. We must anticipate the wall finishing, future air circulation, routing of the refrigerant lines, condensate drainage, access for maintenance, and the final placement of the furniture.

For this project, we installed a Samsung Premium FJM multi-zone heat pump, configured to power two indoor units from a single outdoor unit. The photo documents one of these two zones, set up in the attic portion of the residence.

An attic area that required precise structural preparation

The sloped ceilings and low walls of an attic floor often limit the available locations for a wall-mounted air conditioner. The unit must be installed high enough to distribute air effectively, but it cannot encroach on the roof slope, framing elements, or openings.

In this room, the most logical space was above the future opening, in a section where the wall was not yet finished. We therefore coordinated the installation with the progress of the renovation work.

A large sheet of drywall was installed on a wood structure prepared in advance. This method provides several advantages:

• a level, stable surface for the mounting plate;
• adequate support for the unit’s weight and vibrations;
• a clear reference point for future finishing work;
• uniform clearance around the unit;
• better-planned access to the fittings and drain.

Attaching the plate directly to a temporary surface or to poorly aligned wooden members could have created an undesirable slope. Even a slight leveling error can interfere with condensation-water drainage and eventually cause water to run inside.

Why the location above the opening was advantageous

The indoor unit was centered on the panel, above the future window or opening to be created in the roof slope. This positioning allows heated or cooled air to move toward the occupied part of the room rather than toward a confined corner.

In a finished attic, heat quickly accumulates near the ceiling during the summer. Roof surfaces can transmit a significant thermal load, even when the insulation is of good quality. A wall-mounted unit placed in the upper part of the area can draw in this warm air and treat it efficiently.

In heating mode, we must also consider the natural tendency of warm air to rise. The louver direction and ventilation speed are adjusted to project the air downward and promote uniform air circulation.

The presence of spray foam insulation on the roof slopes is beneficial to the building’s overall performance. However, it does not replace a thermal load calculation. The area, ceiling volume, windows, solar orientation, building-envelope airtightness, and room usage must all be considered before determining the required capacity.

An installation planned around the elements already in place

The work site presented several visible constraints:

• a black plumbing column to the left of the unit;
• a skylight beneath the selected location;
• framing studs that had to be preserved;
• a sloped ceiling with limited vertical space;
• electrical and mechanical conduits being prepared;
• finishing work that was to continue after our intervention.

The refrigerant lines and communication cable were routed toward the right side of the unit. This direction avoided the plumbing column and followed a path compatible with the structure.

In an open construction area, it may be tempting to route the pipes along the shortest path without considering the next stages. Instead, we verify that the route will not be blocked by drywall, siding, trim, a cabinet, or a structural element added later.

Drainage: a detail that must never be improvised

During cooling and dehumidification, the indoor unit produces condensation water. This water must be drained continuously, without any backfall or crushed section.

In a sloped ceiling, an incorrectly routed pipe can create a pocket of water. Possible consequences include:

• gurgling noise;
• odors;
• backflow into the condensate pan;
• a leak in the wall;
• damage to the finished drywall;
• development of deposits in the drain.

We therefore plan the drain slope before closing the walls. When gravity does not allow for reliable drainage, a condensate pump may be considered. In this project, the goal was to keep the route as simple and accessible as possible.

Why choose a Samsung Premium FJM for two zones

The Samsung FJM system, short for “Free Joint Multi,” allows several indoor units to be connected to a single outdoor unit. The current Premium lineup offers outdoor units in various capacities, including 20,000, 24,000, 30,000, and 36,000 BTU/h, and can power up to four zones depending on the model and selected combination. For this Pointe-Calumet project, the system was configured as a dual-zone system.

This configuration is particularly appealing in a home with multiple floors or rooms with different heating and cooling needs.

Each indoor unit has its own temperature setpoint. An attic bedroom exposed to the sun may therefore require more cooling than the room on the floor below. The system adjusts its operation to the actual demand of the active zones.

However, it is important to understand a key feature of multi-zone systems: units connected to the same outdoor unit generally operate in the same primary mode. They can have different set temperatures, but one zone normally cannot cool while the other heats.

Sizing based on the complete combination

For a dual-zone heat pump, the outdoor unit’s capacity must not be determined simply by adding the figures listed for the two indoor units.

We check, in particular:

• the heat load of each zone;
• the total connected capacity authorized by Samsung;
• the available capacity when both zones operate simultaneously;
• the total length of the lines;
• the height difference between the units;
• the low-temperature heating capacity;
• the specified piping dimensions;
• the required electrical supply;
• the performance of the exact pairing.

This step is essential in a room located directly beneath the roof. Two spaces with the same floor area can have very different needs depending on their windows and solar exposure.

The Samsung Premium FJM line is designed for cold climates. Samsung indicates that heating capacity is maintained at 100% at −15 °C and that heat output remains available at −25 °C for the applicable configurations. The current model also uses R-32 refrigerant and includes automatic addressing and connection-checking functions to facilitate the commissioning of multi-zone systems.

The installation’s precise performance remains linked to the outdoor unit’s model number, the two selected indoor units, and their certified combination. That is why we always verify the nameplates and technical documents rather than infer capacity from the unit’s appearance.

An indoor unit integrated before the attic was finished

Installing the unit during the renovation offered a significant advantage: we could prepare the mechanical pathways before the finishes were fully installed.

This approach generally makes it possible to achieve:

• fewer visible ducts;
• fewer PVC moldings;
• a more direct route to the outdoors;
• better coordination with the electrician;
• a cleaner finish;
• fewer holes after the painting work.

However, it requires precise communication among the various trades. The unit must be protected from dust, impacts, paint, and debris produced during the work.

We also recommend not enclosing critical connections in an inaccessible cavity. A visually discreet installation must never compromise the ability to carry out an inspection, diagnosis, or repair.

Protecting the unit during the work

A heat pump should not be used as a temporary heating or cooling system during very dusty work without appropriate protective measures.

Drywall dust, sawdust, and insulation particles can accumulate on:

• the filters;
• the indoor heat exchanger;
• the blower wheel;
• the dampers;
• the sensors;
• the electronic components.

After the work is complete, we recommend inspecting the filters and indoor unit before regular use. Significant buildup on the blower wheel can reduce airflow and cause noise.

Commissioning a dual-zone system

Commissioning a multi-zone HVAC system involves more steps than a simple startup test.

Our technicians must, in particular:

1. confirm that each indoor unit is connected to the correct refrigeration circuit;
2. check the electrical connections and communication wires;
3. perform leak-tightness and evacuation procedures;
4. confirm the total piping length;
5. adjust the refrigerant charge when required by the manufacturer;
6. check the drainage from each drain;
7. test both zones in operation;
8. control supply-air and return-air temperatures;
9. program the remotes and available functions;
10. explain mode and setpoint management to the client.

The Samsung Premium FJM platform also offers compatibility with the SmartThings app in supported configurations. It can allow users to adjust settings remotely, monitor operation, and manage zones more easily. The availability of each function must be confirmed based on the indoor units and accessories installed.

What this Pointe-Calumet project teaches homeowners carrying out renovations

Plan for the heat pump before closing the walls

One of the best decisions in a renovation project is to contact the heating, ventilation, and air conditioning contractor before installing the drywall.

This coordination makes it possible to determine:

• the exact location of the indoor units;
• the necessary reinforcements in the walls;
• the piping route;
• the drain location;
• the electrical circuit;
• the outdoor unit location;
• the clearances required for maintenance;
• the openings that must remain accessible.

At the Pointe-Calumet residence, the mounting panel visible in the photo was an integral part of this preparation. It made it possible to install the unit on a straight base while the framing remained open.

Common mistakes to avoid in an attic room

Install the unit too close to the sloped ceiling

Insufficient space above the appliance can restrict air intake and complicate removing the casing during maintenance.

Direct the airflow toward a beam or a short slope

The air can immediately bounce off a nearby surface and return toward the unit without circulating properly through the room.

Neglect the future finish

A unit positioned correctly on an open frame can become off-center once the trim, cabinets, or doors are added.

Underestimate the solar load

A skylight can bring in a great deal of heat during the summer. Its impact must be incorporated into the sizing.

Choose an excessive capacity

An oversized heat pump can quickly reach the requested temperature without operating long enough to ensure optimal dehumidification.

Hide all connections without access

A completely enclosed finish can turn a minor maintenance intervention into demolition work.

LogisVert financial assistance: verify the exact pairing

A Samsung multi-zone heat pump may be eligible for financial assistance when the complete combination appears on the applicable list at the time of installation and all program conditions are met.

Hydro-Québec specifies that the lists of eligible models and the amounts may change. Verification must therefore be based on the AHRI number and the exact combination, including the outdoor unit and indoor units, rather than solely on the commercial name “Premium FJM.”

Under the current LogisVert program rules, assistance for an efficient heat pump is calculated based on its heating capacity at −8 °C. Hydro-Québec indicates that assistance may reach $6,700, depending on the system’s capacity and efficiency level.

We recommend keeping:

• detailed invoice;
• model numbers;
• serial numbers;
• AHRI reference;
• installation date;
• photos of the rating plates;
• proof of payment.

A result designed to remain discreet after finishing

At the stage shown in the photographs, the site still looks highly technical: exposed studs, insulating foam, wiring, piping, and construction materials on the floor. Yet this is precisely the phase in which much of the final result’s quality is determined.

Once the ceiling and walls are finished, the panel will be integrated into the room, and the Samsung unit will become one of the few visible elements of the entire installation. The pipes, reinforcements, and passages prepared behind the surfaces will no longer be noticeable, but they will continue to influence the system’s reliability for years.

This installation in Pointe-Calumet illustrates how we work at AirGreen: we do not view the heat pump as an appliance added at the end of a project. We integrate it into the structure, finish, and future use of the spaces.

The AirGreen approach to multi-zone installations

For our heat pump projects in Montreal, Laval, Longueuil, on the North Shore and South Shore, we pay particular attention to details that are not always visible on a basic quote:

• calculation and distribution of heating loads;
• selection of the certified combination;
• unit clearances;
• drain locations;
• accessibility of the connections;
• vibration protection;
• coordination with the finishing work;
• vacuuming and leak testing;
• complete testing of each zone;
• assistance with rebate documents.

For this Samsung Premium FJM dual-zone system in Pointe-Calumet, the main challenge was not simply heating and cooling two spaces. One of the units had to be integrated into an attic under renovation, between a sloped ceiling, a skylight, and existing mechanical components.

Preparing the support, centering the unit, planning the pipe routes, and anticipating the finishing work made it possible to complete a clean, functional installation adapted to the residence’s unique architecture.