Installation of an ELIOS Central-Elios electric furnace compatible with R-454B in Otterburn Park, Montérégie

A central integration completed in a particularly narrow mechanical space

At Otterburn Park, we installed an ELIOS Central-Elios electric furnace compatible with an R-454B refrigerant heat pump in a basement where the available space required precise planning. The photograph taken during the work clearly shows the project’s main challenge: the new indoor unit had to be inserted between a large existing duct and a wooden partition, in a mechanical passage already occupied by several installations.

In this context, it was not enough to choose a furnace matching the home’s heating capacity. We also had to verify the cabinet width, the available height beneath the ducts, access to the service panels, the position of the refrigerant connections and the possibility of modifying the ventilation network without creating excessive restriction.

The installed system is part of the Central-Elios line, designed to operate with an inverter-technology central heat pump. The component visible in the photo is the system’s indoor unit: it contains the central fan, the coil associated with the heat pump and, depending on the selected configuration, the electrical elements used for auxiliary heating.

An installation that had to comply with just a few centimetres of clearance

The ELIOS unit is positioned vertically in a very narrow area. On the left, the duct network occupies almost all the available depth. On the right, the wooden structure defines a passage to another part of the basement.

This situation requires several constraints to be considered simultaneously:

• the furnace’s actual width;
• the depth required to connect the ducts;
• opening the front panels;
• the position of the condensate drain;
• access to the refrigerant connections;
• the electrical wiring route;
• future filter replacement;
• the ability to remove the motor or coil during a repair.

An installation can seem perfectly fitted on the day of the work, yet become highly problematic a few years later if a panel can no longer be removed. We therefore paid particular attention to the cabinet’s orientation and the space left in front of the service areas.

Why the size of the indoor unit was decisive

The Central-Elios product line is available in several capacities, and the dimensions of the indoor cabinet vary by model. The technical documentation indicates, among other things:

• 24,000 BTUs: 17.52 in. wide, 21.02 in. deep, and 45 in. high;
• 30,000 and 36,000 BTUs: 21.02 in. wide, 21.02 in. deep, and 49.02 in. high;
• 48,000 and 60,000 BTUs: 24.49 in. wide, 21.02 in. deep, and 52.99 in. high.

These differences become very important in a space like this one. A variation of a few inches can determine whether the appliance can be installed without moving a partition, rebuilding a large section of ductwork, or blocking access to the components.

The rating plate visible in the photograph does not make it possible to determine the exact model with certainty. We therefore cannot confirm the installed capacity based solely on the image. The precise model must be verified on the invoice, technical file, or appliance label.

An electric furnace integrated with a central heat pump

In everyday language, many homeowners use the term electric furnace to refer to the central unit that distributes warm and cool air throughout the house. Technically, this component may also be called a fan coil or air handler.

Its role is not limited to electric heating. It contributes to the system’s overall operation:

1. it draws air from the residence through the return ducts;
2. it passes this air through the filter;
3. it directs it toward the indoor coil;
4. it reheats or cools it according to the selected mode;
5. it redistributes treated air throughout the rooms;
6. it activates the supplemental electric elements when necessary.

The central heat pump generally remains the primary source of heating when conditions allow. The electric elements supplement its capacity during very cold periods, certain defrost cycles, or emergency heating mode.

R-454B: a refrigerant, not the furnace number

The designation R-454B refers to the refrigerant used in the heat pump circuit. This fluid circulates between the outdoor unit and the coil installed in the indoor unit.

It is important to distinguish between them:

• the brand: ELIOS;
• the product line: Central-Elios;
• the indoor unit model;
• the outdoor unit model;
• the capacity in BTUs;
• the electric element capacity;
• the refrigerant: R-454B.

This distinction becomes essential when it is necessary to order a part, register a warranty, verify eligibility for financial assistance, or prepare for future maintenance.

A system designed for Quebec’s climate conditions

The Central-Elios line is presented as a central system for cold climates. According to the manufacturer’s documentation, it can operate in heating mode down to -30 °C. The brochure also indicates that it maintains between 69% and 76% of its rated capacity at -30 °C, depending on the selected capacity.

For a residence in Otterburn Park, this feature is relevant, but it must be interpreted correctly. The fact that a heat pump continues to operate at very low temperatures does not necessarily mean that it will cover all of the building’s heat loss on its own.

Actual performance depends on several factors:

• the level of insulation;
• the home’s airtightness;
• floor area;
• the number of floors;
• the number of windows;
• wind exposure;
• the desired indoor temperature;
• the heat pump’s capacity at low temperatures;
• the capacity of the auxiliary electric heating.

That is why sizing must be performed for the building, rather than based solely on an approximate rule using floor area.

Inverter technology and temperature stability

The Central-Elios heat pump uses an Inverter compressor. Unlike a traditional system that operates mainly at full capacity or is off, a variable-speed compressor can modulate its output.

This modulation offers several benefits when properly configured:

• longer cycles;
• fewer sudden temperature variations;
• consumption better suited to actual needs;
• generally quieter operation;
• greater comfort stability;
• fewer repeated starts.

However, Inverter technology cannot compensate for inadequate ductwork. If the return air duct is too small or if the transition above the unit creates a restriction, the system will not be able to move the required volume of air.

Integration with the existing ductwork

The photograph shows a large metal duct adjacent to the furnace. During this type of replacement, we must decide which sections can be kept and which need to be modified.

The challenge is to connect the new cabinet without reducing the air passage area. A transition that is too short or too abrupt can create turbulence and increase static pressure.

A proper adaptation must notably:

• maintain a sufficient passage area;
• avoid very tight angles;
• limit air leaks;
• withstand vibrations;
• allow access to the panels;
• properly support the weight of the ducts;
• fit within the dimensions of the new unit.

The existing ductwork often represents a significant part of the installation. Even the best central heat pump will not deliver the expected results if air does not circulate properly.

Static pressure: an often-overlooked factor

Static pressure is the resistance the fan must overcome to move air through the system. It can increase when:

• the filter is too restrictive;
• the ducts are undersized;
• several registers are closed;
• the return air is insufficient;
• a transition is poorly designed;
• the coil is dirty;
• a flexible duct is crushed.

Excessive pressure can cause noise, reduce airflow, and increase the effort required from the motor.

In a project such as the one in Otterburn Park, the proximity of the ducts and structures makes this verification particularly important. Physically installing the furnace is only the first step; commissioning must confirm that the entire system is operating properly.

Auxiliary electric heating must be accurately sized

The Central-Elios documentation mentions the availability of auxiliary electric heating coils ranging from 3 to 25 kW.

The capacity choice must not be arbitrary. A larger element can provide more backup capacity, but it also requires:

• a larger electrical circuit;
• suitable conductors;
• appropriate protection;
• sufficient capacity in the main panel;
• coordination with the home's other loads.

Excessive capacity can lead to unnecessary electrical work. Insufficient capacity can leave the home without adequate backup during the coldest periods.

We therefore analyze the heat loss, the heat pump capacity, and electrical availability before determining the auxiliary heating.

Reliable drainage for summer air conditioning

In summer, the indoor coil cools the air and removes some of its moisture. The water produced must flow into a condensate drain.

In a tight space, the drain route must be planned so that it does not block the service panels. It must also maintain a continuous slope and remain accessible for cleaning.

The most common errors include:

• an improper slope;
• a drain that is too small;
• the absence of a cleanout;
• a leaky connection;
• a pipe placed in front of a panel;
• an inadequate trap;
• drainage toward an unsuitable area.

A condensate leak can damage the floor, wooden structure, or materials stored around the unit.

Built-in leak detection for R-454B

The Central-Elios system includes a sensor designed to monitor for a possible refrigerant leak. According to the documentation, this device can stop the compressor, maintain airflow, and generate a service alert.

This feature adds a safety measure, but it does not replace installation quality. Technicians must always:

• use compatible tools;
• make clean connections;
• perform a pressure test;
• check for leaks;
• perform an adequate vacuum evacuation;
• comply with the piping length;
• confirm the refrigerant charge;
• follow the manufacturer's requirements.

R-454B is part of the new generation of refrigerants and requires procedures adapted to its characteristics.

The published performance ratings for the Central-Elios product line

According to the technical table, Central-Elios models offer capacities from 24,000 to 60,000 BTU. Their seasonal cooling efficiency varies by capacity, with a value of up to 18.3 SEER2. The CPSC2 reaches up to 8.6 for certain models.

The product line is also identified as compliant with:

• ENERGY STAR 6.1;
• ENERGY STAR Cold Climate.

These certifications may be relevant when evaluating certain financial incentives. Actual eligibility depends on the exact unit pairing, the applicable reference number, the program in effect, and the building-specific conditions.

Therefore, it is not enough for the product line name to appear in a brochure. The indoor and outdoor models must form an officially recognized combination.

The thermostat and control logic

The manufacturer offers two compatible control options, including a touchscreen thermostat and a wired controller, both of which may offer Wi-Fi features depending on the configuration.

The thermostat must properly manage:

• heating demand;
• cooling demand;
• ventilation;
• supplementary electric heating;
• emergency mode;
• defrost sequences;
• temperature settings;
• operating delays.

An incorrect configuration can cause the electrical components to operate too frequently or prevent the system from modulating as intended.

Mistakes to avoid in a cramped mechanical room

Installing the unit without checking filter access

Filter replacement is a routine task. If a partition or duct blocks access, maintenance will be neglected.

Placing wires in front of the panels

Connections must be grouped and secured to allow panel removal without having to cut or move the wiring.

Compressing the drain against the structure

The drain must maintain a natural slope and remain accessible.

Reducing the duct transition excessively

A transition that is too small can restrict airflow and increase noise.

Neglecting side clearance

Even when the unit appears to fit in the space, certain components may require side access depending on the model.

Choosing capacity solely based on the old unit

An older system may have been oversized or poorly suited to the building. Replacement should be based on the building’s current needs.

What the homeowner should monitor after commissioning

Once the system is operating, the homeowner should regularly check:

• the condition of the filter;
• water near the unit;
• unusual noises;
• temperature differences between rooms;
• how often the supplemental heating operates;
• messages displayed on the thermostat;
• vibrations in the ducts;
• circuit-breaker trips.

The filter should be replaced according to its type and the conditions in the home. A house with pets, renovations, or a lot of dust may require more frequent checks.

Return grilles must remain unobstructed. Blocking a large grille with furniture can significantly reduce airflow and affect the entire system.

An ELIOS installation designed around Otterburn Park’s real-world constraints

This ELIOS Central-Elios R-454B-compatible electric furnace installation in Otterburn Park illustrates an essential aspect of HVAC work: the equipment must be adapted to the building, not the other way around.

In this basement, the indoor unit had to be installed in a very limited mechanical corridor, between an existing duct network and a wooden structure. Every inch mattered. We had to consider the cabinet dimensions, access to the panels, drainage, refrigerant connections, and future circulation around the equipment.

Heat pump technology, low-temperature performance, and energy efficiency are important. However, everyday comfort also depends on less visible details: static pressure, duct sealing, the capacity of the electrical heating elements, fan settings, and thermostat configuration.

At AirGreen, we apply this same rigor to our electric furnace, central heat pump, heating, and air conditioning projects in Montreal, Laval, Longueuil, the North Shore, and the South Shore. A well-planned installation facilitates not only the system’s immediate operation, but also its maintenance throughout its service life.