A complex central integration in a narrow mechanical room that was already heavily occupied
This installation of an ELIOS electric furnace compatible with a central heat pump using R454B, carried out in Saint-Mathieu-de-Beloeil, represents exactly the type of project in which the quality of the work depends not only on the equipment selected. It relies above all on the ability to integrate a new unit into an existing environment, with its ducts, wooden structures, accessories, refrigerant-line routes, and access constraints.
The photograph shows a particularly compact mechanical room. The new ELIOS indoor unit was installed between a wooden frame, an old air-distribution plenum, several flexible ducts, and existing connections. This was therefore not an installation carried out in an open basement, where each component could be positioned freely.
Our work consisted of adapting the new central system to the reality of the home while preserving:
- adequate airflow;
- access to the service panels;
- coil drainage;
- protection of the refrigerant lines;
- the furnace’s mechanical stability;
- compatibility with the ductwork;
- sufficient space for future HVAC maintenance.
In this type of project, an installation may appear functional at first glance while concealing airflow restrictions, poorly supported ducts, or inaccessible components. We must therefore consider not only the system’s immediate start-up, but also how it will perform over the following years.
An ELIOS electric furnace installed at the heart of the central system
The indoor unit shown in the photo is the component that circulates air throughout the house. It is connected to an outdoor heat pump and works with a central coil to provide heating and cooling.
In a home equipped with ductwork, the electric furnace never operates in isolation. It is part of a system that includes, among other things:
- outdoor heat pump;
- indoor coil;
- variable-speed fan;
- supplementary electrical components;
- the thermostat or controller;
- filter;
- supply and return ducts;
- condensate drainage;
- refrigerant lines;
- the detection and safety devices.
The technical documentation for the Central-Elios system indicates that the range is offered in nominal capacities of 24,000, 30,000, 36,000, 48,000, and 60,000 BTU, with indoor units suited to each combination. The document also specifies that these systems use R454B refrigerant, are certified ENERGY STAR V6.1 Cold Climate, and can operate in heating mode down to an outdoor temperature of -30 °C.
The exact capacity installed in Saint-Mathieu-de-Beloeil must nevertheless be confirmed using the complete model number. A general photograph cannot reliably verify the tonnage, auxiliary electrical capacity, or AHRI number of the combination.
The main challenge: preserving airflow despite the obstacles
The visible ductwork around the unit includes several sections of rigid and flexible ducts. On the right, a large flexible duct passes very close to the furnace before connecting to a metal section. The proximity of the equipment required particular care to avoid crushing, pinching, or excessively bending this duct.
A restriction in a return or supply duct can lead to several consequences:
- reduced airflow at the registers;
- increased noise;
- overheating of the electrical elements;
- reduced heating capacity;
- reduced cooling efficiency;
- excessively high static pressure;
- extended blower operation;
- premature motor wear.
In a central HVAC installation, airflow is just as important as the equipment's capacity. A quality furnace cannot deliver its full performance if air flows through ducts that are too small, obstructed, or improperly connected.
We must therefore examine the complete ductwork layout: return dimensions, transition to the furnace, filter, elbows, branches, and condition of the flexible ducts. The new unit must be installed to meet the airflow requirements of the heat pump and coil.
A metal base adapted to the available space
The ELIOS unit sits on a metal plenum that serves as a base, transition, and connection to the existing ductwork. This custom-made component is essential for aligning the furnace with the home's ducts.
An improperly sized lower plenum could cause irregular airflow into the blower. A transition that is too abrupt could also increase turbulence and noise.
The base must perform several functions:
- support the weight of the unit;
- keep the furnace upright and stable;
- ensure an airtight transition;
- distribute air evenly;
- avoid vibrations;
- maintain access to the lower panels.
In the photo, the refrigerant lines run along the lower part of the unit. We therefore also had to position the base to allow the copper and insulation to pass through without placing excessive strain on the fittings.
Protected and properly routed refrigerant lines
The larger-diameter line is covered with black insulation. This insulation protects the suction line from heat gain and condensation.
In cooling mode, this line can become cold. Without adequate insulation, moisture in the basement air could condense directly on the copper and then drip onto the cabinet or floor.
We pay particular attention to the following points:
- continuity of the insulation;
- absence of exposed copper;
- bend radius;
- mechanical support;
- protection against chafing;
- absence of strain on the fittings;
- tightness of the connections;
- compatibility of the diameter with the model.
According to the Central-Elios technical data sheet, the different capacities in this range use a 3/8 in liquid line and a 3/4 in gas line. The specified maximum lengths range from 164 ft to 246 ft, depending on system capacity, with a maximum elevation difference ranging from 82 ft to 98.4 ft.
These values do not mean that every installation must use the maximum length. Rather, they define the technical limits for each combination. A longer route may require charge adjustments and a precise commissioning procedure.
Coil drainage: essential protection
The visible PVC pipes at the bottom of the unit are used to drain condensation water. This water is produced when the system operates in cooling mode and moisture in the air condenses on the indoor coil.
Poorly designed drainage can cause:
- a water leak;
- accumulation beneath the furnace;
- damage to nearby wood;
- corrosion;
- odors;
- a blockage caused by deposits;
- a safety shutdown;
- an increase in humidity in the mechanical room.
In this installation in Saint-Mathieu-de-Beloeil, the space around the drain was limited. We therefore had to plan the route to allow drainage while maintaining access for inspection and cleaning.
The manufacturer's data sheet indicates that the dehumidification capacity of the range varies according to system size, from 2.05 L/h to 5.87 L/h under the stated test conditions. This figure highlights that a central heat pump can produce a significant amount of condensate during hot and humid periods.
The Central-Elios R454B system: winter performance, modulation, and responsible installation
A heat pump designed for Quebec's cold climate
The Central-Elios system is designed to maintain heating in demanding winter conditions. The documentation indicates a capacity of up to 100% of nominal capacity at -20 °C, as well as a capacity corresponding to approximately 69% to 76% of nominal capacity at -30 °C, depending on the model and the conditions specified by the manufacturer.
This feature is particularly relevant for a residence located in Saint-Mathieu-de-Beloeil, where winter temperatures can place a significant load on the system.
The heat pump transfers heat from the outdoor air indoors. As the temperature drops, its capacity and coefficient of performance change. The furnace's electric elements can then provide additional support when the home's heating needs temporarily exceed the heat pump's capacity.
The manufacturer offers supplemental electric heating coils ranging from 3 to 25 kW. The appropriate capacity must be selected according to:
- the home's heat losses;
- the heat pump's low-temperature capacity;
- the electrical panel;
- the available circuit;
- airflow;
- the control strategy;
- applicable local requirements.
Automatically installing the largest electrical element is not good practice. Excessive capacity can place an unnecessary load on the electrical panel and lead to high energy consumption. Insufficient capacity may fail to maintain comfort during the coldest periods.
Inverter technology to prevent abrupt cycling
The Central-Elios range uses Inverter technology, allowing the compressor to modulate its speed according to actual needs.
Instead of operating only at full capacity and then shutting off, the system can gradually reduce or increase its output. This modulation helps to:
- stabilize the indoor temperature;
- reduce short cycling;
- limit comfort fluctuations;
- reduce certain startup noises;
- improve operation during the shoulder seasons;
- adapt consumption to demand.
The documentation indicates efficiencies of up to 18.3 TRÉS2, as well as a CPSC2 of up to 8.6, depending on the combination. The models in the range also have TRÉ2 cooling efficiencies ranging from 10 to 11.7.
However, actual performance in a home depends on many factors: sizing, duct tightness, airflow, thermostat programming, outdoor temperature, insulation, and quality of commissioning.
R454B and integrated leak detection
R454B is a next-generation refrigerant with lower global warming potential than R410A. Its use requires compatible equipment and appropriate procedures.
Central-Elios documentation specifies that the system includes an integrated leak detection sensor. If an abnormal condition occurs, this device can stop the compressor, maintain air circulation, and generate a service alert.
This technology does not replace an airtight installation. It is an additional safety measure.
During commissioning, we must in particular perform:
- leak test;
- checking the connections;
- vacuum evacuation;
- charge validation;
- checking the controls;
- testing of safety devices;
- confirmation of airflow;
- validation of auxiliary heating.
A system can start even if some settings are incorrect. That is why commissioning must never be limited to turning on the thermostat and observing that air is coming out of the registers.
A relatively compact indoor unit, but not interchangeable
The indoor unit’s dimensions vary according to capacity. The technical data sheet indicates, among other things:
- 24,000 BTU: 17.52 × 21.02 × 45 in;
- 30,000 and 36,000 BTU: 21.02 × 21.02 × 49.02 in;
- 48,000 and 60,000 BTU: 24.49 × 21.02 × 52.99 in.
These differences are considerable when an installation must be carried out in a tight space like the one shown in the photo.
Before ordering the unit, we therefore need to measure:
- clear height;
- width between obstacles;
- available depth;
- front access;
- clearance for the filter;
- the passage for the lines;
- the opening required to remove the fan;
- the height of the lower cabinet.
An error of a few inches can require rebuilding a significant section of the ductwork.
What we check before completing a central installation
Once the equipment is installed, we carry out several mechanical, electrical, and refrigeration checks.
Air side
We check:
- airflow direction;
- transition airtightness;
- fan speed;
- filter;
- discharge and return air temperatures;
- turbulence noises;
- static pressure when necessary.
Refrigeration side
We check:
- connections;
- insulation;
- charge;
- temperatures;
- compressor operation;
- the system’s response to commands.
Electric heating side
We inspect:
- current;
- electrical protections;
- stage activation;
- the sequence with the heat pump;
- discharge air temperature;
- thermostat programming.
Drainage side
We confirm:
- the slope;
- drainage;
- airtightness;
- cleaning access;
- the absence of a discharge outlet.
The most common mistakes in a compact mechanical room
This installation in Saint-Mathieu-de-Beloeil highlights several mistakes homeowners should avoid when replacing an electric furnace:
- selecting the equipment without measuring the room;
- placing a flexible duct against a service panel;
- reducing the return-air size to facilitate installation;
- using a sheet-metal transition that is too narrow;
- making the filter inaccessible;
- leaving a section of copper uninsulated;
- installing a drain without cleaning access;
- overlooking the building's electrical capacity;
- combining uncertified components;
- assuming that the old unit's tonnage is automatically adequate.
Replacing a central system should begin with an analysis of the home, not simply by reading the nameplate on the old unit.
Eligibility for financial assistance: verify the complete combination
The Central-Elios line is identified as ENERGY STAR V6.1 cold climate in the manufacturer's documentation. This is a favorable factor when assessing certain financial assistance programs.
However, eligibility cannot be confirmed solely based on the brand or the presence of the ENERGY STAR logo. The following generally needs to be verified:
- the indoor model;
- the outdoor model;
- the certified combination;
- the AHRI number;
- the recognized capacity;
- the purchase date;
- the program criteria;
- the type of building;
- proof of installation.
We therefore verify the exact references before presenting a potential amount to the property owner.
An installation adapted to the building rather than an imposed solution
The project completed in Saint-Mathieu-de-Beloeil demonstrates that a successful central installation relies on a series of precise decisions: furnace placement, transition geometry, copper routing, drainage, front access, and airflow protection.
In this mechanical room, we had to work around existing elements without compromising the new system's functionality. The result is an ELIOS R454B electric furnace integrated into a tight space, connected to the central ductwork, and accessible for maintenance.
At AirGreen, we install electric furnaces, central heat pumps, and HVAC systems in Saint-Mathieu-de-Beloeil, Longueuil, on the South Shore, as well as in Montreal, Laval, and on the North Shore. We assess each home based on its actual layout so that the equipment, ductwork, and controls operate as one cohesive system.