A precise central conversion in a masonry mechanical room
At Varennes, we installed an ELIOS electric furnace compatible with a central heat pump using R454B refrigerant in a basement mechanical room where every connection had to be adapted to an existing configuration. The indoor unit visible in the photograph bears model number EAHMA36R4AS1, corresponding to the 36,000 BTU ELIOS central combination.
This detail is important: it allows us to go beyond a simple general description of the project. We can identify a 36,000 BTU central indoor unit designed to operate with the ESHMB36R2AN1 outdoor model from the Central-Elios range. This combination uses R454B, Inverter technology, and a design intended for heating in cold climates.
The project took place in a typical setting for several older homes in Varennes and the South Shore: stone or masonry foundation walls, a duct network built around an older appliance, existing piping, limited side clearance, and the immediate proximity of other mechanical equipment.
We therefore had to install the new unit in a way that preserved four essential elements:
- proper airflow;
- access to the service panels;
- reliable condensate drainage;
- clean integration with the existing ductwork.
The result is a compact and technically coherent central HVAC installation, without sacrificing the access required for future maintenance.
A clearly identifiable 36,000 BTU ELIOS indoor unit
The visible plate on the front indicates the indoor model EAHMA36R4AS1. According to Central-Elios technical documentation, this unit is paired with the outdoor model ESHMB36R2AN1 in the 36,000 BTU configuration.
For this combination, the documentation indicates in particular:
- a rated cooling capacity of 36,000 BTU/h;
- a cooling modulation range of 9,700 to 42,000 BTU/h;
- a rated heating capacity of 37,000 BTU/h;
- a heating range of 11,000 to 48,000 BTU/h;
- a SEER2 of 17.3;
- a TE2 of 11.7;
- a CPSC2 of 8.6 in Region V;
- a coefficient of performance of 3.6 at 8.3 °C;
- an ENERGY STAR 6.1 – cold climate certification;
- a heating operating range down to −30 °C.
These values describe the complete combination of the indoor unit and outdoor condenser. They should not be attributed to the furnace alone, since performance results from matching the two components.
Why a 36,000 BTU capacity should not be chosen based solely on square footage
A 36,000 BTU central heat pump, often associated with a capacity of approximately three tons, should not be selected solely based on the home’s square footage.
In Varennes, as elsewhere in Montreal, Laval, Longueuil, on the North Shore and the South Shore, two properties of the same size may have very different needs. Several factors affect the actual load:
- year of construction;
- insulation level;
- air infiltration;
- the number and type of windows;
- the home’s orientation;
- number of floors;
- basement area;
- ceiling height;
- exposure to wind;
- the condition of the ductwork.
An oversized unit can reach the requested temperature too quickly and operate in short cycles. In cooling mode, this can reduce the time available to remove moisture from the air.
Conversely, a unit that is too small may run for long periods during the coldest weather without maintaining the desired temperature.
At AirGreen, we therefore analyze the building, air distribution, and electrical capacity before confirming the system size.
A replacement carried out near an old unit
The photograph shows that old equipment remains visible to the left of the new unit. This situation highlights one of the project’s main constraints: the new furnace had to be installed in an area that was already very crowded.
In an existing mechanical room, positioning the new unit depends on more than just its width. The following must also be considered:
- the complete opening of the panels;
- the routing of the refrigerant lines;
- access to the electrical connections;
- the drain routing;
- the fabrication of the duct transitions;
- the removal or possible modification of the old unit;
- the space needed by future technicians.
We positioned the unit vertically while keeping its front fully accessible. This orientation allows the main components to be reached without having to dismantle the ductwork.
A large furnace despite its compact integration
For the 36,000 BTU capacity, the documentation indicates that the indoor unit measures approximately:
- 21.02 in. wide;
- 21.02 in. deep;
- 49.02 in. high;
- for a net weight of approximately 129.41 lb.
These dimensions explain why preparing the space is essential. A unit may seem compact in a photo, but transporting, positioning, and connecting it require sufficient working clearance.
An upper plenum built for the existing ductwork
The top of the furnace is connected to a metal plenum. This plenum acts as a distribution chamber before the air is sent through the ductwork.
For this project, we had to adapt the transition to the geometry of the existing upper duct. A poorly designed transition can create a restriction or excessive turbulence.
Possible consequences include:
- high static pressure;
- increased air noise;
- reduced airflow;
- uneven comfort between rooms;
- increased ventilation motor consumption;
- reduced system performance.
A well-made transition allows the airflow to change direction or size more gradually.
Why the airflow direction is clearly identified
On the right-side duct, an arrow labeled « AIR » shows the direction of airflow. This simple marking is useful during installation and future service work.
It allows you to quickly identify:
- the return side;
- the direction of airflow through the filter;
- the direction toward the unit;
- the orientation of the accessories;
- the overall system layout.
A filter installed backward, for example, may become deformed or operate less efficiently. The direction indicated on its frame must correspond to the airflow toward the furnace.
The importance of the return air and central filter
The cabinet located to the right of the unit includes an access panel for filtration. This section brings air from the house back to the furnace for treatment.
In many central replacement projects, the return air is the weak point of the system. A new heat pump may offer excellent specifications, but it cannot deliver its expected performance if it lacks sufficient airflow.
An overly restrictive return can cause:
- whistling;
- an abnormal air temperature;
- reduced airflow at the registers;
- excessive strain on the fan;
- a risk of the coil freezing in cooling mode;
- overheating during electric heating;
- an increase in noise in the mechanical room.
The filter must also be suitable for the system. A highly restrictive filter is not automatically better. Its size, thickness, and filtration level must be compatible with the required flow rate.
Carefully insulated refrigerant lines
To the left of the unit, the refrigerant lines are covered with black insulation. They connect the indoor coil to the condenser installed outdoors.
For the 36,000 BTU ELIOS combination, the documentation specifies:
- a liquid line of 3/8 po;
- a gas line of 3/4 po;
- a maximum piping length of 246 pi;
- a maximum height difference of 98,4 pi.
These limits do not mean that it is desirable to systematically install very long lines. They indicate the maximums permitted by the system design.
In an actual installation, we seek a route that is as direct as reasonably possible. Each additional length can affect the refrigerant charge, thermal losses, and project complexity.
Why Insulation Must Remain Continuous
The gas line must be properly insulated. Open, crushed, or discontinuous insulation can cause condensation and performance losses.
In a basement, this condensation can wet:
- the floor;
- the ducts;
- the foundation wall;
- the wires;
- nearby components.
We therefore inspect the insulation joints and the areas where the lines change direction.
R454B and the A2L label visible on the appliance
The unit is clearly labeled A2L, associated with the use of R454B.
R454B is a mildly flammable refrigerant. This property requires more precise handling rules than some previous refrigerants.
The manufacturer incorporates, among other things, a safety system designed to monitor leaks. The documentation specifies that if a leak is detected, the system can stop the compressor, maintain ventilation, and generate a service alert.
For the occupant, operation remains simple. The precautions mainly concern installation, repair, and refrigerant recovery.
Technicians must use:
- appropriate detection equipment;
- compatible tools;
- a rigorous evacuation procedure;
- a compliant charging method;
- practices suitable for R454B;
- adequate ventilation of the work area.
An accessible condensate drain equipped with a trap
At the bottom of the appliance, we see a PVC piping assembly and a transparent trap. This component helps control the drainage of condensation produced during air conditioning.
When humid air passes over the cold coil, water forms and drips into the drain pan. This water must leave the unit without backing up.
The trap helps maintain proper drainage according to the pressure inside the unit. Its transparent section also facilitates visual inspection.
Common drainage problems to avoid
An improperly designed drain can cause:
- an overflowing pan;
- water on the floor;
- odours;
- safety shutdowns;
- damage in the mechanical room;
- an accumulation of deposits.
The red plug visible on the connection provides convenient access for inspection or cleaning. This access is useful during HVAC maintenance, since the drain can accumulate dust and residue.
Inverter technology adapted to variable loads
The ELIOS central heat pump uses an Inverter compressor. This technology allows the outdoor unit to modulate its output rather than operating only at full capacity.
The 36,000 BTU combination can reduce its cooling capacity to approximately 9,700 BTU/h and increase it to 42,000 BTU/h, depending on conditions. In heating mode, its stated range extends from approximately 11,000 to 48,000 BTU/h.
This modulation provides:
- longer cycles;
- more stable temperature;
- better adaptation to periods of low demand;
- fewer abrupt starts;
- generally quieter operation;
- energy consumption better aligned with the building’s needs.
On a mild day, the system can operate at a low output. When a cold snap arrives in Varennes, it can increase its capacity according to demand.
A system designed for Quebec’s cold climate
The Central-Elios combination operates in heating mode down to −30 °C. The line is advertised as maintaining up to 100% of its rated capacity at −20 °C, then approximately 69% to 76% of its rated capacity at −30 °C, depending on the capacity.
This distinction is important. A heat pump can continue operating at a given temperature without necessarily producing its full rated capacity.
The selection of supplemental electric heating elements must therefore take into account:
- the home’s heat loss;
- the heat pump’s low-temperature capacity;
- the balance point;
- the available electrical capacity;
- the occupants’ temperature habits.
The role of auxiliary electric heating
The Central-Elios line can accommodate optional electric heating coils from 3 to 25 kW.
In a residence in Varennes, this auxiliary heating can operate when:
- the outdoor temperature becomes very low;
- the house requires a rapid temperature increase;
- the heat pump is defrosting;
- demand temporarily exceeds the available capacity;
- the outdoor system is out of service.
The supplementary heating capacity must not be selected without checking the electrical panel. A more powerful element requires appropriately sized conductors and protection.
We therefore coordinate the mechanical and electrical configuration before commissioning.
The essential checks performed on this installation in Varennes
Airflow check
We check that the blower is configured for the three-ton capacity and the home's actual ductwork.
A setting that is too high can increase noise. A setting that is too low can impair heat exchange and dehumidification.
Static pressure validation
Static pressure helps assess the resistance created by the ductwork, filter, transitions, and registers.
Excessive pressure may indicate:
- an overly restrictive filter;
- an undersized return;
- a crushed duct;
- too many closed registers;
- an improperly sized transition;
- a blocked coil.
Drain inspection
We test drainage and inspect the connections. The trap must be installed in the correct orientation and remain accessible.
Refrigerant system check
After the leak test, the circuit must be evacuated to remove air and moisture. The charge is then checked according to the manufacturer's requirements and the actual length of the lines.
Supplementary heating test
The electric heating stages must activate according to the thermostat command and the selected programming. Activating them too frequently could unnecessarily increase consumption.
Noise and vibration inspection
The proximity of metal ducts and the foundation wall can promote sound transmission. We check that no duct or panel is vibrating against another surface.
Practical advice for Varennes homeowners
Do not close several registers to save energy
Closing too many air outlets increases pressure in the ductwork and may reduce airflow through the furnace.
The central system must operate with balanced distribution. Any significant modification should be evaluated rather than carried out at random.
Inspect the filter regularly
A dirty filter can quickly affect the performance of a central unit.
Replacement frequency depends on:
- filter type;
- the presence of pets;
- renovation work;
- dust;
- the number of occupants;
- fan usage.
Keep the drain accessible
The trap and cleanout plug must not be hidden behind stored items. Clear access speeds up maintenance and makes it possible to identify water accumulation.
Do not use performance values without verifying the combination
The TRÉS2, CPSC2, and ENERGY STAR values apply to specific pairings of the indoor and outdoor units.
In this project, the identified indoor unit is the EAHMA36R4AS1. The documented combination uses the outdoor model ESHMB36R2AN1. This is the combination that must be used to verify performance and eligibility for a rebate.
Rebates: validation required before installation
The documentation indicates that the 36,000 BTU combination is certified ENERGY STAR 6.1 cold climate. This certification may be relevant to certain programs, but it does not by itself guarantee financial assistance.
Eligibility depends in particular on:
- the program in effect;
- the type of building;
- the previous system;
- the exact model combination;
- the work completed;
- the installation date;
- the documents provided;
- the applicable official list.
We always recommend checking the file before ordering and keeping:
- the detailed invoice;
- serial numbers;
- model numbers;
- photos of the nameplates;
- proof of payment;
- the commissioning documents.
A representative example of our work on central systems
This 36,000 BTU ELIOS R454B electric furnace installation in Varennes perfectly illustrates the difference between simply installing an appliance and fully integrating a central system.
We had to take into account:
- the existing masonry;
- the space between the old equipment;
- the position of the duct network;
- the direction of the return air;
- filter access;
- the refrigerant lines;
- drainage;
- the safety considerations associated with R454B;
- future maintenance.
The unit is accessible from the front, the drain can be inspected, the lines are insulated, and the upper connection joins the existing network cleanly.
At AirGreen, we install electric furnaces, central heat pumps, and HVAC systems in Varennes, Boucherville, Sainte-Julie, Longueuil, Beloeil, and Saint-Bruno-de-Montarville, as well as in Montréal, Laval, the North Shore, and throughout the South Shore.
The actual performance of a 36,000 BTU system depends not only on its technical specifications. It also relies on sizing, airflow, ductwork, drainage, refrigerant charge, and the quality of the commissioning.
In this Varennes project, every visible detail in the mechanical room contributes to the final result: a well-structured central system, adapted to the building and ready to provide heating and cooling for the residence throughout all four seasons.