A rooftop HVAC project where every detail matters
In Chomedey, a dense and active sector of Laval, AirGreen completed a specialized HVAC installation featuring a GREE Mini-GMV VRF system designed to meet multi-zone comfort needs, with a much more technical approach than a standard residential wall-mounted heat pump or wall air conditioner installation. In the site photo, the work environment is clearly visible: two outdoor units installed on a sturdy wooden base, a flat roof with membrane, an open service panel for internal checks, manifolds, insulated refrigerant lines, as well as a nitrogen tank used during the testing and validation stages of the circuit.
This type of installation requires precise planning. Unlike a simple wall system, a VRF distributes heating and cooling capacity to multiple zones, with modulating refrigerant flow management. The desired result is not just to heat or cool a space, but to maintain thermal stability in different rooms, with optimized consumption and reliable performance during the demanding seasons of Greater Montreal.
Why choose a GREE Mini-GMV VRF in Chomedey?
The choice of a GREE Mini-GMV is explained by the nature of the building and the client's expectations: multiple spaces to be treated, roofing constraints, a need for heating performance, and a desire to obtain a centralized solution without unnecessarily multiplying outdoor equipment. In an area like Chomedey, where residential, commercial, and mixed-use buildings are found, VRF systems become particularly relevant when a project requires fine management of multiple zones.
The GREE Mini-GMV platforms are designed for larger-scale installations than traditional wall-mounted systems. They allow multiple indoor units to be powered from the same outdoor unit, with a control logic adapted to the building's actual needs. Depending on the chosen configuration, GREE VRF systems can be offered with compressors of 36,000 BTU or 48,000 BTU, in multi-zone versions, for example 2, 3, 4, 5, 6, or 7 zones depending on the project. In Chomedey, this flexibility was at the heart of our analysis.
A rooftop installation: stability, clearance, and building protection
One of the most important aspects of this site was the installation of outdoor units on the roof. A flat roof often offers an excellent location for a VRF system, but only if the installation meets several technical criteria.
We paid special attention to:
- weight distribution on a stable base;
- clearance around the units to ensure good air circulation;
- the protection of the roofing membrane;
- future accessibility for HVAC maintenance;
- the neat routing of refrigeration lines;
- the reduction of vibrations transmitted to the structure;
- the compliance of electrical and refrigeration connections.
The wooden base visible in the photo was not improvised. It raises the equipment, creates a solid support, facilitates drainage around the units, and maintains a safe distance between the machines and the roof surface. For a system installed in Laval, where snow, frost, freezing rain, and thaw episodes can follow each other quickly, this detail becomes essential for durability.
Commissioning a VRF system: tests, pressure, nitrogen, and performance validation
The most critical phase of a GREE VRF project is not just the physical installation of the equipment. The true quality of the work is confirmed at the commissioning stage. On this site in Chomedey, our technicians carried out a series of checks before the system's final start-up.
The importance of the nitrogen test
The cylinder visible in the foreground is part of a fundamental step: the nitrogen pressure test. This test is used to confirm the tightness of the refrigeration network before commissioning. In a VRF installation, where pipe lengths can be longer and branches more numerous than in a simple wall system, this step is essential.
A minor leak can cause:
- a gradual decline in performance;
- operational errors;
- premature compressor wear;
- a loss of comfort in certain areas;
- avoidable service calls;
- additional costs for the owner.
At AirGreen, we handle this step rigorously. Connections, fittings, pipe lengths, insulation, and junction points are checked before moving on to the next steps. It is precisely this kind of discipline that distinguishes a durable HVAC installation from a simply functional short-term job.
An open service panel for a complete inspection
In the image, you can also see the technical panel open on the outdoor unit. This detail illustrates a common but essential step: checking internal components, electrical connections, the control board, terminal blocks, communication wiring, and elements related to the refrigeration circuit.
A VRF system relies on constant communication between the outdoor unit and indoor units. A wiring error, incorrect zone assignment, or incomplete configuration can impair overall operation. Our team therefore validates the system logic before final delivery to the client.
R-410A refrigerant and heating performance down to -30 °C
The GREE Mini-GMV systems presented in this range use R-410A and are designed to provide heating capacity suited to Quebec winters, with performance rated down to -30 °C depending on models and configurations. For a building located in Chomedey, this capacity is a major advantage, as temperature variations between January, March, and thaw periods can challenge less well-adapted systems.
Choosing the right equipment is not limited to the number of BTUs. You must consider:
The actual building load
A glazed space, a commercial area with heavy foot traffic, an upper floor exposed to the sun, or a north-facing room do not have the same needs. For a VRF system, sizing must take each zone into account.
Pipe lengths
A multi-zone system may require longer routes, especially when indoor units are spread across several spaces. The planning of refrigerant lines directly influences performance.
Maintenance access
A rooftop installation must be planned for the future. Technicians must be able to access the units without excessive difficulty for HVAC maintenance, seasonal checks, and diagnostics.
Condensate management
Each indoor unit must properly drain condensation. In some projects, this involves precise slopes, drainage pumps, or a specific routing to avoid backflows and damage.
Mistakes to avoid with a VRF system
A VRF GREE is an excellent solution when well designed and properly installed. However, several mistakes can compromise the result.
The first mistake is choosing capacity solely based on area. In Greater Montreal, and particularly in areas like Montreal, Laval, Longueuil, the North Shore and the South Shore, two buildings of the same size can have very different thermal loads depending on insulation, orientation, windows, and actual use of the spaces.
The second mistake is neglecting coordination between zones. A VRF system must be considered as a whole. If one zone is oversized and another undersized, comfort becomes uneven.
The third mistake concerns the roof. Installing a unit without an adequate base, without membrane protection, or without sufficient clearance can create problems with noise, drainage, service, and durability.
The fourth mistake is to entrust the commissioning to a team that is not used to complex multi-zone systems. The VRF requires knowledge in refrigeration, control, communication, pressure, drainage, and diagnostics.
A project carried out with a long-term logic
In Chomedey, our goal was not just to complete the installation quickly. We worked with a long-term reliability mindset. The roof was protected, units were positioned to facilitate service, connections were validated, pressures were tested, and commissioning was carried out methodically.
This approach is especially important for building owners and managers. A VRF system represents a more strategic investment than a simple equipment replacement. It must provide consistent comfort, reduce unnecessary interventions, and enable efficient space management.
AirGreen as a GREE Elite dealer
AirGreen regularly works with GREE equipment, notably for high-end residential, commercial, and multi-zone projects. Our experience as a GREE Elite dealer allows us to support clients on multiple levels: configuration selection, zone analysis, choice of indoor units, validation of roof constraints, installation, programming, and after-sales service.
For selected GREE models, certain configurations may benefit from a warranty of up to 12 years, depending on applicable conditions. This protection is especially relevant for large-scale installations where operational continuity is as important as comfort.
Subsidies and eligibility: a case-by-case verification
For VRF systems, eligibility for subsidies strongly depends on the type of building, configuration, current program, equipment efficiency, and required documents. Unlike some residential wall-mounted heat pumps clearly listed in programs like LogisVert, a VRF project must be analyzed more precisely.
At AirGreen, we help our clients verify applicable options before making a final recommendation. We avoid vague promises: the right approach is to validate the program criteria, model numbers, technical documents, the invoice, and the building context.
Expertise available in Montreal, Laval, Longueuil, North Shore, and South Shore
This project in Chomedey reflects the type of work we regularly carry out in Greater Montreal. In Montreal, we often work in buildings where access is restricted, where condominiums impose precise rules, and where the visual discretion of equipment is important. In Laval, multi-residential and commercial projects often require more flexible systems. In Longueuil, on the South Shore and on the North Shore, constraints vary between single-family homes, income properties, offices, shops, and mixed-use buildings.
Our role is to propose a realistic, durable, and well-explained solution. For an owner, this means understanding why a VRF is recommended, how the zones will be served, where the units will be installed, how maintenance will be performed, and what comfort results to expect.
The result: a clean, accessible system ready for Quebec seasons
At the end of this installation in Chomedey, the GREE Mini-GMV system was positioned on a sturdy base, with accessible connections and a complete technical commissioning. The client now benefits from a VRF solution adapted for multi-zone management, designed to provide precise heating and cooling.
The real success of a project like this is not measured only at the equipment start-up. It is measured in the months that follow: stable comfort, quiet operation, easy access for maintenance, no surprises, and consistent performance when the outdoor temperature becomes more demanding.
This is exactly the approach we apply at AirGreen: clear recommendations, meticulous execution, transparency in the steps, and after-sales service capable of supporting technical installations. For a GREE VRF system in Chomedey, in Laval, in Montreal, in Longueuil, on the North Shore or on the South Shore, every detail of design and commissioning matters.