Installation of a 2-head GREE Free Match R32 heat pump in Saint-Polycarpe, in Montérégie

An installation beneath a deck where every clearance mattered

At Saint-Polycarpe, this HVAC installation project had a specific objective: to supply two distinct zones of the building from a single outdoor unit while integrating the new equipment into an already occupied mechanical space. The selected solution, a GREE Free Match R32 2-head heat pump, reduces the number of outdoor appliances without sacrificing comfort control in the rooms served.

The site photograph shows a situation we regularly encounter in Greater Montreal: a concrete foundation, a wooden deck above the work area, an existing appliance nearby, and a relatively narrow corridor for maintenance. In this context, installing a heat pump is not simply a matter of fastening a unit to the wall. We must account for airflow, vibrations, technician clearance, drainage produced during defrost cycles, and coexistence with the other equipment.

The visible result is a clean, structured installation. The GREE unit is installed on metal supports anchored to the foundation, with vibration-damping pads under its contact points. It remains elevated above the ground, its front fan is free of significant obstructions, and the refrigerant connections are grouped on the right side, near the electrical disconnect.

Why use a 2-head heat pump in this type of building

A multi-zone heat pump connects multiple indoor units to a single outdoor compressor. In this Saint-Polycarpe project, two heads serve two spaces whose needs are not necessarily identical.

This configuration may be suitable for:

• a ground floor and an upper floor;
• an open-plan area and a primary bedroom;
• two dwellings or two sections of the same building, depending on the mechanical design;
• an extension that does not receive enough air from a central system;
• two distant rooms that each require their own air distribution.

Each indoor unit can normally have its own temperature setting and fan speed. However, it remains important to explain how a multi-zone system works: both heads share the same outdoor unit and generally need to operate in compatible modes. One head therefore should not be used for heating while the other simultaneously calls for cooling.

This feature is not a problem when the zones have consistent uses, but it must be explained before installation. At AirGreen, we prefer to clarify this reality during the assessment rather than give the impression that a multi-zone heat pump is equivalent to two completely independent systems.

A range designed for multiple indoor unit combinations

The GREE Free Match R32 range includes several outdoor unit capacities. The exact model must be selected based on the building’s heating load and the permitted indoor unit combinations, not solely on the approximate size of the rooms.

The technical data sheet lists the following configurations:

• GWHD(18)ND6MO: nominal capacity of 18,000 BTU/h and connection of two indoor units;
• GWHD(24)ND6MO: nominal capacity of 24,000 BTU/h and connection of two to three units;
• GWHD(30)ND6MO: approximately 28,400 BTU/h in cooling, 30,000 BTU/h in heating, and connection of two to four units;
• GWHD(36)ND6MO: nominal capacity of 36,000 BTU/h and connection of two to four units;
• GWHD(42)ND6MO: nominal capacity of 42,000 BTU/h in cooling, up to 44,300 BTU/h in heating, and connection of two to five units.

The fact that an outdoor unit can accommodate several indoor units does not mean that all capacity combinations are permitted. The indoor models, their respective BTU ratings, and the total connected capacity must comply with the manufacturer’s combination tables.

The exact capacity is never chosen based on the unit’s appearance

Two outdoor units may look almost identical while having different electrical and refrigeration characteristics. We therefore never determine sizing simply by looking at the enclosure size.

Our selection takes several factors into account:

1. heat loss from each zone;
2. wall and roof insulation;
3. the size and orientation of the windows;
4. ceiling height;
5. exposure to wind;
6. the natural distribution of air between rooms;
7. the actual use of each zone;
8. the system’s minimum modulation capacity.

An oversized unit can quickly reach its set temperature, shut off too early, and reduce dehumidification quality in summer. An undersized unit may run continuously during cold periods without reaching the expected comfort level. The right choice lies between these two extremes.

Energy efficiency and operation in cold weather

According to the technical documentation provided, the GREE Free Match R32 can reach up to 21 SEER2, 12.5 EER2, and 10 HSPF2. The advertised operating range extends from -30 °C to 48 °C in cooling and from -30 °C to 24 °C in heating. The maximum total piping length can reach 100 metres on the largest models in the range.

These values are particularly relevant in Quebec. A heat pump installed in Saint-Polycarpe must be able to handle sustained cold spells, rapid temperature changes, and periods of humidity that promote frost formation on the outdoor coil.

The range includes, among other features:

• G10 Inverter compressor technology;
• intelligent defrosting;
• a self-diagnostic function;
• automatic voltage adjustment;
• operation designed to limit noise;
• powering the indoor units from the outdoor unit;
• an A2L refrigerant leak detector.

Inverter technology allows the compressor to modulate its operation instead of working only at full capacity or being off. When demand is low, the system can reduce its speed. When both zones require more heating, it gradually increases its output within the limits of its available capacity.

The role of R32 refrigerant

The marking R32 is clearly visible on the installed unit. This refrigerant belongs to the A2L category, which requires appropriate installation practices, particularly regarding handling, leak detection, ventilation, and commissioning.

In a two-head system, the quality of the refrigerant connections is essential. Each circuit must be prepared precisely to prevent refrigerant loss and moisture ingress.

Our method includes, among other things:

• clean cutting of the copper pipes;
• flaring performed with a suitable tool;
• tightening to the prescribed torque;
• a leak test;
• complete evacuation of the circuit;
• a check of vacuum stability;
• a controlled opening of the service valves;
• a check of the operation of both zones.

The A2L detector announced by GREE is an integrated safety measure, but it never replaces the quality of the piping, fittings, and commissioning.

The technical choices that turn a multi-zone heat pump into a durable installation

A space beneath a deck that was meant to remain ventilated

The underside of a deck can offer some protection from direct precipitation, but it must not become an enclosed space. An outdoor unit moves a considerable volume of air. If the discharged air immediately returns toward the heat exchanger, the system may lose efficiency, increase its operating pressure, and extend its cycles.

On this Saint-Polycarpe job site, the ventilated side of the heat pump was oriented toward the open part of the corridor. This allowed us to avoid directing the air discharge toward the foundation wall or the unit already present on the left.

The framing elements above the unit were also taken into consideration. The wooden joists must not block airflow or prevent access to the top panel when maintenance work is required.

The presence of a second unit changes the planning

The old unit visible on the left reduces the available space and creates a risk of recirculation if the two fans face each other or if their discharge is concentrated in the same passage.

We therefore paid attention to three clearances:

• the front clearance for air discharge;
• the side clearance for connections and servicing;
• the separation between the two units.

This check is particularly important in the narrow yards of Montreal, beneath the balconies of Longueuil, between the closely spaced houses of Laval, and in certain residential areas on the North Shore and South Shore.

Wall-mounted supports to clear the ground

The GREE unit rests on a metal structure secured to the foundation. This method offers several advantages in a Quebec environment:

• it reduces contact with snow and ice;
• it frees the ground for drainage and cleaning;
• it makes access beneath the unit easier;
• it limits the risks associated with a slab shifting;
• it allows the unit’s level to be adjusted precisely.

The visible pads beneath the heat pump’s feet help limit the transmission of vibrations to the supports. This detail becomes important when the unit is installed against a foundation connected to occupied rooms.

A robust support alone is not enough, however. The anchors must be suitable for concrete, the arms must remain level, and their capacity must match the weight of the unit. Depending on the model, the net weight of the Free Match R32 units listed in the specifications ranges from approximately 78 to 174 lb, while the advertised sound pressure level at high speed is between 54 and 63 dB(A).

The actual sound level perceived inside the building also depends on the location, reflective surfaces, vibrations, compressor speed, and distance from bedrooms or windows.

Planning for winter defrost management from the moment of installation

In heating mode, the outdoor coil can accumulate frost. The heat pump then initiates a defrost cycle to melt this buildup. The resulting water must be able to drain freely beneath the unit.

Under a deck, poor management of this water can cause:

• a sheet of ice in the passageway;
• an accumulation beneath the chassis;
• a blockage around the base of the unit;
• splashes on the wall;
• a fall hazard for occupants or the technician.

The elevation visible in the photo facilitates this drainage. It also leaves more room to remove ice when needed without hitting the bottom of the unit.

A common mistake is to install the unit very close to the ground simply because the deck protects it from direct snow. Blowing snow, defrost water, and ice are still present even in a covered space.

Two refrigeration circuits installed with serviceability in mind

The connections run from the right side of the heat pump, in an area where the technician can access the valves and service panel. The insulation protects the gas lines, while grouping the lines reduces clutter around the unit.

The Free Match R32 specifications indicate 1/4 in. liquid lines and 3/8 in. gas lines for the models shown. Depending on the outdoor unit capacity, the maximum permitted height difference ranges from 15 to 25 metres, and the maximum total piping length ranges from 40 to 100 metres. The precharged length also varies by model, which may require adding a calculated amount of refrigerant when the system exceeds the factory charge.

These limits provide some flexibility for positioning the two indoor units, but they should not be interpreted as an invitation to unnecessarily lengthen the lines. A shorter, more direct route generally reduces:

• the amount of materials;
• the number of bends;
• the risk of damage;
• the evacuation time;
• the possible amount of refrigerant to add;
• the losses associated with a poorly planned installation.

A power supply sized according to the model number

The disconnect switch visible to the right of the unit allows the power supply to be locally isolated during maintenance. Its location remains accessible without being installed in front of the fan or behind a hard-to-reach section.

All Free Match R32 units listed in the documentation operate on a 208/230-volt power supply, but their electrical circuits are not identical. Depending on the model, the minimum circuit ampacity ranges from 14.5 to 30 A, while the maximum overcurrent protection ranges from 20 to 45 A.

The circuit breaker and conductor gauge must therefore be selected based on the nameplate of the unit actually installed. We avoid choosing a circuit breaker solely based on the number of BTUs or the apparent size of the enclosure.

An adequate electrical installation includes, in particular:

1. a dedicated circuit;
2. conductors sized according to the unit's requirements;
3. compliant overcurrent protection;
4. an accessible outdoor disconnect switch;
5. continuous grounding;
6. connections protected against moisture;
7. a voltage check before startup.

Commissioning of the two zones

Once the mechanical and electrical work is complete, we validate the behavior of the entire system. A two-head heat pump must be tested as a complete network, not as two separate appliances.

We specifically check:

• the startup of each indoor unit;
• communication between the heads and the outdoor unit;
• response to commands;
• the production of hot and cold air;
• fan operation;
• indoor condensate drainage;
• the absence of abnormal noise or vibration;
• diagnostic codes;
• the condition of the refrigerant connections;
• the air temperature at the intake and outlet;
• operation when both zones simultaneously call for heating or cooling.

This phase also allows us to explain to occupants how to use the two remote controls, how to clean the filters, and how to avoid conflicting settings between the zones.

The mistakes we aim to avoid on a multi-zone installation

Adding up the BTUs without checking the approved combination

Two 12,000 BTU heads do not automatically mean that a 24,000 BTU outdoor unit is suitable for every situation. Available capacity varies according to outdoor temperature, the number of active zones, and the manufacturer-certified pairing.

Block the fan under a deck

A covered structure must not reduce the required clearances. A heat pump installed too far under a balcony may recirculate its own air and lose efficiency.

Neglect access to the valves and electrical panel

A unit can operate correctly while being almost impossible to repair. We plan for future access from the time the supports are positioned.

Forget about the water produced during defrosting

Water does not disappear because the unit is under a deck. It must drain away without forming an accumulation of ice around the support.

Install a circuit breaker based on an estimate

The documentation indicates several electrical protection values depending on the capacity. The complete model and nameplate remain the references.

Exceed the precharged length without adjustment

When the lines exceed the length covered by the factory charge, the amount of refrigerant must be calculated according to the applicable instructions.

Promise simultaneous heating and cooling

Occupants must understand that the heads share a single outdoor circuit. Coordinated operation provides more stable and predictable performance.

Certification, AHRI numbers, and applicable rebates

The range’s technical page provides distinct AHRI numbers for ductless, ducted, and mixed combinations. It also presents the range as ENERGY STAR certified and eligible for certain local rebates.

Actual eligibility must not, however, be confirmed solely based on the name “GREE Free Match R32.” It generally depends on the exact combination, including:

• the outdoor unit model;
• each indoor model;
• the corresponding AHRI number;
• the building type;
• the program rules at the time of the application;
• the purchase and installation documents;
• the required photos and serial numbers.

We therefore keep the equipment’s exact references rather than simply writing “GREE 2-head heat pump” on the documents. This precision facilitates registration, future service, and any applicable reimbursement claim.

The supplied sheet also mentions a standard ten-year warranty, as well as an additional two-year extension from Wolseley when the registration or proof-of-installation requirements are met. The terms must always be validated for the models purchased and the actual project date.

The result obtained in Saint-Polycarpe

This GREE Free Match R32 2-head heat pump installation brings together several details that are not always visible from inside the building:

• a single outdoor unit for two zones;
• an elevated wall-mounted installation;
• anti-vibration mounts;
• preserved front clearance;
• lateral access to the connections;
• planned coexistence with the neighboring unit;
• an accessible electrical disconnect switch;
• a position suited to winter use.

Installing the unit beneath the deck limits the equipment’s visual impact while making use of an area already designated for mechanical equipment. However, the location is effective only because the front of the unit remains unobstructed and the service space has been preserved.

At AirGreen, we apply this same approach to heat pump, wall-mounted air conditioner, and HVAC installation projects carried out in Montreal, Laval, Longueuil, on the North Shore, on the South Shore, and in Montérégie municipalities such as Saint-Polycarpe. The goal is not merely to make the equipment operate on the day of installation. We aim to make the equipment accessible, stable, and suited to the realities of Quebec winters.

Information to require before accepting a quote

To properly compare two multi-zone heat pump proposals, we recommend checking the following:

• the complete model number of the outdoor unit;
• the complete model numbers of both indoor units;
• the rated and minimum capacities;
• the AHRI number for the combination;
• the heating range;
• the SEER2 and HSPF2 efficiency ratings;
• the included piping length;
• the cost of additional piping;
• the wiring gauge and specified circuit breaker;
• the outdoor mounting method;
• condensate and defrost management;
• the warranty registration requirements;
• the documents required for the available rebates.

This list prevents comparing two prices that do not cover the same work. A lower quote may omit wall brackets, electrical work, a significant length of piping, connection protection, or complete commissioning.

In Saint-Polycarpe, the care taken with the installation beneath the deck illustrates this difference precisely. The performance of a GREE Free Match R32 depends on its technical specifications, but also on everything around it: clearances, anchoring, electrical work, piping, and how the two zones are configured.