Three zones connected to a single system: an installation where the positioning of each head matters just as much as the outdoor capacity
At Saint-Marcel-de-Richelieu, we carried out a HVAC installation of a 3-head GREE FreeMatch R32 heat pump, a multi-zone configuration designed to condition several indoor spaces with a single outdoor unit. The photograph taken during commissioning shows one of the wall-mounted units installed very high on the wall, immediately below the ceiling. The airflow louver is open, and the front display indicates 16 °C, indicating that the unit was powered and in use during the checks carried out around the installation.
This visible detail may seem simple, but it sums up an important part of the work. An indoor unit cannot be placed solely where it appears least conspicuous. We must simultaneously consider air intake, airflow direction, refrigerant line routing, condensate drainage, future maintenance, and wall structure.
With a three-head heat pump, this operation is repeated in three different zones. The needs are not necessarily identical from one room to another, and the three lines must then converge at the same outdoor unit without exceeding the technical limits of the GREE FreeMatch R32 system.
What the indoor unit installed in Saint-Marcel-de-Richelieu shows
The wall-mounted unit visible in the photo is installed near the ceiling, with its front parallel to the wall and its lower louver fully accessible. The white casing blends into the room's light-colored finish, reducing its visual impact.
The location is advantageous for several reasons.
The head is positioned high enough to allow treated air to be projected into the room rather than directly at occupant level. In cooling mode, cooler air naturally descends after being distributed. In heating mode, louver orientation becomes particularly important to direct warm air toward the occupied area rather than letting it accumulate near the ceiling.
We therefore check not only the physical position of the unit, but also:
- the space available for air intake;
- the opening of the front panel;
- access to the filters;
- the full range of motion of the louver;
- the direction of the airflow;
- the absence of any immediate obstruction;
- the possibility of carrying out a HVAC maintenance without dismantling finishing elements.
The photograph also shows that the network is not exposed in front of or beneath the head. The lines leave the unit through a designated side or rear area. This finish is important in a residential room, where the owner wants to enjoy the comfort of a wall-mounted heat pump without giving the impression that a mechanical network runs through the wall.
Why we never choose a head’s location based solely on aesthetics
A head can be perfectly centered on a wall and still function poorly in the room.
We first analyze the movement of the air. A unit placed directly above a large piece of furniture, behind a thick curtain, or facing an obstacle may have difficulty distributing its airflow properly.
We also avoid blowing air directly:
- on a bed;
- on a sofa used for several hours;
- on a desk;
- in an area where occupants remain stationary;
- against a wall that is too close.
In this installation, Saint-Marcel-de-Richelieu, the head is mounted high and the air outlet remains completely unobstructed. This configuration allows the louvers to adjust the direction of the air without immediately encountering an obstacle.
Clearance near the ceiling requires precision
The higher a unit is installed, the more precisely the work must be done.
The top of the head is generally used for air intake. If there is insufficient space, airflow may be disrupted. Enough room must also be kept to remove or lift the filters, depending on the unit’s design.
A few centimeters can also determine whether the copper lines can be bent properly behind the head.
We never force the copper piping to fit a unit into a space that is too restricted. A crushed or overly tight bend can restrict refrigerant flow and create a mechanical weakness that may not become apparent on the day of installation.
A three-head heat pump is not simply three air conditioners connected together
The principle of a GREE FreeMatch R32 is multi-zone: several indoor units share the same outdoor unit.
GREE documentation also specifies that different FreeMatch outdoor units accept different numbers of heads. The GWHD(24)ND6MO model can accommodate two to three indoor units, the GWHD(30)ND6MO and GWHD(36)ND6MO models can accommodate two to four, while the GWHD(42)ND6MO can accommodate up to five. All outdoor units listed in the table operate at 208/230 V.
This means that a three-head installation can be built around outdoor units with several different capacities.
The number “three” therefore does not automatically tell us the system’s capacity.
The specifications list, among other things, nominal cooling capacities of 24,000 BTU/h, 28,400 BTU/h, 36,000 BTU/h and 42,000 BTU/h for outdoor units capable of accepting three indoor units. The corresponding nominal heating capacities are 24,000, 30,000, 36,000, and 44,300 BTU/h.
The exact model number of the outdoor unit for this installation is not visible in the supplied photograph. We therefore do not artificially assign it a specific capacity. To determine an installation’s exact BTU rating, we always use the model numbers of the outdoor unit and the three indoor units.
Sizing must be carried out room by room
The three indoor units do not necessarily need to have the same capacity.
A relatively small bedroom may have a limited heat load, while an open-concept area with extensive glazing may require much more.
Before installation, several parameters influence our selection:
- zone area;
- window orientation;
- amount of glazing;
- solar exposure;
- insulation level;
- number of exterior walls;
- room floor;
- ceiling height;
- air infiltration;
- room occupancy;
- heat-generating appliances.
An indoor unit that is too small may run continuously under the most demanding conditions. An oversized unit, on the other hand, may reach its setpoint very quickly and reduce its ability to maintain consistent dehumidification in summer.
The right choice is therefore not “the largest possible unit,” but a coherent combination of the three zones and the outdoor unit.
Shared outdoor capacity among the three units
There is a fundamental difference between three single-zone systems and a multi-zone heat pump.
With three independent systems, each indoor unit has its own outdoor compressor. With the GREE FreeMatch R32, all three zones use the same outdoor unit.
When only one indoor unit calls for substantial heating or cooling, the system can direct a significant portion of its capacity to that zone. When all three units operate simultaneously, the available capacity is distributed according to demand.
This is precisely why the outdoor unit must be selected as part of a complete system.
Performance suited to Quebec's wide temperature variations
According to the GREE technical specifications, the FreeMatch R32 range can achieve 21 SEER2, 12.5 EER2 and 10 HSPF2. The indicated cooling operating range extends from −30 °C to 48 °C.
The published heating range, meanwhile, extends from −30 °C to 24 °C.
For an installation at Saint-Marcel-de-Richelieuthese features are particularly relevant. The Montérégie climate involves significant seasonal variations: summer heat and humidity, highly variable shoulder seasons, and pronounced winter cold.
A heat pump capable of operating at low temperatures therefore makes it possible to use the same system to meet a significant portion of the heating needs and to cool the spaces.
However, it is important to distinguish minimum operating temperature of the capacity actually available at that temperature. A heat pump can continue to operate at −30 °C without necessarily providing exactly the same amount of heat as it would at a milder outdoor temperature.
A system with G10 Inverter technology
GREE also identifies the advanced technology in its documentation G10 Inverter, as well as intelligent defrosting, self-diagnostics, automatic voltage adaptation, and quiet operation.
Inverter modulation is particularly well suited to a three-unit configuration.
The building’s demand varies continuously. At one point, all three zones may be active. A few minutes later, two rooms have reached their target temperature and only the third still requires substantial capacity.
The compressor can then adjust its operation instead of working solely according to an on-off, full-power logic.
For the owner, this modulation generally results in a more consistent temperature and operation better suited to changing loads.
The three indoor units can have different setpoints, but not opposite demands
An important feature of multi-zone systems should be explained when the installation is handed over.
Each indoor unit has its own controls and can have its own setpoint. For example, one zone can be set to 21 °C and another to 23 °C.
However, units connected to the same outdoor unit generally operate in the same primary mode.
It is therefore not normally possible to request heating in one zone and cooling in another at the same time.
This situation occurs mainly in spring and fall, when a very sunny room becomes warm while another remains cool. Proper management of setpoints and ventilation can generally reduce these conflicts.
What the 16 °C display tells us in the photo
The digital display visible on the indoor unit installed in Saint-Marcel-de-Richelieu indicates 16 °C, while the air discharge louver is open.
This image was therefore taken while the unit was powered on and operating or in test mode. A very low setpoint such as 16 °C is commonly useful during certain air-conditioning performance checks because it keeps demand active long enough to monitor the system’s behavior.
For everyday use, we do not necessarily recommend setting the temperature that low.
Lowering the setpoint from 22 °C to 16 °C does not necessarily make “cold air come out six times faster.” It simply requires the system to continue cooling until it reaches a much lower temperature.
For most occupants, a reasonable and stable setpoint offers a better balance between comfort, humidity, and energy consumption.
R32: a refrigerant that requires adapted procedures
As its name suggests, FreeMatch R32 uses R32 refrigerant.
GREE documentation also specifies that the platform integrates an A2L leak detection sensor.
This function adds a level of monitoring, but it never replaces a properly executed refrigeration installation.
During commissioning, we carry out, among other things:
- properly preparing the copper tubes;
- making and inspecting the flared connections;
- tightening the connections;
- the leak test;
- fully evacuating the circuit;
- checking that the vacuum holds;
- opening the valves;
- calculating the additional charge when necessary;
- a new check of the connections.
Vacuum evacuation is a particularly important step. It is not used only to “remove air”; it also eliminates moisture from the system before the refrigerant circulates through it.
Line lengths must be added together in a three-head system
A multi-zone installation can quickly accumulate much more piping than a single installation.
GREE documentation indicates maximum total lengths of up to 100 meters depending on the outdoor unit. For models that can supply three units, the limits include 60 m for the GWHD(24), 80 m for the GWHD(30) and GWHD(36), and 100 m for the GWHD(42).
We must therefore measure:
- the route of the first head;
- that of the second;
- that of the third;
- their total length;
- the height differences.
A single branch may be relatively short while the system as a whole exceeds a significant limit.
An additional charge that cannot be estimated by eye
The technical page also specifies the precharged lengths for the different units and an additional charge indicated at 20 g/m when the system conditions require it.
On a three-head heat pump, this information must be calculated carefully.
We do not add refrigerant randomly based solely on an instantaneous pressure reading. The lengths are measured, and the required quantity is determined according to the manufacturer’s specifications.
An incorrect charge can affect:
- capacity;
- efficiency;
- operating temperatures;
- compressor stability;
- the system’s service life.
The published line diameters for the range
For the outdoor units listed in the documentation, GREE specifies a liquid line of 1/4 po and a gas line of 3/8 po.
This information must always be checked against the actual combination of indoor units.
We never automatically reuse existing lines simply because they are already present in a wall. Their diameter, condition, insulation, cleanliness, and compatibility with the new system must be verified.
Three condensate drains must function properly
Each head produces water when it cools and dehumidifies.
With three indoor units, there are therefore three drains to check.
Since the visible indoor unit in Saint-Marcel-de-Richelieu is installed very high on the wall, gravity drainage can be particularly beneficial when the building layout permits it. Nevertheless, a continuous slope must be maintained to the outlet.
We avoid:
- reverse slopes;
- compressed sections;
- poorly secured pipes;
- connections that may leak;
- drain lines that may back up.
An installation may cool the room perfectly during commissioning while still developing a water leak several hours later if the drainage has not been tested.
We therefore check each circuit separately.
The electrical supply depends on the outdoor unit actually selected
All the FreeMatch R32 outdoor units shown in the table operate on 208/230 V, but the electrical requirements vary significantly depending on capacity.
Among the models that can power three indoor units, the specifications indicate:
- GWHD(24): MCA 19.5 A and MOCP 25 A;
- GWHD(30): MCA 23 A and MOCP 35 A;
- GWHD(36): MCA 30 A and MOCP 45 A;
- GWHD(42): MCA 30 A and MOCP 45 A.
We systematically check the nameplate before installing the circuit.
Simply saying, “It’s a three-zone system, so it needs this particular circuit breaker,” would be incorrect. Two three-zone installations may have significantly different electrical requirements.
A commissioning in which each zone is identified
When there is only one indoor unit, the connection between the outdoor unit and the indoor unit leaves no room for ambiguity.
With three indoor units, each pair of lines must correspond to the correct wiring.
We therefore identify the circuits to prevent a control from zone A from being associated with zone B on the refrigeration side.
Before completing the project, we check:
- each indoor unit individually;
- simultaneous operation of multiple indoor units;
- remote controls;
- louvers;
- fans;
- supply-air temperatures;
- drains;
- communications;
- abnormal noises;
- the outdoor unit’s operation.
This step is essential for a multi-zone HVAC installation reliable.
The mistakes we seek to avoid on this type of project
Installing the indoor unit too close to the ceiling
An appliance installed too high may lack enough space to draw in air or become difficult to service.
Choosing capacity based solely on floor area
Floor area is only one of several factors. Orientation, windows, and insulation can significantly change the load.
Sizing the outdoor unit by simply adding the three indoor units together
A multi-zone configuration must comply with GREE limits and the building’s actual needs.
Neglecting condensate drainage
A slight slope defect can cause water damage even when the refrigeration system is working perfectly.
Cross-connect the circuits
The lines and wiring for each head must remain correctly paired.
Close the openings before testing
We keep access to the critical sections until the system's airtightness, drainage, and operation have been validated.
Certification, warranty, and potential rebates
Page 2 of the GREE documentation lists numbers AHRI distinct ones for ductless, ducted, or mixed configurations, and also indicates the presence of ENERGY STAR references for the product line.
For a rebate application or to document an installation's performance, the AHRI reference must match the combination actually installed.
It is not enough to know the GREE brand or the FreeMatch name.
The datasheet also mentions a 10-year standard warranty, as well as an additional two-year extension with Wolseley when the registration and/or proof-of-installation conditions are met. It also specifies that local rebates may be available.
Actual eligibility depends on the combination selected and the program rules in effect when the application is submitted. We therefore recommend keeping the model numbers, serial numbers, invoices, and AHRI references associated with the system.
An installation that appears simple once completed, but relies on many details
In the photograph taken in Saint-Marcel-de-Richelieu, the indoor result is intentionally discreet: a white head installed high up, an accessible airflow louver, no long visible line on the wall, and a unit operating during the checks.
What the photo does not show is just as important.
Behind this head are a refrigerant line set, a communication cable, drainage, and a connection to an outdoor unit that also serves two other zones.
At AirGreen, we approach these projects as complete systems rather than as a succession of three independent installations.
We carry out our installations of multi-zone heat pumps, and wall-mounted air conditioners and our work on HVAC in Greater Montreal, particularly in Montreal, Laval, and Longueuil, on North Shore and on the South Shore, as well as in several areas of Montérégie.
In Saint-Marcel-de-Richelieu, the value of this GREE FreeMatch R32 installation lies precisely in this balance: three indoor zones with their own controls, a single outdoor unit, and a wall-mounted layout designed to preserve comfort, airflow, and ease of maintenance.
A high-performance three-head heat pump therefore does not begin with starting the compressor. It begins with choosing each location, calculating the requirements, planning the lines, and commissioning the system so that none of the three zones is left to chance.