Installation of a GREE Free Match R32 three-head heat pump in Saint-Dominique

In Saint-Dominique, a multizone installation designed for a technical passage already occupied by several HVAC units

This installation, completed in Saint-Dominique, in Montérégie, presents a very different constraint from a heat pump installed in a large, open yard. Here, the outdoor unit of a GREE Free Match R32 three-head heat pump had to be installed in a narrow passage along a brick wall where several mechanical units were already present.

The site photograph immediately makes the context clear. Our GREE unit appears in the foreground, installed high up on a sturdy metal structure secured to the masonry. Behind it, other outdoor units already occupy the same façade. A door is located directly beneath the installation area, a metal staircase partially closes off the end of the passage, and a metal terrace or walkway ceiling reduces the space available above the units.

In this type of environment, the work is not limited to finding enough space for the condenser. It is necessary to consider air circulation, vibrations, access for maintenance, equipment weight, refrigerant lines, electrical wiring, and the three branches supplying the indoor units.

This is precisely the kind of project where planning for multizone HVAC installation makes a significant difference.

Using vertical space rather than blocking the passage at ground level

The corridor visible in the photo clearly serves as a passageway and provides access to the building’s systems. Placing the GREE unit on the ground would have reduced this space and made movement, cleaning, and future service much less convenient.

We therefore used the upper part of the wall.

The outdoor unit rests on two metal brackets reinforced with diagonal braces. This geometry transfers the load to the wall while keeping the ground completely clear beneath the unit.

This decision provides several advantages:

• the passage remains usable;
• the door beneath the installation remains accessible;
• the unit is less exposed to debris on the ground;
• the underside of the unit remains visible for inspection;
• water from defrosting can be managed without burying the unit in a buildup on the ground;
• the technician has direct access to the side connections;
• the unit fits into the layout of the other equipment already installed high up along this passage.

The weight of a three-head Free Match system requires a proper structure

A multizone heat pump must never be mounted on a support chosen solely according to its apparent dimensions.

According to the table on page 2 of the supplied documentation, the outdoor units capable of powering three indoor units start with the 24,000 BTU/h model, weighing 112.5 lb. The 30,000, 36,000, and 42,000 BTU/h models reach, respectively, 145.5 lb, 173.1 lb, and 174.2 lb.

This mass must be supported for years despite:

• compressor vibrations;
• thermal cycles;
• winter conditions;
• humidity;
• defrosting operations;
• maintenance work.

In masonry like that visible in Saint-Dominique, we must consider the type of anchoring, the quality of the existing support, and the position of the fastening points. The visible brackets are also fitted with supports between the rails and the outdoor unit to limit direct mechanical transmission.

Installing several condensers on the same façade without creating a recirculation zone

The presence of other outdoor units behind the GREE makes this installation particularly interesting.

Each heat pump must draw outdoor air through its heat exchanger and then discharge a significant volume of air through its fan. When several units are installed in a relatively narrow passage, care must be taken to prevent one machine from directly drawing in the air discharged by another.

This could cause thermal recirculation, particularly unfavorable during periods of high demand.

We must therefore consider:

• the orientation of each fan;
• the distance between the units;
• the corridor width;
• obstacles in front of the units;
• the ceiling above;
• walls that could reflect or trap the discharged air.

In the photograph, the GREE’s large ventilated façade faces the open space of the passage. The connection side remains near the brick wall, allowing the lines to be grouped without obstructing the unit’s main face.

This arrangement is far more important than it may seem. A unit with excellent technical specifications can lose some of its efficiency if its outdoor air exchange is compromised by poor placement.

Why a three-head heat pump suited this configuration

The GREE Free Match R32 is a multi-zone system: a single outdoor unit can power several indoor units.

For a building where three spaces need to be treated separately, this configuration avoids adding three new condensers to an already occupied façade.

This is particularly relevant in a passage like the one photographed in Saint-Dominique. The outdoor mechanical space is limited. Adding a unit for each room would have considerably increased the footprint and multiplied the electrical supplies and service access points.

With a three-head configuration, we can instead serve three zones with a single outdoor compressor.

The GREE technical sheet indicates that:

• the 24,000 BTU/h unit can connect two to three indoor units;
• the 30,000 BTU/h unit can connect two to four;
• the 36,000 BTU/h unit can connect two to four;
• the 42,000 BTU/h unit can connect two to five indoor units.

The plate that would allow the exact capacity of the photographed unit to be identified with certainty is not sufficiently legible in the supplied image. We therefore do not assign it a BTU rating without confirmation.

Three zones allow much more precise control indoors

A single wall-mounted unit can be highly effective in an open-plan area. It becomes less effective when attempting to cool several rooms separated by walls and doors.

A three-head heat pump allows the air treatment to be placed directly in the zones that need it.

Depending on the building layout, this may mean:

1. an indoor unit for a main area;
2. a second for a separate room;
3. a third for another level or a more distant zone.

Each indoor unit has its own fan and its own setpoint.

The outdoor inverter compressor then adjusts its output to the combined demand of the zones.

Three independent controls do not mean three opposing modes

It is possible to use different setpoints in the three spaces. For example, one zone can be maintained at 21 °C and another at 23 °C.

However, the three units share the same refrigeration system. In a conventional multizone system, they must operate in compatible modes. One head must not be set to heating while another simultaneously requests cooling.

This explanation is part of the commissioning we carry out after theheat pump installation.

The technical side of the photo: three neatly grouped circuits

A particularly revealing detail appears to the right of the GREE unit.

Several sets of insulated pipes leave the connections and are grouped against the wall. In a three-head installation, each indoor unit has its own refrigerant line running to the outdoor unit.

This therefore requires managing many more pipes than with a single-zone wall-mounted air conditioner.

We aim to avoid:

• pipes that hang freely;
• bends that are too tight;
• crushed insulation;
• the contacts that could cause vibrations;
• the routes that prevent the service panel from opening;
• the cables left unsupported.

On this project, the connections are grouped on the same section of the wall and run up into the technical area rather than crossing the corridor.

The total length of the three branches must be calculated

Page 2 of the GREE documentation specifies that the outdoor units shown use liquid pipes of 1/4 po and gas pipes of 3/8 po.

For a configuration accommodating three heads, the maximum total length varies depending on the outdoor unit:

• 60 m for the 24,000 BTU/h model;
• 80 m for the 30,000 BTU/h;
• 80 m for the 36,000 BTU/h;
• up to 100 m for the 42,000 BTU/h.

The allowable height difference reaches 15 m on the 24,000 BTU/h unit and 25 m on the higher-capacity outdoor units concerned.

It is important to discuss the total length. If three heads are installed in different areas of the building, all three runs must be considered in the design.

A head located directly behind the exterior wall may require relatively little piping, while another located several rooms away or on another level may require a significantly longer run.

R32 and the cooling charge: no room for guesswork

The Free Match series presented in the document uses R32 refrigerant. The manufacturer also indicates a precharged amount of refrigerant corresponding to a certain pipe length, as well as an additional charge of 20 g/m when the installed lengths require it.
On a three-head installation, it therefore becomes particularly important to measure the runs.

Our work sequence notably includes:

1. preparing the pipes;
2. making the connections;
3. checking for leaks;
4. evacuating the system;
5. calculating the lengths;
6. adjusting the charge when required;
7. commissioning of each indoor unit.

The GREE datasheet also mentions an A2L leak detection sensor included, as well as self-diagnostics, intelligent defrosting, and G10 inverter technology.

What this Saint-Dominique installation teaches us about the performance, maintenance, and selection of a multi-zone system

Up to 21 SEER2 and 10 HSPF2

The documentation for the GREE Free Match R32 advertises efficiency of up to 21 SEER2, 12.5 EER2 and 10 HSPF2. It also indicates a cooling range of -30 °C to 48 °C and a heating range of -30 °C to 24 °C.

These data are useful for comparing different systems, but the actual performance of an installation also depends on factors that are not found in a brochure:

• sizing quality;
• indoor unit placement;
• air circulation around the outdoor unit;
• pipe length;
• cooling load;
• filter cleanliness;
• setpoint temperatures;
• building insulation.

The Saint-Dominique project particularly well illustrates the building insulation factor. outdoor air circulation. With several condensers aligned along the same façade, the location of each must be studied to preserve adequate heat exchange.

Operation down to -30 °C must be interpreted correctly

The manufacturer indicates a heating range down to -30 °C.

For an installation in Quebec, this information is important, but it should not be confused with a guarantee of full rated capacity at -30 °C.

As the outdoor temperature decreases, two things happen simultaneously: the building loses more heat, and the available performance of a heat pump varies according to the conditions.

To determine whether a system is genuinely suitable as a primary heating source, it is therefore necessary to examine the building’s heat losses and the performance of the exact combination at cold temperatures.

Defrosting deserves even more attention when the unit is installed at height

During heating, frost may form on the outdoor coil. The Free Match has an intelligent defrosting, according to the manufacturer’s specifications.

When the frost melts, water flows beneath the unit.

The unit photographed in Saint-Dominique is located high above a passageway. This location keeps the appliance away from accumulations directly on the ground, but it also requires checking where the water will fall and freeze.

In a passageway used daily, the area beneath a heat pump must not be allowed to become slippery.

The owner or manager must therefore:

• monitor ice accumulation;
• keep the drainage area clear;
• avoid storing equipment directly beneath the unit;
• maintain clearances around the fan;
• have any abnormal ice formation checked.

The electrical box must remain accessible

To the right of the outdoor unit, an electrical box mounted on the masonry can also be seen.

Access to the electrical components and disconnecting device is part of the site planning. We avoid enclosing these elements behind the lines or in an area that cannot be reached without dismantling part of the installation.

All outdoor units in the range presented in the documentation operate on 208/230 V.

For models capable of accommodating three indoor units, the indicated minimum circuit ampacity varies from 19.5 A to 30 A, while the maximum overcurrent protection ranges from 25 A to 45 A depending on the group.

It is therefore not possible to choose the circuit breaker solely because the installation has three heads. We must refer to the exact model and its nameplate.

The sound level must be considered differently in a corridor

The technical table indicates, at high level, an outdoor sound pressure of 58 dB(A) for the 24,000 BTU/h unit, 62 dB(A) for the 30,000 BTU/h unit, and 63 dB(A) for the 36,000 and 42,000 BTU/h models.

In reality, acoustic perception depends greatly on the environment.

A passageway surrounded by masonry and partially enclosed by a metal structure may reflect more sound than a completely open courtyard. Vibrations can also travel through the supports if they are not properly isolated.

We must therefore consider the following together:

• the unit’s noise level;
• the sturdiness of the brackets;
• the anti-vibration mounts;
• the lines that could touch the wall;
• the proximity of windows or occupied rooms.

Maintenance: never turn this corridor into a storage area

The photo shows why future accessibility is a central element of this project.

Several outdoor units are installed in the same passageway. Over time, it would be easy to start storing tools, boxes, bins, or materials in front of the equipment.

This is precisely what must be avoided.

To preserve operation and facilitateHVAC maintenance, we recommend keeping:

• the fan face unobstructed;
• the service panels accessible;
• the area around the connections clear;
• the lines visible for inspection;
• the underside of the support accessible;
• the electrical device within reach.

A technician must be able to service a heat pump without having to move a large amount of material or dismantle neighboring installations.

Three indoor units also mean three indoor maintenance points.

The outdoor unit is only one part of the system.

Each indoor unit has its own filter, heat exchanger, blower, and condensate drain.

Maintenance must therefore be performed in each of the three zones.

We recommend monitoring:

• the cleanliness of the filters;
• the strength of the airflow;
• the appearance of odors;
• any trace of water;
• an unusual noise coming from the blower;
• an abnormal difference in performance between two indoor units.

If two units are operating properly while a third appears to be losing efficiency, this comparison is very helpful for diagnosis.

ENERGY STAR, AHRI, and rebates: the combination is what matters

The table on page 2 provides references separate AHRI listings for ductless, ducted, and mixed configurations, as well as ENERGY STAR identification for the equipment shown.

The documentation also indicates eligibility for local rebates.

However, a heat pump should never be sold with a promise of a subsidy amount based solely on the name “GREE Free Match R32.”

The following must be verified:

• the exact outdoor model;
• the three indoor units;
• the AHRI combination;
• the applicable program;
• the installation date;
• the building’s characteristics;
• required documents.

We recommend keeping the invoice, model numbers, serial numbers, photographs of the nameplates, and documents related to registration.

A warranty to register after the work is completed

The documentation provided indicates a standard ten-year warranty, with two additional years potentially available through Wolseley when the product is registered and/or proof of installation is provided, subject to the applicable conditions.

A three-head configuration includes several serial numbers. The information for the outdoor unit and the three indoor units should therefore be kept as soon as the work is completed.

The mistakes we particularly seek to avoid in this type of installation

Installing the outdoor unit on the ground in an already narrow passage

This reduces airflow and exposes the unit more to debris, snow, and impacts.

Undersizing the brackets

A three-head multi-zone system can weigh more than 170 lb, depending on its capacity. The support must be designed accordingly.

Positioning several units without considering their air discharge

Poor orientation can encourage recirculation and reduce efficiency.

Blocking access to the electrical box

A clean installation must also remain easy to diagnose and de-energize.

Leaving the different refrigerant branches unorganized

Three heads involve several lines, cables, and connections. Their layout must allow for inspection and maintenance.

Choosing BTUs simply according to the number of rooms

The actual thermal load of each zone remains the main criterion.

An installation that makes intelligent use of every available square foot

The Saint-Dominique clearly shows that a multi-zone heat pump is not always installed in a completely open yard. Sometimes, the new equipment must be integrated into an already crowded mechanical environment.

Here, we used the brick wall and the available height to preserve the ground-level corridor. The GREE Free Match R32 three-head now shares the façade with other equipment while retaining its own ventilation zone, access to connections, and a structure adapted to its weight.

This is a type of work where several details become inseparable: location, anchoring, vibrations, airflow, circuit length, electricity, and future maintenance.

At AirGreen, we apply this same approach to our heat pumps, of wall-mounted air conditioners and multi-zone systems in Saint-Dominique and elsewhere in Montérégie, as well as Montréal, Laval, Longueuil, on the North Shore and on the South ShoreWe adapt the installation to the reality of the building so that the result is not only functional on the day it starts up, but also accessible and consistent several years later.