Installation of a GREE FreeMatch R32 2-head wall-mounted heat pump (GWHD(42)ND6MO) in Sorel-Tracy — replacement of an existing system

Replacing a wall-mounted unit is the only free opportunity to correct its installation position.

A replacement quote almost always comes with a silent assumption: same location, same holes, same plate. No one writes it down, no one discusses it, and yet it determines everything the customer will experience over the next twelve to fifteen years. It is the cheapest assumption to make and the most expensive to correct, because it turns 2011 installation errors into permanent 2026 constraints.

We have written several pages elsewhere about replacing an appliance: the window air conditioner replaced with a dual-zone system in Anjou, the through-wall unit in a Terrebonne condo, the overhaul of a multi-zone system left by another contractor in Delson, and the central system that failed in Léry. None of these pages covers the most common case in Quebec in 2026: a ductless wall-mounted heat pump replaced by another ductless wall-mounted heat pump. That is the case in this Sorel-Tracy project, and it is the only one where refrigerant piping already exists inside the wall.

The moment when moving something costs nothing

On a new HVAC installation, there is one rule we repeat from one job to the next: the position can be adjusted for free before the mounting plate is screwed in, and hardly at all afterward. During a replacement, this window opens only once, for a few hours, and closes at that same moment.

In practical terms, on the day of the replacement:

• Moving a head 20 or 40 cm on the same wall costs one penetration and finish repairs—that is, a fraction of the project price.
• Changing walls costs a length of piping, which is a real expense but remains nowhere near the cost of a second job two years later.
• Moving the outdoor unit two metres costs a length of refrigerant line and a base—and nothing else, since the unit has to be removed anyway.

Two years later, each of these adjustments becomes a complete job again, involving refrigerant recovery, removal, drilling, repairs, vacuuming, and recommissioning. We tell the customer this frankly when preparing the quote, because it is the only information that allows them to make a decision while changing their mind is still free.

The customer's fifteen years of complaints are the best design data available

With a new installation, we work with intentions: the customer tells us how they think they will use their rooms. With a replacement, we work with evidence. Fifteen years of actual use have produced a precise list of what never worked, and that list appears on no replacement quote form.

The questions we systematically ask before pricing a replacement:

1. Which room was never comfortable, and at exactly what time? A precise answer (“the office, between 2 p.m. and 5 p.m. in summer”) can be corrected. A vague answer cannot.
2. What disappointed you about the old system? This is the question that separates a correctable defect from an expectation that was never realistic. We formalized it for maintenance follow-up in Repentigny; it is even more useful here.
3. Was there an odor, a drip, or a recurring noise? Each of these three symptoms points to a different issue, and two of them can be fixed during reinstallation.
4. What has changed in the house since installation? A finished basement, a partition wall removed, windows replaced, or a home office set up in a room that used to be a guest room.
5. Did anything have to be moved to open the front panel or rinse the filter? If so, maintenance probably was not performed, and that explains some of the wear we are going to find.

A replacement quote that asks none of these five questions is not replacing a system: it is copying a 2011 invoice.

The replacement line item that quotes almost never include: the old pipe in the wall

This is the central technical issue in replacing any wall-mounted heat pump, and it is where two quotes can differ by several thousand dollars without the customer understanding why.

The old system operated on R410A. The new system operates on R32. Between the two, there is copper piping inside a wall, and one question that must be asked exactly once:

Can it be reused?

What needs to be checked before even considering it:

• The diameter. The FreeMatch requires 1/4 in. for liquid and 3/8 in. for gas per head. A line of a different diameter cannot be adapted; it must be replaced.
• The actual length and routing, measured rather than estimated, because they factor into the load calculation for the new unit.
• The condition of the copper and its insulation along the entire visible section: insulation that is crushed, open, or missing for even a few centimeters is enough to condemn that section.
• Charge history. A system that has been “topped up” without finding the leak is a system that has a leak. We never add refrigerant to a circuit whose history is not documented.
• Residual oil. This is the point that quick quotes ignore: compressor oil circulates with the refrigerant, and there is always some left in the tubing. Incompatible residual oil in the new circuit cannot be dealt with by “blowing through it with nitrogen.”

And one non-negotiable point: a flare is never reused. If we keep a section of line, it is cut square, deburred with the chips directed downward, and the flares are completely remade, with the nut installed before flaring and tightened with a torque wrench. We published the complete method—pressurized nitrogen before evacuation, a deep vacuum measured with a micron gauge rather than a needle, and a standing vacuum-rise test—on our Côte Saint-Luc page, and we are not repeating it here: it applies in full to a reused line, and even more rigorously.

The fundamental reason is that a hermetic compressor does not die of old age. It dies from contamination introduced on the day of installation—residual moisture and hygroscopic oil that form acids attacking the winding insulation over the years. During a replacement, the risk is not theoretical: the circuit being reconnected has already been in service for fifteen years.

Our position, stated before signing: we prefer to replace the line, and when the routing allows it, we replace it. When we keep it, it is after verification, and the work is quoted—not offered as a cost-saving measure.

The unit we remove is the site's only free measuring instrument

For an installation in Bois-des-Filion, we wrote that the filter from a wall-mounted unit reads like a diagnostic: uniform gray, one end dirtier than the other, an oily film, long fibers, fine black dust—each deposit tells the story of what the room has done. A unit removed after fifteen years is the same thing on a different scale. It is a recorder that has run for 130,000 hours at a site we did not design, for an owner who may not be able to describe what they observed.

We inspect it before sending it for recycling, and we record what we see in the file for the new system.

What the old outdoor unit teaches us

• Which face of the coil is fouled. A condenser draws air in through its rear and side faces and discharges it through the front fan: debris therefore enters the fin block from the outside toward the inside, and the visible face is the cleanest. A heavily loaded side face tells us where the dirty air came from, and therefore where not to place the new unit.
• Where the ice column formed. A wear or corrosion mark on the underside of the chassis, an ice imprint on the base, or a flat object left beneath the unit: defrost water returned to the same place every winter for fifteen years, and that place is visible.
• Whether the unit has lost its level. A base sagging on one side, an improvised shim under one foot, or a pan that retains water: the unit was no longer draining through its intended openings, which often explains the rest.
• Whether the fins have been flattened. A strip of fins bent down at shovel or string-trimmer height, or a fan guard dented by falling ice, pinpoints a site-related stress.
• Where the coating has pitted. In an exposed area—salted roadside, industrial atmosphere, sea spray—corrosion shows on the metal, not in the dirt. This is not the same failure as fouling, and it never produces an error code.

What the old indoor head tells us

• A yellowed or greasy enclosure on one side only indicates an aerosol source in the room and its direction.
• A runoff mark on the wall beneath one corner of the unit indicates a back-pitched drain. A ten-centimetre back pitch does not leak: it holds water, develops a biofilm, and returns six months later as an odour, without triggering any error code.
• A rusted mounting plate or screws that have been reused several times tells the story of an installation done twice.
• A warped or torn filter indicates that maintenance was done reluctantly, often because the unit was inaccessible.

None of this is a spectacular discovery. The point is elsewhere: these observations are free, and they will no longer be available after the truck leaves. We document them, and they help determine the new installation rather than decorate a report.

What happens to the old appliance

The decommissioned unit still contains refrigerant and oil until they have been recovered. The handling of halocarbons is regulated in Quebec and must be carried out by qualified contractors: recovery, removal, and transport to a recycling stream are a contract line item, not a service provided. This is also a good question to ask other bidders: what happens to the old unit, and who pays for it.

The installed system, and why this particular model

Thirty-three thousand BTU/h on a nominal 42,000 BTU compressor is an undersizing, and we do not present it otherwise. It was not selected based on the load; it was selected based on the route.

The layout was inherited: in an older street-facing house in Sorel-Tracy, the outdoor unit's location is constrained by the property, and the distance to the upstairs office is what it is. At 53 m of developed length:

• on the GWHD(36), whose factory charge covers 40 m, approximately this much would have had to be weighed 260 g of additional R32;
• on the GWHD(42), whose factory charge covers 50 m, an additional 60 g was required.

A unit operating close to its factory charge is a unit for which the minimum room-area verification required by the A2L classification of R32 must be repeated with little margin—and we repeat that verification using the final charge, not the factory charge. The GWHD(42) also accepts up to five heads, allowing the customer to add a basement zone without changing the compressor.

The honest price of this choice: a larger cabinet, 79 kg instead of 66, 63 dB(A) instead of 62, and a higher acquisition cost. On this project, the route took precedence over the catalog.

The electric baseboards were retained throughout, as on all our first-season projects.

Sorel-Tracy: 17,749 dwellings and a first generation of wall-mounted units reaching the end of its service life

Sorel-Tracy had 35,165 residents in the 2021 census, up 1.2% over five years, across 57.28 km², in 17,749 private dwellings, of which 17,069 were occupied. The city originated with Fort Richelieu, established in 1642, at the confluence of the Richelieu River and the Saint Lawrence River, along the western shore of Lake Saint-Pierre; it was called William-Henry from 1787 to 1845, and the voluntary merger of Sorel and Tracy was completed in March 2000.

It is also an industrial city—shipyards, Marine Industries, and the iron and titanium complex now operated by Rio Tinto—so it is a city of working-class homeowners who adopted wall-mounted heat pumps early and in large numbers. This housing stock of nearly eighteen thousand units now contains a significant number of first-generation wall-mounted units installed between 2008 and 2014. The South Shore's replacement wave runs through Sorel-Tracy, and it is ahead of that in newer suburbs.

In the Pierre-De Saurel RCM, we recently also documented a corner installation in Saint-David and an installation along the Richelieu in Saint-Ours: three projects, three different problems, within a twenty-five-kilometre radius.

Rebates

The installed unit is ENERGY STAR certified and AHRI certified, which is an entry requirement for most Quebec programs, including Hydro-Québec's LogisVert and Rénoclimat. However, be careful with a replacement: several programs treat adding a heat pump and replacing an existing heat pump differently. We verify eligibility for the project before promising it, never based on a brochure.

Contact us

At AirGreen, we offer sales, HVAC installation, and HVAC maintenance in Montreal, Laval, Longueuil, the North Shore, and the South Shore, including the Pierre-De Saurel RCM: Sorel-Tracy, Saint-Ours, Saint-David, Yamaska, Massueville, Saint-Robert, Sainte-Victoire-de-Sorel, Saint-Aimé, and Saint-Gérard-Majella. Our teams hold the required RBQ licences, and every heat pump replacement ends with documented commissioning, a file provided to the customer, and warranty registration.

To have an existing system assessed before it fails: sales@airgreen.ca.