Installation of a GREE FLEXX R32 ULTRA central heat pump in Massueville, Pierre-De Saurel RCM (Montérégie)

The disconnect switch, interlocking pavers, and vinyl siding: three details that no one photographs, yet that determine a central heat pump's service life

When a homeowner sends us a photo of an installation completed by another contractor and asks for our opinion, we almost never look at the unit first. We look at what surrounds it: the gray box mounted on the wall beside it, the ground beneath the unit, and the way the siding was penetrated. These three elements are what separate an installation that lasts twenty years from one that causes problems in its third year.

The Massueville project is a good example of how we address these three points on a GREE FLEXX R32 ULTRA central heat pump.

Massueville: a village center, not a suburban development

Massueville, in the MRC de Pierre-De Saurel, is a village of a few hundred residents south of Sorel-Tracy, organized around an historic core. The housing stock is made up mainly of older homes, often expanded over the decades, with siding replaced once or twice and foundations that are not always level.

Two local realities affect a central heat pump project in this area:

• No natural gas network. Heating is provided by electricity, oil, propane, or wood.
• Sensitivity to the appearance of façades. In several village centers in Montérégie, the installation of mechanical equipment visible from the street is governed by municipal regulations. We check the applicable zoning bylaw before choosing the location—not after drilling through the wall.

Here, the outdoor unit was installed on a side wall, out of view from the public road, on an area already finished with interlocking pavers.

The electrical side: what the gray box next to the unit really means

In the photo of this installation, a gray enclosure mounted on the wall to the right of the unit can be seen, connected by watertight flexible conduit. It is a disconnect—a local disconnecting device—and probably the component most often botched, or even completely omitted, on the residential installations we are called in to correct.

Why it must be there

The Code requires a disconnecting means within sight of the equipment and in the immediate vicinity. The rationale is not administrative: a technician opening the electrical compartment of an outdoor unit must be able to disconnect the power themselves, see that it is off, and know that no one will restore power while their hands are inside. A circuit breaker in the basement, behind a door, in a panel that someone could reset without realizing it, does not fulfill this function.

Three common mistakes in this regard:

1. The disconnect mounted on the unit’s service panel. It becomes impossible to remove the panel without dismantling the disconnect.
2. The disconnect installed behind the unit. Technically present, but practically inaccessible.
3. An enclosure not designed for outdoor use. Two winters later, the interior is corroded and the contacts overheat.

MCA 27.7 A and MOCP 30 A: what these two figures require

The outdoor unit GUD36W2/NhE-D(U) is powered at 208-230 V, with an MCA of 27.7 A and an MOCP of 30 A.

• The MCA (minimum circuit ampacity) dictates the minimum conductor rating. Below that, the cable overheats.
• The MOCP (maximum overcurrent protection) dictates the maximum circuit-breaker rating. Above that, the protection no longer protects much.

In other words: the circuit must be dedicated, sized for at least 27.7 A, and protected by a circuit breaker rated at no more than 30 A. Installing a 40 A breaker “to be safe” because the unit trips on startup is a dangerous response to a problem with another cause. The indoor section has its own requirements (MCA 5.3 A, MOCP 15 A) and its own circuit.

The connection itself

The watertight flexible conduit between the disconnect and the unit is not decorative: it absorbs the equipment’s micromovements and prevents vibration from being transmitted to the enclosure and connections. It must descend in a low loop before rising toward the unit’s entry point, so water running along the conduit drips off at the low point instead of entering the electrical compartment.

Panel capacity: check it before ordering

In an electrically heated village home with a water heater, stove, dryer, and sometimes a sump pump, adding two circuits—one of them 30 A—is not always possible on an existing panel. We perform the load calculation before ordering the equipment, never on the morning of the installation.

The interlocking pavers beneath the unit: January's trap

The unit is installed above a surface of interlocking pavers, which largely explains the choice to mount it on wall brackets rather than on a ground pad: no one wanted to cut into the landscaping.

This choice solves one problem and creates another, which must be addressed.

In heating mode, a heat pump produces water. The defrost cycle melts the frost that has accumulated on the outdoor coil, and this water drips down. On gravel, it soaks in. On interlocking pavers, in January, it freezes and gradually forms a sheet of ice. If this surface is a walkway—to the yard, the shed, or the recycling bin—the problem is no longer mechanical; it is human.

Our options, depending on the site:

• A strip of clean stone removed from the paving beneath the unit so the water can soak in instead of spreading.
• A drain pan with a discharge line directed away from traffic areas.
• A shift of a few dozen centimeters for the unit, where the layout allows, to move the dripping water out of the walkway.

We discuss this with the client when preparing the quote. A contractor who never addresses defrost water has probably never received a callback in February.

Installing against vinyl siding

The wall has vinyl siding, and that detail changes the method.

Vinyl is a flexible siding material, installed deliberately with room to float and absorb thermal expansion—a panel can move several millimeters between January and July. It provides no load-bearing capacity and cannot tolerate being compressed: a screw tightened fully into vinyl deforms it, cracks the panel in cold weather, and creates a path for water behind the siding.

The brackets were therefore anchored in the parged concrete foundation, beneath the vinyl siding, using hardware suitable for concrete. Anti-vibration pads are placed between the unit's feet and the support arms, and the bolts are tightened without crushing the pads—a pad compressed solid no longer does its job and transmits vibration into the wall, and therefore into the house.

Where the refrigerant line and wiring pass through the siding, the penetration is made with a sleeve and a slope toward the outside, then sealed with a product compatible with vinyl. Caulk applied directly to a moving vinyl joint peels off within a season.

The A2L R32 label on the side of the appliance

The mildly flammable refrigerant pictogram and the wording A2L R32 are visible on the unit's electrical box. This is not a warning to ignore, nor is it a reason for concern.

What this means in practice:

• Refrigerant repair and handling are reserved for personnel trained in A2L refrigerants, using compatible tools, vacuum pumps, and detectors. This is written on the label itself.
• The room's charge and ventilation matter for the indoor section, not the outdoor unit. A coil or fan coil installed in a cramped room is subject to different rules than the same appliance in an open basement.
• The A2L leak detection sensor is factory-installed on the FLEXX ULTRA range. It still needs to be connected and checked during commissioning, as documented on our checklist.
• Never drill into a component containing refrigerant, including to “run a wire through.”

A contractor who handles an R32 system exactly as they handled R410A five years ago has not updated their methods. This is a question to ask before signing, whether in Massueville, Montréal, Laval, Longueuil, or anywhere on the North Shore and South Shore.

The installed combination

Capacity, rebates, and maintenance: the decisions that follow installation

Why 34,000 BTU and not 48,000

The FLEXX ULTRA series goes up to 54,000 BTU. It would have been easy to propose a larger unit. We do not do so without good reason, and here is why.

An oversized unit reaches its setpoint too quickly, shuts off, restarts, and spends its life operating in the ranges where its efficiency is lowest. In summer, short cycles mean insufficient dehumidification: the house is cold and muggy rather than cool and dry. In winter, modulation loses its benefit because the unit operates constantly at the bottom of its range.

The selected combination modulates from 18,000 to 37,000 BTU/h. This range—not the nominal capacity—determines actual comfort. It was selected after a load calculation, not based on square footage, a method that almost systematically oversizes renovated homes.

LogisVert: the AHRI number is the key document in the application

Hydro-Québec's LogisVert program determines the rebate for an air-source heat pump based on its heating capacity at -8 °C, using a scale of approximately $120 per 1,000 BTU/h, with a maximum of around $6,700. It also provides enhanced amounts when the installation replaces oil or propane heating—a common situation in the Pierre-De Saurel RCM.

The requirements: be a residential property owner and an Hydro-Québec customer, have the work carried out by a contractor holding a RBQ licence, and install an approved, ENERGY STAR certified system bearing a valid AHRI number.

This last point deserves clarification. An AHRI number does not certify an individual unit: it certifies a specific combination of an outdoor unit and an indoor section. 217120760 corresponds exactly to the combination installed here. Changing the indoor section to an “equivalent” model from another product line, even from the same brand, invalidates the number and may result in a perfectly legitimate application being denied on technical grounds.

Since the rates are revised periodically, we confirm the amount applicable to the file before including it in a quote.

The maintenance, and the fact that the unit is now accessible

Mounting the unit on wall brackets above the paving has an advantage the customer had not anticipated: the unit remains accessible year-round, at working height, without having to clear a metre of snow before opening a panel.

The annual HVAC maintenance program we recommend for a central heat pump includes cleaning the outdoor coil, checking the charge and pressures, inspecting the electrical connections and tightening at the disconnect switch, inspecting the indoor-section condensate drain, checking the A2L sensor's operation, and replacing the filter. An outdoor coil clogged with pollen and maple seeds can lose several percentage points of efficiency in a single season—and in a village area surrounded by fields, buildup occurs faster than in the city.

Our coverage in Montérégie and Greater Montreal

At AirGreen, we install and maintain central heat pumps, ductless mini-split heat pumps, central air-conditioning systems, and heating equipment throughout Greater Montreal and the Montérégie region, including the Sorel-Tracy area, the RMC of Pierre-De Saurel, Saint-Hyacinthe, as well as Longueuil, Boucherville, Châteauguay, and Saint-Constant. We also serve Montreal, Laval, the North Shore, and the South Shore.

If you are considering a central heat pump and want a quote in which the electrical work, defrost-water drainage, and anchoring are costed and explained rather than left unmentioned, we come to your property, take measurements, and put every element in writing.