Water determines an outdoor unit's lifespan, and in Sorel-Tracy, it comes from every direction.
The final construction photo was taken in the rain, in the backyard of a Sorel-Tracy, MRC de Pierre-De Saurel home. It shows a 3-ton GREE FLEXX ULTRA R32 central heat pump suspended from two galvanized supports anchored in the concrete foundation, beneath vinyl siding. On the left, a gutter downspout with an extension discharges onto the paved walkway. On the right, a vegetable garden with cucumber plants growing on trellises. In the background, the shared property-line fence and the neighboring house, a few meters away.
Four seemingly ordinary elements. Together, they determine whether this unit will enjoy a long, healthy fifteen-year life or a difficult eight-year one.
Three water sources, three distinct treatments
The gutter downspout
A downspout that discharges in the immediate vicinity of an outdoor unit creates a three-stage situation. In summer, the water splashes the bottom of the coil and deposits roof sediment there—dust, shingle particles, and organic debris. In autumn, this sediment retains moisture against the aluminum fins. In winter, the water that accumulates in the same spot freezes into a sheet of ice, and the heat pump's defrost cycle only adds to it.
We have two requirements on this point, documented in the file: the downspout extension must carry the water beyond the unit's footprint, and it must not be moved in the spring “to mow” and then forgotten. It is the simplest instruction on the entire project, and the one most often neglected.
Defrost water
In heating mode, a central heat pump discharges the water produced during each defrost cycle through the bottom of its chassis. Over the course of a season, the volume is considerable.
This is one of the reasons why the unit is suspended above the paved walkway rather than placed on the ground in the garden bed. The water falls onto a stable, well-draining surface, away from the loose soil of the vegetable garden. A unit placed directly on garden soil sinks on one side after two or three winters, loses its level, and stops draining properly.
Air humidity: the real particularity of Sorel-Tracy
This is the most important technical point of this installation, and the one discussed the least.
Frost does not form on an outdoor coil simply because it is cold. It forms when the coil surface is both below 0 °C and below the dew point of the air. The frosting rate is therefore highest not in extreme cold, but in the range of approximately 0 °C to -7 °C with very humid air. Below -15 or -20 °C, the air contains so little water vapor that frosting slows significantly.
Sorel-Tracy is located at the confluence of the Richelieu and St. Lawrence Rivers, at the entrance to Lake Saint-Pierre and its marshes. The fog in November and March is very real there. In practical terms, a heat pump installed here spends more hours in the maximum-frosting window than an identical unit installed thirty kilometers inland.
What we do with it:
- We check the complete defrost cycle during commissioning, stopwatch in hand, rather than relying on startup.
- We leave more generous clearance beneath the unit so that defrost water drains away instead of refreezing against the chassis.
- We explain to the customer that a little visible vapor coming from the unit in November is a sign of normal defrosting, not a malfunction. It is the first service call we receive every fall, and it can be avoided with two sentences at delivery.
The wall exhaust outlet: the source of frost no one suspects
A white plastic exhaust grille is located on the wall immediately to the right of the unit. Whether it serves a dryer, range hood, or bathroom fan, it discharges warm, moisture-saturated air.
When discharged onto an outdoor coil operating in heating mode, this air produces exactly what we are trying to avoid: a local influx of moisture that condenses and instantly freezes on the fins. The unit then enters defrost mode more often than necessary, and each defrost cycle is a pause in the home's heating.
We positioned the unit outside this grille's discharge cone. When clearance is insufficient—which often happens in the narrow yards of Sorel-Tracy or Longueuil—the solution is to redirect the wall discharge, not move the unit two inches and hope that will be enough.
The vegetable garden, a more demanding neighbor than it appears
The cucumber plants growing on a trellis to the right of the unit are charming in July. They are also climbing plants placed less than two feet from a coil.
Three instructions given to the customer:
- Nothing should climb onto the appliance. A vine growing into the fins blocks airflow and traps moisture against the aluminum.
- Mulch and compost must remain outside the footprint. Organic matter splashed by rain sticks to the bottom of the coil.
- Cleaning is done with plain water, at low pressure, from top to bottom. A high-pressure jet permanently bends the aluminum fins, and a bent fin never straightens completely.
Anchoring an outdoor unit to a house with vinyl siding: what happens beneath the siding
Never anchor into vinyl
This is obvious to an installer and a surprise to most homeowners. Vinyl siding has no structural capacity: it is hung, it floats, and it expands and contracts by several millimeters between January and July. A screw driven into the vinyl to hold 187 lb will not hold, and it will deform the panel in the process.
On this house, the two galvanized braces are anchored directly into the exposed concrete foundation, below the siding line. The load is transferred into a structural element, and the siding has nothing to support.
What a concrete anchor requires
- The right type of anchor for concrete, installed to the embedment depth specified by its manufacturer—not an improvised masonry anchor.
- Maintaining edge distances. An anchor placed too close to the upper edge of a foundation can cause the concrete to spall, immediately or after a few freeze-thaw cycles.
- A clean, dust-free hole. Residual drilling dust significantly reduces the capacity of an expansion anchor.
- Vibration-damping pads between the appliance and the support. A foundation transmits vibrations remarkably well to basement rooms.
- Checking the level on both axes before final tightening, so defrost water drains on the correct side.
The siding penetration: the detail that sets a beautiful installation apart
Drilling through a brick wall and drilling through a vinyl wall are two different operations. With vinyl, waterproofing is not achieved by applying a bead of sealant to the exterior surface—the vinyl moves, and the bead cracks within a season.
The method consists of treating the penetration beneath the siding: passing through the weather-resistant barrier, installing a sleeve, sealing it at the air barrier, then reinstalling the vinyl panel over it, with a flat mounting block if necessary. The result is a penetration that remains watertight even when the siding expands.
The appliance: GREE FLEXX ULTRA R32, 3 tons
The FLEXX series, distributed in Quebec by Dettson, is a horizontal (side-discharge) airflow central system powered by 24 VAC and controlled by a conventional thermostat. The configuration installed in Sorel-Tracy:
- Indoor unit: GUD36AH2/G-D(U)
- Outdoor unit: GUD36W2/NhE-D(U)
- Rated capacity: 34,000 BTU/h in cooling and 34,000 BTU/h in heating
- Modulation range: 18,000 to 37,000 BTU/h
- Efficiency: 18 TRES2 (SEER2), 12 TREAT2 (EER2), 10 CPSC2 (HSPF2), COP 3.2
- AHRI number : 217120760
- ENERGY STAR certification
- Heating range: down to -30 °C; cooling range: -15 °C to 54 °C
- R32 refrigerant, 2.9 lb factory charge, factory charge covering 24.6 ft of piping, add 0.32 oz per foot beyond that
- Maximum piping length: 98.4 ft; maximum elevation difference: 49.2 ft
- Diameters: liquid 3/8 in., gas 3/4 in.
- Electrical: 208–230 V, MCA 5.3 A on the indoor side, MCA 27.7 A and MOCP 30 A on the outdoor side
- Outdoor unit: 39 x 37 13/16 x 14 2/3 in., 187.5 lb, 1/6 HP fan motor
- Indoor unit: 21 1/4 x 48 1/5 x 21 1/4 in., 163.1 lb
- Factory-installed A2L leak detection sensor and Wi-Fi
The 14 2/3 in. depth is what makes this chassis compatible with a narrow yard: the unit does not extend onto the paver walkway, and the passage remains usable.
R32 and A2L labeling
R32 is classified as A2L, slightly flammable. The FLEXX includes a leak detection sensor whose position depends on the indoor unit's discharge direction: a horizontal-flow unit can be configured for left or right discharge, and a field conversion without repositioning the sensor renders the protection ineffective. We verify the position and test the shutdown logic during commissioning. The factory-applied A2L labels remain in place.
The costliest mistakes around an outdoor unit
- Move the gutter extension and forget about it. This is the only maintenance task the homeowner must perform themselves, and it is the one that best protects the unit.
- Place the unit directly on the soil of a landscaped area. The ground shifts, the unit tilts, and drainage stops.
- Plant anything or let anything climb within two feet. What is small at installation will no longer be small by the third summer.
- Washing the coil with a high-pressure jet. The fins will not straighten themselves.
- Ignoring a nearby wall exhaust outlet. A source of moisture directed toward the coil multiplies defrost cycles throughout the winter.
Rebates
The Chauffez vert program ended on March 31, 2026, and applied only to conversions from heating oil and propane. Hydro-Québec's LogisVert program remains the main source of assistance for a central heat pump: an ENERGY STAR unit with a valid AHRI number corresponding exactly to the indoor/outdoor pair actually installed, a contractor holding an RBQ licence and registered with the program, and an application submitted within the required period after the invoice. The assistance is paid as a reimbursement, and the amounts depend on the equipment and configuration. The combination installed here bears AHRI number 217120760.
Maintenance adapted to a damp site
At a site like this, we add two points to the annual HVAC maintenance service: inspecting the bottom of the coil and the base, where gutter sediment accumulates, and checking the anchors and pads in the foundation. Everything else — pressures, superheat, subcooling, airflow, electrical connections, and indoor filters — remains part of the usual program.
Why we go as far as Sorel-Tracy
At AirGreen, we install central heat pumps, wall-mounted heat pumps, mini-split systems, air conditioners, and heat-recovery ventilators in Montreal, Laval, Longueuil, the North Shore, the South Shore, and the Bas-Richelieu area — Sorel-Tracy, Saint-Ours, Sainte-Anne-de-Sorel, Saint-Joseph-de-Sorel, and nearby municipalities.
A properly installed outdoor unit is more than a level, connected unit. It is a unit positioned with the surrounding water in mind: water from the roof, water it produces itself, and water brought to it by the air. If you are planning a central heat pump, replacing equipment, or installing air conditioning for the first time, call us: we visit your property, calculate the load, measure the ductwork, and provide you with a clear proposal showing actual efficiencies, the AHRI number, and eligibility for available rebates, already verified.
AirGreen — Air Conditioning & Heating. RBQ 5645-9605-01. (514) 316-2973