Installation of a GREE FreeMatch R32 2-head heat pump in Saint-Basile-le-Grand (La Vallée-du-Richelieu RCM)

The eight-dollar pipe that causes water damage: the condensate drain

The city's name is confusing, and the Commission de toponymie corrects it itself: although the name refers to Saint Basil the Great, bishop of Caesarea, it is “rather a humble farmer, Basile Daigneault680 inhabitants. It had 17,053 in the 2021 census, across 35.8 km², of which nearly seven out of ten homes are detached single-family houses — and not a single building of five storeys or more.

This is a residential area where the wall-mounted heat pump is the default way to add comfort. And it is an area where the same call comes back every summer: water is leaking from the wall.

Almost never because of the unit. Almost always because of the drain.

The project in brief

What a wall-mounted head actually produces in summer

In air conditioning, a wall-mounted head does more than cool: it dehumidifies. Room air touches a coil colder than its dew point, moisture condenses on it, runs into a shallow pan beneath the heat exchanger, and leaves through a flexible pipe to the outside — by gravity, along its entire length.

A single head can produce several litres per day on a humid day. This is not an insignificant trickle: it is a continuous flow through a small-diameter pipe, with a slight slope, passing through a wall.

Nothing pushes the water through it. There is no pressure, pump, or strong gravity. This is the structural weak point of any wall-mounted unit, which is why the drain is the most ordinary and most costly part of the installation.

Why a drain gets clogged

Four causes, in the order in which we encounter them.

The biofilm. A pipe that is warm, permanently damp, and dark is a breeding ground. A biological film slowly develops inside it, breaks off in patches, and forms a clog at the first restriction—a bend, a fitting, or a low point.

Dust that passes through the filter. Fine particles that reach the coil are captured by condensation and washed into the pan. They mix with the biofilm. It's this mixture, not either one alone, that causes the clog.

The lost slope. A pipe must slope downward continuously, with no reverse slope, along its entire length. A clamp that's too tight, sagging between two support points, or a retrofit made to go around an obstacle: a belly only a few centimetres deep is enough to create a reservoir of stagnant water—and a starting point for the clog. We published the verification of the continuous slope before fastening the panel on our Saint-Étienne-de-Beauharnois page; it's the only reliable way to ensure it, because once the unit is installed, no one can see the pipe anymore.

The outdoor outlet. The end that opens outside is a warm, damp opening into the inside of a wall. Insects, wasps, and spiders settle there. And an end that dips into gravel, soil, or a garden bed eventually starts drawing in whatever surrounds it.

What happens when it clogs

The pan overflows. It is shallow—it has no reserve capacity. The water spills over, runs behind the unit, and then descends into the wall.

This is where the problem changes nature. It's no longer an HVAC problem: it's water damage in a finished wall, often discovered weeks later by a stain on the ceiling of the floor below or a baseboard that has warped.

The warning signs, in order:

1. A gurgling sound that comes and goes in the unit. It's air rising through a partially blocked pipe.
2. A trickle of water that appears and then disappears in very humid weather—the pan overflows only during peak production.
3. An odor of damp earth or mildew when the system starts.
4. Nothing at all outside. The absence of drainage at the outlet on a scorching-hot day is the most reliable signal of all—and the only one the homeowner can check themselves, without tools, in thirty seconds.

Look at your unit’s drain outlet during a hot, humid day. Water should be coming out of it.

What we do during installation, and what we do not do

During installation: the route is laid out before drilling, continuous slope is verified with an instrument rather than by eye, supports are spaced closely enough to prevent any sagging, no reverse slope is tolerated, the exterior end is kept clear of the ground, and the tray and entire run are tested with water before anything is closed up. The wall is not closed over a drain that has not flowed in front of us.

What we do not recommend, despite what is circulating: pouring bleach into the tray. A tray and a coil contain aluminum and copper, and hypochlorite attacks both. A condensate circuit should be cleaned with products designed for that purpose, or mechanically, by suction from the exterior outlet — the technique we had detailed at Saint-Sébastien. An improvised unclogging that corrodes the heat exchanger turns a service call into unit replacement.

When there is a condensate pump

When gravity drainage is insufficient — a basement, an interior wall, an outlet higher than the unit — a condensate pump takes over. It is one more mechanical component, with its own failure modes: fouled float, colonized reservoir, worn check valve.

Two rules we apply without exception. The customer is warned before installation that a pump makes noise — cyclically, at night as well as during the day. And we never combine gravity drainage and a pump on the same run: that is the Cèdres rule, and it exists because the transition point becomes the blockage point.

The City of Saint-Basile-le-Grand says itself where the problem lies: in the installation

Here is something few municipalities put in writing, and Saint-Basile-le-Grand does.

On its page dedicated to noise, the City sets quantitative thresholds, measured at the property line from which the noise originates: emissions exceeding 60 dB(A) during the day, between 6 a.m. and 9 p.m., or 55 dB(A) at night, between 9 p.m. and 6 a.m., are prohibited, with the general clause that “the emission of any noise disturbing the peace or tranquility of the neighborhood” constitutes a nuisance.

And above all, the City identifies heat pumps and air conditioners as sources of neighbour disputes, specifying that an installation of these appliances that does not comply with the rules is the cause of noise emissions. The appliance itself is not being blamed. It is the way it was installed.

Two honest clarifications. The City's page itself states that it is a simplified version that does not replace the official documents, and it cites no section number; we therefore report these thresholds as published by the City, without attributing them to a numbered section. And a reminder that applies everywhere: the decibels on a technical specification sheet and those in a regulation are not the same measurement—one is measured at a short distance in a laboratory, while the other is measured at the property line in the real world. Our Saint-Jean-sur-Richelieu page explains this distinction in more detail.

The certificate of authorization—and the four to six weeks no one mentions

The City lists “accessory equipment (cylinder, heat pump, outdoor fireplace)” among the work requiring a permit or certificate. A certificate is therefore required to install a heat pump in Saint-Basile-le-Grand.

And the same page states a processing time of four to six weeks.

Remember this figure, because it changes everything when planning a project. A homeowner who calls in June to have air conditioning installed in July will not get it. A contractor who promises installation “next week” in Saint-Basile-le-Grand in June has not submitted an application—or is counting on no one checking.

Contractor or installer: the four things to check

Since the City identifies the installation as the cause, here is what concretely distinguishes the two in Quebec, regardless of opinion:

1. The RBQ licence, with the subcategories corresponding to the work. It can be verified online, in thirty seconds, in the Régie du bâtiment registry. A number that does not appear in the registry, or whose subcategories do not cover the work, is merely decorative.
2. The environmental qualification certificate for halocarbons. In Quebec, only a person who holds this certificate may install, maintain, repair, or dismantle equipment designed to operate with a halocarbon—and only a certificate holder may purchase refrigerant. This is not a mark of prestige; it is a legal condition for accessing the fluid.
3. The electrical connection. The dedicated circuit, disconnect, and wire gauge fall within the electrician's trade. For this GWHD(30), it is MCA 23 A and MOCP 35 A — values that belong in the calculation, not the estimate.
4. The municipal certificate. Requested, obtained, and filed. See the four to six weeks above.

A quote that is significantly lower than the others is almost always missing one of these four lines. The question to ask is not “why are the others more expensive,” but “which of these four items is not included?”

What we will not publish about Saint-Basile-le-Grand

The City's planning by-laws — U-220 (zoning), U-210 (permits and certificates), 552 (nuisances) — could not be consulted: the files are inaccessible to automated reading. We therefore have no verified setback in metres, no verified permitted or prohibited yard, no verified screening requirement, and no verified maximum height for a heat pump in this city.

It would be easy to write that the front yard is prohibited, because that is the case in several neighbouring municipalities. We will not write that: what is true in McMasterville is not automatically true here, and the silence of a by-law we have not read authorizes nothing.

The reliable route fits in one line: Urban Planning and Environment Department, 204 Principale Street, 450 461-8000 ext. 8400, Monday through Thursday and Friday morning. A call settles in five minutes what no blog post can determine.

The selected unit

Two wall-mounted heads, 18,000 and 12,000 BTU/h, for a total of 30,000 BTU/h — exactly the GWHD(30)'s rated heating capacity. We openly point out that this is a configuration already published in this series: it is the suitable pairing, not a new release.

A useful point for anyone comparing quotes: the GWHD(30) is the most efficient model in the entire FreeMatch range, the only one to exceed 4.0 in both EER and COP. The larger GWHD(36) drops back to 3.52 and 3.56. Moving up in capacity comes at the cost of efficiency.

The sizing of the indoor unit also matters for the drain, which closes the loop: an oversized unit cools quickly, stops, and dehumidifies poorly — it produces short, humid cycles instead of continuous drying. Perceived comfort depends on it just as much as temperature does.

Mistakes to avoid

• Never checking the drain outlet. Thirty seconds each summer is enough.
• Pouring bleach into the pan or onto the coil.
• Accepting a drain installed without a water test before closure.
• Leaving the outdoor end submerged in soil or mulch.
• Combining gravity drainage and a pump along the same route.
• Planning an installation without allowing for the four to six weeks required to process the certificate.
• Comparing quotes without checking which one includes the licence, refrigerant-handling certificate, electrician, and permits.

Rebates, service area, and support

These units are eligible for local rebates, and the AHRI codes above are required by the programs. We support every application for LogisVert, Rénoclimat, and Chauffez vert, entering the codes in the end-of-project file — without promising amounts whose eligibility criteria are outside our control.

In the La Vallée-du-Richelieu RCM, we have documented installations in Belœil, Mont-Saint-Hilaire, and Otterburn Park. Carignan, Saint-Bruno-de-Montarville, Sainte-Julie, McMasterville, and Chambly complete the area. Our teams cover Montreal, Laval, Longueuil, the North Shore, and the South Shore.

Why AirGreen

The City is right: what distinguishes two installations that look identical is what was done before the wall was closed. At AirGreen, the drain is mapped out before drilling and tested with water before closure, the municipal certificate is requested at the beginning of the project rather than at the end, and we quote the regulations without interpreting them — even if, as here, that means writing that we were unable to read them.

For an assessment in Saint-Basile-le-Grand, write to us: we measure before making recommendations.