Installation of a GREE FreeMatch R32 two-head wall-mounted heat pump in Outremont (borough of Montreal)

When the piping has to rise to the ceiling, the drain cannot follow it

Outremont is Montreal's smallest borough: 3.84 km² on the north slope of Mount Royal, its name simply deriving from those who went “beyond the mountain.” Côte-Sainte-Catherine Road is its oldest route; Bernard, Laurier West, and Van Horne avenues are its commercial arteries; the Outremont Theatre, built in 1928, opened in 1929.

One detail matters more than the others for our purposes: about 2,500 buildings were erected there during the first thirty years of the 20th century, in a planned development where zoning and green spaces had already been considered. This means a residential stock built largely between 1900 and 1930 — with high ceilings, plaster walls over lath with no usable cavity, original woodwork, molded casings with projecting cornices, and practically nowhere to discreetly run a refrigerant line.

This is exactly the situation on this project, and it led to two decisions we are documenting here: a line-set cover that rises to the ceiling instead of descending, and the direct consequence of that choice — a condensate pump, because water does not rise.

The project and the selected unit

Apartment in a residential building in Outremont built in the 1920s. High ceilings, original moldings, no ductwork, electric heating retained. Two zones: an open main room connected to a glazed solarium at the rear, and a second separate zone.

Selected configuration: one 12,000 BTU/h head and one 9,000 BTU/h head, for a total of 21,000 BTU/h installed on a GWHD(30)ND6MO — the 30,000 BTU/h model in the FreeMatch range, which accepts two to four indoor units. Two ports therefore remain intentionally unused.

This is the first time we have documented this compressor on a two-head project, and the reason is neither capacity nor distance.

Technical specifications for the installed outdoor unit

The model choice is not the subject of this project—but it deserves three lines

The reasons for selecting the GWHD(30)ND6MO for a two-zone project are set out in detail in our Pierrefonds-Roxboro case study: it is the highest-performing model in the entire FreeMatch lineup at the rated point, and the first in the series to offer 25 m of elevation difference instead of 15. We refer you there rather than repeat it here.

What is specific to a 1920s Outremont building is why we are willing to leave two ports free rather than choose the smallest unit that does the job.

In a suburban home, adding a zone later costs the price of a head and a short run. In an old building with solid walls, it is not the equipment that is expensive, but the route: each additional zone means another exposed duct, another aesthetic decision in a room with moldings, and another negotiation over the routing. Choosing a compressor today that accepts four heads makes it possible to add a third zone simply by running one more line along an already planned route, instead of installing a second complete system with its own outdoor unit, its own circuit, and its own building-envelope penetration. In a building where the available outdoor locations can be counted on one hand, that argument carries more weight than the specification sheet.

Two notes to close. The installed indoor capacity ratio is 21,000 out of 30,000 BTU/h, or 70% in heating mode—the diversity factor that explains why such a ratio is not unusual is discussed in detail in our Saint-Denis-sur-Richelieu case study, as is the interpretation of the minimum–maximum ranges in those for Dorval and Baie-D'Urfé. And one detail the specification sheet does not emphasize: the GWHD(30)ND6MO is the only one of the five models whose nominal capacities differ between the two modes—28,400 BTU/h in cooling versus 30,000 in heating. Everywhere else in the lineup, the two figures are identical.

What this choice really costs

Higher efficiency does not come for free, and we state that in the quotation:

• 66 kg instead of 51 or 35.5, and a 1020 × 826 × 427 mm cabinet. The outdoor location and its base must accommodate it.
• 62 dB(A) at high speed compared with 54 for the 18,000 model. On Outremont's tight lots, this is a real concern, and the attenuation mechanism with distance is explained in our Huntingdon report.
• 35 A MOCP instead of 20 or 25. In an older building, the electrical panel is often the limiting factor, and load calculations must be performed by a master electrician.
• 2,200 g of R32 instead of 1,700. Because R32 is an A2L refrigerant, the minimum room area listed on the nameplate is based on the total charge: the smallest room must be checked again after the final length calculation. The mechanism is detailed in our Dundee and Sainte-Martine reports.
• Two ports left unused, which is an advantage for the future but a cost today.

Why the piping was routed along the ceiling

In the photo, the line set cover exits from the right side of the head, curves upward, reaches the ceiling, and then runs horizontally along it. This is not an aesthetic choice: it was the only route that remained.

Three reasons, in the order in which they became clear during the technical inspection:

1. A 1920 lath-and-plaster wall offers no usable cavity. There is nothing to open and then close cleanly, and we do not drill blindly into irregular lathwork. This is also why the exposed route exists: we covered drilling through old plaster in our Napierville report, and the deliberate use of an indoor line set cover as a solution in our Saint-Louis-de-Gonzague report.
2. The head is installed above a molded cornice door casing. There is no straight exit toward the rear at that location, and the molding prevents a clean vertical drop.
3. The exit point to the outside was at the top, not the bottom. As soon as the line had to rise, it rose immediately rather than zigzagging.

A ceiling-mounted line set cover is not a wall-mounted line set cover

We published the four quality markers of an indoor line set cover — sizing, bend radius, drain slope inside the cover, and insulation joints — in our Saint-Louis-de-Gonzague report, where the risk of condensation inside a line set cover is explained in detail. What changes when the route runs along the ceiling deserves to be added:

• The 90° upward elbow is the critical point in the route. A copper line pinched in a tight bend cannot be seen from outside the line set cover and cannot be fixed afterward. The bend radius must be respected, even if that means widening the curve and accepting its visual presence — that is exactly what the photo shows.
• Support spacing is tightened on the ceiling. A wall-mounted raceway is partly supported by gravity; on the ceiling, everything puts tension on the fasteners, and a section that sags between two supports creates a low point where condensation can accumulate.
• A ceiling line is visible from everywhere in the room. A wall run can be concealed behind a piece of furniture; a ceiling run cannot. It must therefore be aligned with an existing line in the room—wall edge, cornice, or wall-ceiling junction—rather than cutting diagonally across the surface, and this decision must be made with the client before the work, not during it.
• Finish painting is not our responsibility, and we say so before starting. Our Saint-Bernard-de-Lacolle case file specifies this; a raceway can be painted very well, but that is a painter's job, after we leave.

The wall above a molded door or window casing

Only two points, because the subject is covered extensively elsewhere in our case files. The cornice of a door or window casing is not the ceiling: clearance above the casing is measured to the nearest obstruction, and a projecting molding creates a shelf above the return grille—we covered this in Dorval. And the structural lintel above an opening must not be drilled: the plate must find actual solid wood, never an applied molding, as explained in Verchères and Havelock.

A 1920 ceiling is higher, and the building is less airtight

Installation height as a design variable is covered in our Saint-Polycarpe case file, stratification in the one on Saint-Amable, jet throw in the one on Sainte-Martine, and access to high-mounted filters in the one on Saint-Lazare. What we add here can be summed up in one sentence, but it is important.

In a recent construction with nine-foot ceilings, stratification exists, but the building envelope contains it. In a 1920 building, the high ceiling comes with a less effective envelope: warm air rises, and the cold surface above encourages it to rise further; the difference between the layer beneath the ceiling and the occupied zone is greater than in a new home of the same height. The head's return-air sensor, which reads the air drawn in at the top of the casing, is therefore even more optimistic in heating mode. We consequently increase the minimum ventilation speed for this zone by one setting during commissioning, and the baseboard heaters remain in service.

The condensate pump: the only component that can flood a home

In the photo, a small white box is mounted on the wall just below the head. It is not a decorative accessory: it is a condensate pump, and it is there because the piping rises.

Our position on the principle has not changed and can be found in our Cèdres case study: gravity first, always. A drain that slopes downward on its own needs no power supply, float, reservoir, or moving parts. It never fails. When possible, gravity wins—and our Sainte-Julie case study explains why we even preferred it for noise-related reasons in an office.

Here, it was not possible. A head installed high on an interior wall, with its line running toward the ceiling, has no downward path to the outside. The choice therefore is not between a pump and gravity: it is between a pump and moving the head elsewhere in the room. Both options were priced, and the decision belonged to the client.

What fails, and what it means

This is the part nobody publishes, and it is what matters to a homeowner who will live with the unit for fifteen years. A condensate pump is a small motor, a float, and a reservoir. In this order of frequency, here is what we encounter during service:

1. The reservoir gets fouled. The head's basin and the pump reservoir remain damp throughout the air-conditioning season, allowing a biofilm to form—the mechanism is the same as the one described in our Sainte-Marthe case study for the coil. A fouled reservoir eventually prevents the float from dropping or rising.
2. The float gets stuck. This is almost always the consequence of the previous issue, and it is the most dangerous failure mode, because a float stuck in the down position never asks the pump to start.
3. The check valve wears out. Water flows back into the reservoir every time the pump stops, so the pump restarts more often than necessary and its wear accelerates.
4. The motor fails. This is the rarest and most visible failure mode.

A pump is a wear item, not a lifetime component. It will need replacing, and it can be replaced easily if it can be reached.

Where to install it: access determines everything

This is the most important installation decision on the entire project, and it must be made before securing the plate.

• The pump remains accessible without dismantling the unit, without acrobatic ladder work and without opening a wall. A pump hidden behind a closed cabinet is a pump that will never be serviced.
• It is installed level, and its reservoir can be removed for cleaning without disconnecting the discharge line.
• The safety float is wired to stop the head when the level is high, not to sound continuously. The logic behind this connection, together with the check valve and vibration-damping mounts, is published in our Saint-Michel case study.
• The discharge line must never be connected to a shared gravity-drain line used by another head unit. The reason is explained in Les Cèdres, and it is worth remembering: a pump also pushes upstream.
• The place where the water ends up must be chosen as carefully as the place it leaves from—never above a passageway, never against the foundation, and never near the outdoor unit.

The sound of a pump at night in a living area

A condensate pump does not run continuously: it starts in short cycles whenever the reservoir fills. In the middle of a heat wave, for a head unit that removes a great deal of humidity, this can mean several starts per hour.

The sound is brief and mechanical, and it is precisely its intermittent nature that makes it noticeable: continuous noise fades into the background, but a click that returns every few minutes does not. In a bedroom, it is unacceptable; in a high-ceilinged living area where the sound reflects off hard surfaces, it should be disclosed before installation rather than discovered on the first night of July. We place the pump as far as possible from resting areas, on a mounting that does not transmit vibrations into the partition, and we warn the client about what they will hear.

The maintenance schedule, and what happens when it is ignored

A condensate pump adds a line to the maintenance checklist, and it is an addition, not a replacement:

• Rinse the filters of each head according to the season of use.
• Cleaning the pump reservoir and checking that the float moves freely once a year before the cooling season. This is the task homeowners overlook, and it is the one that prevents the most costly failure.
• Functional test of the safety float at every maintenance visit: we verify that it actually shuts down the head unit; we do not assume that it will.
• Pouring-water drainage test, because indoor drains produce nothing in heating mode and a defect can remain dormant all winter.

Regarding the consequences of a failure, we stick to the facts and we are not brokers: water damage related to a condensate drain is by far the most frequent claim involving a heat pump, and it is resolved based on documented facts—installation date, contractor's licence, commissioning records, and maintenance history. We have explained what this entails in our Très-Saint-Rédempteur case file, and we invite every client to review their own policy.

Errors to avoid

• Accept a pump when gravity drainage was possible. The question must be addressed before securing the plate, not afterward.
• Place the pump somewhere inaccessible because we did not want to see it.
• Do not connect the safety float to the head unit shutdown.
• Connect a pump discharge to a shared gravity-drain line.
• Forget the tank in the maintenance schedule.
• Tighten the copper bending radius at the line-set cover’s upward elbow to gain a few centimetres.
• Space the supports of a ceiling-mounted line-set cover the same way as those of a wall-mounted line-set cover.
• Choose a 30,000 BTU/h compressor without checking the electrical panel (MOCP 35 A) or the outdoor location (66 kg, 62 dB(A)).
• Drill through a lintel or surface-mounted trim to install the plate.

Commissioning, rebates, and warranty

Standard protocol: deep vacuum with a rise test, weighed additional charge at 20 g/m beyond the 40 m factory charge, recorded in the file; functional testing of one head at a time in both modes; readings at each port; drainage testing of every pan and testing of the pump’s safety float before closing anything up; and a written note of the estimated balance point. Installed lengths, serial numbers matched to their rooms, the circuit number at the panel, the pump location, and AHRI number 214931588 for the installed combination are provided to the owners.

Because the home is heated with electricity, Chauffez vert does not apply—this program is intended for converting from fossil fuels. Hydro-Québec’s LogisVert and Rénoclimat are the programs to consider, and the declared AHRI number must match exactly the combination actually installed. Requirements change, so we verify them when opening the file rather than publishing outdated amounts.

The warranty is 10 years, extended to 12 years when registered with the distributor and accompanied by proof of installation. A condensate pump, on the other hand, is a wear item whose maintenance affects its service life—and that is explained before the sale.

We install throughout Greater Montreal

At AirGreen, we design, install, and maintain HVAC systems in Montreal—Outremont, the central part of the island, and neighboring boroughs—as well as in Laval, Longueuil, on the North Shore, and on the South Shore. As a licensed, insured RBQ contractor, we document our work: the agreed-upon line-set cover route before work begins, piping lengths recorded in the file, the pump’s location and model documented, and commissioning parameters recorded for each room.

In an older building, the equipment itself isn’t the difficult part: it’s the route the copper and water must take. Ask us for an on-site assessment for your wall-mounted heat pump, wall-mounted air conditioner, or HVAC maintenance—we map out the route before drilling the first hole.