Twenty-five feet of pipe: the part of the installation that no one photographs, and the part that determines everything else
The photo of this project in Saint-Valérien-de-Milton, in the Maskoutains RCM, was taken from behind the unit. It is an angle contractors avoid: it does not showcase the condenser's attractive front; it shows service panels, warning labels, and piping.
That is exactly why it is worth examining. Everything that distinguishes a carefully executed installation from a rushed one is found on this side: the refrigerant line, its insulation, its protection, its passage through the wall, and the service valves to which a technician will connect ten years from now.
The project
A townhouse with vinyl siding, a bed of crushed stone along the foundation, a mature blue spruce less than three feet away, and a 5-ton GREE UNIX R32 central heat pump mounted on a strut support above the stone bed.
The indoor unit—an UNIX R32 air handler—is located in the basement. The refrigerant line therefore runs up along the exterior wall, passes through the siding at a high point, then descends indoors. This seemingly ordinary geometry requires several checks.
The line length, in figures
The UNIX R32 series comes with a standard piping length of 24.6 ft covered by the factory charge. Two limits frame the installation:
- Maximum piping length: 98.4 ft
- Maximum elevation between units: 49.2 ft
These two figures are not suggestions. Exceeding the maximum length means accepting a loss of capacity and uncertain oil return to the compressor. Exceeding the maximum elevation means asking the refrigerant to rise up a column that the system is not designed to overcome.
On this project, the route stayed well within both limits. We still measured it and recorded it in the file, because it is the first piece of data a manufacturer requests when a unit behaves poorly, and because the technician who comes eight years from now will have no way to reconstruct it.
The most common mistake: insulating only one line
This is the central technical point of this article, and it applies to all central heat pumps, regardless of brand.
On a conventional air conditioner, the usual practice is to insulate the large suction line and leave the small liquid line bare, often taped against the first. This practice is acceptable for a unit that only cools.
On a heat pump, it is not.
A heat pump reverses its cycle. In heating mode, the large line 3/4 po carries hot gas indoors, while the 3/8 po carries cold liquid back outdoors. If the two pipes are stuck together with no insulation between them, they exchange heat with each other. What the hot line loses, the cold line gains, and the house gets neither. The loss is silent, continuous, and invisible on a utility bill.
On this job, the two lines are insulated separately along their entire length, including the bends and all the way to the connections. It takes longer to do. It is the difference between a unit that delivers the figures in its technical specifications and one that delivers 90% of those figures.
The sun, rain, and rodents
An outdoor refrigerant line remains outdoors for fifteen years. Three hazards destroy it.
Ultraviolet rays
The black foam insulating the lines degrades in sunlight. It turns white, hardens, cracks, and then disintegrates into pieces. Once the foam is gone, the bare gas line loses heat in winter and becomes covered in condensation in summer.
Protection is provided in two ways, often combined: UV-resistant wrapping, visible in the photo, and a rigid cover installed over the most exposed section. On this wall, which faced the late-afternoon sun, both were justified.
The wall penetration
The passage through the siding is made with a sleeve and a finishing piece, not through a randomly drilled hole filled with foam. On vinyl siding, the seal must be made under the panel, at the air-sealing plane, never with a bead of sealant applied to the exterior surface: vinyl expands by several millimeters between January and July, and the sealant cracks within the first year.
Rodents
This is a rural reality that HVAC articles ignore. In a row of homes in Montérégie, with fields nearby and a bed of crushed stone along the foundation, mice look for an entry point in the fall. Refrigeration-line insulation foam is easy to gnaw through, and a poorly sleeved penetration is an open door. A tight sleeve and continuous wrapping close off both opportunities.
The service valves and their red caps
In the photo, two red caps cover the service valves at the back of the unit.
The UNIX R32 series deliberately places its service valves and electrical terminals outside the chassis. This design choice saves considerable time during both installation and maintenance: the connections can be accessed without removing panels.
These caps are not decorative. They form the second sealing barrier in the circuit, after the valve core. A cap left loose, lost, or replaced with tape is a slow leak in the making—and with an A2L-classified refrigerant, a slow leak is not an inconvenience; it is a deficiency. We tighten them to the prescribed torque and check that they are present during every annual HVAC maintenance visit.
The nameplate
The unit's nameplate is always at the back. We systematically photograph it at the end of the job and attach the image to the customer's file, along with the barcodes and serial number.
This is the document that settles, without debate, a warranty question, a rebate application, or a parts order eight years later. A unit with an unreadable or inaccessible nameplate costs everyone hours.
The unit and what it brings to a townhouse
GREE UNIX R32, 5 tons, in air-handler cabinet configuration
- Indoor unit: GUD60AH2/G-D(U) — Outdoor unit: GUD60W2/NhE-D(U)
- AHRI code : 217120762
- Cooling capacity : 53,000 BTU/h (35 000 – 55 000)
- Heating capacity : 54,000 BTU/h (35 000 – 60 000)
- SEER 2: 18.5 — EER 2: 11.7 — HSPF 2: 10.5 — COP at 8 °C: 3.40
- Airflow: 1,500 cfm — nominal external static pressure: 0.5 in. w.c.
- Operating temperatures: heating from -30 °C to 24 °C; cooling from -15 °C to 54 °C
- R32 refrigerant, 4.6 kg charge
- Lines: suction 3/4 in, liquid 3/8 in
- Electrical: 208–230 V / 60 Hz / single-phase — indoor MCA 7.7 A, MOP 15 A; outdoor MCA 39.9 A, MOP 45 A
- Indoor cabinet: 24 13/16 x 51 31/32 x 21 17/64 in, 199.5 lb
- Outdoor unit: 35 25/64 x 49 19/32 x 13 25/64 in, 241.4 lb, 62 dB(A)
- Two-stage, twin-cylinder compressor, DC Inverter technology
- Integrated refrigerant leak detector, compatible 24 VAC thermostat and RS485 communication
One detail deserves emphasis: with 10.5 HSPF 2, this configuration delivers the best seasonal heating efficiency of the entire UNIX R32 series. In a home heated for eight months of the year, this is the rating that matters most—more than SEER 2, which only applies to summer.
Ultra Heat: 100% capacity at -20 °C
The specifications state 100% of heating capacity at -20 °C and stable operation down to -30 °C.
The distinction is essential and rarely explained. Many units “operate” at low temperatures: they run, but their capacity has collapsed and the auxiliary heat operates continuously. Maintaining full capacity at -20 °C means delaying the changeover to backup heat by several hundred hours per season—and that is where the real savings are found, not in the efficiency rating displayed at +8 °C.
The home's balance point, calculated from the heating load, determines the exact changeover temperature. It is a setting, not an intuition, and it is configured during commissioning.
The disconnect switch and power supply
The disconnect switch is installed on the wall, within sight of the unit, as shown in the photo. The outdoor circuit is dedicated and complies with the 45 A MOP, with a minimum ampacity of 39.9 A.
In a row house, this calculation is done before the sale. Between the electric backup heat, water heater, and often a well pump, the electrical service is frequently more heavily loaded than in an urban area, and a 5-ton unit does not fit everywhere.
Mistakes to avoid on a refrigeration line
- Insulating only the suction line. On a heat pump, both lines must be insulated separately.
- Leaving the foam exposed to sunlight without wrapping or a cover.
- Drilling without installing a sleeve and sealing from the outside on vinyl siding.
- Failing to measure the actual length of the run or record it in the file.
- Neglecting the valve caps, which are part of the circuit's seal.
- Running the line against the wall without support, transmitting compressor vibrations into the structure.
Rebates
The Chauffez vert program ended on March 31, 2026. Hydro-Québec's LogisVert program remains the primary source of assistance for a central heat pump: eligibility is based on the exact installed indoor/outdoor pairing and its AHRI code — here, 217120762 — on a contractor holding an RBQ licence and registered with the program, and on an application submitted within the required period after the invoice. We validate the combination before signing.
Why we travel to the rural concessions of Saint-Valérien-de-Milton
At AirGreen, we install central heat pumps, wall-mounted heat pumps, mini-split systems, air conditioners, and air exchangers in Montreal, Laval, Longueuil, the North Shore, the South Shore, and the agricultural municipalities of Montérégie — Saint-Valérien-de-Milton, Sainte-Cécile-de-Milton, Saint-Dominique, Roxton Pond, and the rural concessions around Saint-Hyacinthe and Granby.
The condenser is the visible part of the work. The refrigerant line is what determines whether the unit will deliver its rated performance for fifteen years. If you are planning a central heat pump, an equipment replacement, or your first air-conditioning installation, call us: we come to you, calculate the load, measure the ductwork, and provide a clear proposal with actual performance figures, the AHRI code, and eligibility for available rebates already validated.
AirGreen — Air Conditioning & Heating. RBQ 5645-9605-01. (514) 316-2973