York Sunline WN Packaged Heat Pump Rooftop Unit – Supplied & Professionally Installed by 4Most Energy
The York® Sunline WN Series is a factory-assembled, single-package heat pump rooftop unit built for small commercial buildings in the 3 to 5 nominal ton range. It delivers up to 13.4 SEER2 cooling and 6.7 HSPF2 heating from one factory-charged cabinet, with R-454B refrigerant, micro-channel aluminum condenser coils, and the Smart Equipment™ control board with on-board diagnostics and USB data logging standard on every WN036 through WN060 model. A scroll compressor and built-in low-ambient control allow cooling operation down to 0°F outdoor ambient. Heating is rated at 3.00–3.35 COP at 47°F, dropping to 2.05–2.2 COP at 17°F, at which point field-installed nickel chromium electric heat (5 to 30 kW) engages as backup. Full-perimeter base rails, forklift slots, and a shared cabinet footprint across all three sizes simplify rigging, curb selection, and future service — and with no on-site combustion, the Sunline WN is a straightforward path to building electrification.
Rated performance depends entirely on correct field installation. Ontario installations require ESA-compliant electrical hookup sized to the unit's MCA/MOCP rating, which varies meaningfully by voltage (208/230-1-60, 208/230-3-60, 460-3-60, or 575-3-60) and electric heat kW selection, along with refrigerant charge verification on a mildly flammable (A2L) R-454B circuit and correct heat pump/electric heat changeover setup. Roof curb selection (8 in. or 14 in. NRCA-approved curbs), structural load review, and sealed duct connections at the unit's bottom or horizontal openings are equally code-driven and equally easy to get wrong without an experienced crew. 4Most Energy handles packaged heat pump installation in Toronto, packaged rooftop replacement across the GTA, and York Sunline WN installation projects throughout Ontario — so the SEER2 and HSPF2 figures on the nameplate are what the building actually gets, not just what's on the spec sheet.
Replacement Option
The York® Sunline WN Series shares a common roof curb across every size in the line, and — using an appropriately sized curb adapter to bridge differing roof curb and duct footprints — it can replace aging Trane, Lennox, Daikin, Rheem, and AAON packaged heat pump or straight-electric units of comparable tonnage. This lets 4Most Energy convert a building to a modern, low-GWP, all-electric rooftop heating and cooling solution without necessarily requiring a full roof curb and structural rework, minimizing both project cost and rooftop downtime.
Warranty
York backs the Sunline WN Series with a 1-year limited warranty on the complete unit, a 5-year limited warranty on the compressor, and a 5-year limited warranty on factory-installed electric heater elements (when equipped). 4Most Energy handles warranty registration and start-up documentation on your behalf.
Documents
Why Install the York Sunline WN with 4Most Energy?
- R-454B refrigerant with micro-channel coils a lower-GWP alternative to legacy R-410A, paired with micro-channel aluminum condenser coils for improved heat transfer and a reduced refrigerant charge.
- Smart Equipment™ control board embedded LCD display, on-board USB port for data logging and software updates, on-board diagnostics with fault code memory, and compatibility with a standard thermostat, zone sensor, or BACnet MS/TP, Modbus, and N2 building automation protocols.
- Heat pump heating with electric backup 6.7 HSPF2 rating with field-installed nickel chromium electric heat elements (5 to 30 kW, single or two-stage) providing supplemental capacity in low-ambient conditions.
- Optional refrigerant detection system (RDS) factory- or field-installed sensors provide R-454B leak detection and automatically dilute refrigerant gas while alarming the control board.
- Low-ambient operation to 0°F integrated low-ambient control allows cooling operation down to 0°F outdoor ambient without additional field-installed accessories.
- Anti-short cycle and nuisance-trip protection programmable minimum run times and a “three times, you're out” lockout philosophy on high/low-pressure switches and freezestats reduce false service calls.
- Convertible airflow design factory-covered duct openings convert between bottom and horizontal discharge without additional accessory panels.
- Full-perimeter base rails permanently attached, with forklift access from three sides and rigging holes for overhead crane placement.
- Factory-installed economizer options dry bulb or dual enthalpy economizers with AMCA 511 Class 1A low-leak dampers, capable of introducing up to 100% outdoor air for free cooling.
- Shared cabinet footprint all three sizes (3 to 5 tons) use the same cabinet and roof curb, simplifying future capacity changes or multi-unit sites.
Sunline WN Specifications
| Model | Nominal Tons | Net Cooling (Btu/hr) | SEER2 | EER2 | Heating at 47°F (Btu/hr) | COP at 47°F | HSPF2 | Sound (dBA, AHRI 270) | Operating Weight (lb) |
|---|---|---|---|---|---|---|---|---|---|
| WN036 | 3.0 | 38,000 | 13.4 | 11.4 | 36,000 | 3.30 | 6.7 | 83 | 610 |
| WN048 | 4.0 | 47,000 | 13.4 | 11.2 | 44,000 | 3.00 | 6.7 | [INSERT DATA] | 616 |
| WN060 | 5.0 | 56,000 | 13.4 | 10.2 | 52,000 | 3.35 | 6.7 | 88 | 620 |
Net cooling capacity and SEER2/EER2 rated per AHRI Standard 210/240; cooling sound ratings per AHRI Standard 270. All models share the same
82-1/4 in. L × 44-7/8 in. W × 32-5/8 in. H cabinet footprint and roof curb.
| Low-Ambient Heating (heat pump output at 17°F) | WN036 | WN048 | WN060 |
|---|---|---|---|
| Heating at 17°F (Btu/hr) | 21,000 | 26,000 | 31,800 |
| COP at 17°F | 2.10 | 2.05 | 2.20 |
| Electric Backup Heat | 5–30 kW | 5–30 kW | 5–30 kW |
Base Unit Electrical Data (No Electric Heat)
| Model | Voltage | Compressor RLA / LRA | MCA (Amps) | Max Fuse/Breaker (Amps) |
|---|---|---|---|---|
| WN036 | 208/230-1-60 | 14.7 / 109 | 26.3 | 35 |
| WN036 | 208/230-3-60 | 12.2 / 102.8 | 20.8 | 30 |
| WN036 | 460-3-60 | 5.8 / 50 | 10.0 | 15 |
| WN036 | 575-3-60 | 4.5 / 41 | 8.0 | 15 |
| WN048 | 208/230-1-60 | 22.4 / 126 | 37.5 | 50 |
| WN048 | 208/230-3-60 | 12.8 / 120.4 | 23.1 | 30 |
| WN048 | 460-3-60 | 6.0 / 49.4 | 11.0 | 15 |
| WN048 | 575-3-60 | 5.8 / 41 | 10.3 | 15 |
| WN060 | 208/230-1-60 | 25.2 / 147.3 | 50.8 | 70 |
| WN060 | 208/230-3-60 | 13.8 / 150 | 29.1 | 40 |
| WN060 | 460-3-60 | 6.9 / 58 | 14.6 | 20 |
| WN060 | 575-3-60 | 5.8 / 47.8 | 11.9 | 15 |
Electrical data shown for base units without electric heat. 208 V and 230 V ratings are identical and shown in one row. Electric heat accessories (5 to 30 kW) substantially increase MCA and max fuse/breaker sizing — exact figures are confirmed for the selected kW and staging before finalizing the electrical design. A field-supplied and field-installed disconnect switch is required by code on all sizes.
The Sunline WN is sized first by cooling load (3–5 nominal tons) using a proper commercial load calculation — not by matching the tonnage of the unit being replaced, since older rooftop units on the same curb were frequently oversized. Because heat pump output declines as outdoor temperature drops (from 3.00–3.35 COP at 47°F to 2.05–2.2 COP at 17°F), sizing should also weigh the building's design heating load against the unit's 17°F output and the available electric backup heat capacity (5 to 30 kW) for Ontario's coldest design days. Because all three sizes share the same cabinet and roof curb, a tonnage change within the WN036–WN060 range typically does not require a new curb. 4Most Energy performs load calculation, electrical capacity verification, and curb/structural review as part of every quote before ordering.
Installation & Assessment Checklist
| Phase | Description & Key Requirements | |
|---|---|---|
| Step 1 | Site Assessment | Existing equipment inspection, electrical service review, and roof curb, slab, or steel-beam mounting evaluation. |
| Step 2 | Load Calculation & Unit Sizing | Confirm correct tonnage, electric backup heat capacity, economizer/BAS requirements, and duct configuration (bottom or horizontal). |
| Step 3 | Rigging & Placement | The Sunline WN's full-perimeter base rails, forklift slots, and rigging holes allow forklift or overhead crane placement onto the roof curb, slab, or beams. |
| Step 4 | Roof Curb & Structural Prep | Install or verify the correct 8 in. or 14 in. NRCA-approved roof curb, full-perimeter gasketing, and structural support. |
| Step 5 | Electrical Connection | ESA-compliant hookup to a field-installed disconnect switch, sized to the unit's MCA/MOCP rating for the building's voltage, phase, and selected electric heat kW. |
| Step 6 | Ductwork Tie-in | Supply and return duct connection matched to bottom or horizontal discharge, with sealed transitions. |
| Step 7 | Refrigerant & Controls Commissioning | R-454B refrigerant charge verification, Smart Equipment™ control board configuration (thermostat, zone sensor, or BAS integration), and heat pump/electric heat changeover setpoints. |
| Step 8 | Airflow & Performance Verification | Confirm airflow and heating/cooling changeover operation, with start-up documentation and warranty registration filed. |
| Step 9 | Final Walkthrough | Filter access, service clearances, and control board operation demonstrated before the crew leaves site. |
York's standard coverage on the Sunline WN Series is a 1-year limited warranty on the complete unit, a 5-year limited warranty on the compressor, and a 5-year limited warranty on factory-installed electric heater elements (when equipped). 4Most Energy completes and files the required start-up documentation to keep warranty coverage valid.
Routine maintenance is straightforward by design: hinged, tool-less filter, motor, and electrical access panels speed up inspections, and the Smart Equipment™ board's on-board diagnostics and five-fault memory (retained through power loss) let a technician diagnose an issue before opening a single panel. 4Most Energy recommends annual refrigerant charge and defrost cycle verification, condenser and evaporator coil cleaning, filter replacement (1 in. standard, 2 in. pleated MERV 8 optional), and periodic RDS sensor verification on units equipped with the refrigerant detection option. 4Most Energy offers scheduled maintenance plans covering filter changes, coil cleaning, refrigerant circuit checks, and control board diagnostics.
Service Area
Greater Toronto Area (GTA) and surrounding regions
Toronto, Markham, Richmond Hill, Vaughan, Aurora, Newmarket, Scarborough, Brampton, and Mississauga.
Extended Service Area: Stouffville, Oshawa, Barrie, Orangeville, Hamilton, St. Catharines, Guelph, Kitchener.
Frequently Asked Questions
How is the Sunline WN Series different from the gas-heat Sunline KE Series?
The WN Series uses a heat pump as the primary heat source with optional field-installed electric heat as backup, while the Sunline KE Series pairs cooling with single-stage gas heat. Both share R-454B refrigerant, Smart Equipment™ controls, and the same cabinet/curb footprint, making the WN Series the electrification-focused option within the same platform.
How cold can it get before the heat pump needs electric backup?
The Sunline WN is rated at 3.00–3.35 COP at 47°F and 2.05–2.2 COP at 17°F. Below that range, or when the design heating load exceeds the heat pump's output, field-installed electric heat (5 to 30 kW) engages automatically to maintain space temperature.
Is R-454B refrigerant safe to use in an occupied building?
Yes. R-454B is a mildly flammable (A2L) refrigerant with a lower GWP than legacy R-410A. It must be installed and serviced by a licensed refrigeration mechanic, which 4Most Energy provides on every job, and an optional refrigerant detection system (RDS) is available for buildings that want automated leak sensing. For an R-410A option on the same platform, see the York Sunline XN Series.
Can I upgrade tonnage later without replacing the roof curb?
In many cases, yes — all three Sunline WN sizes share the same cabinet footprint and roof curb, so a future capacity change may not require new curb work. 4Most Energy always verifies electrical capacity for the new size before quoting.
Do you need a crane to install the Sunline WN?
It depends on roof height and access. The unit's full-perimeter base rails, three-side forklift slots, and rigging holes allow either forklift or overhead crane placement — we confirm the rigging method during the site assessment and include it in your quote.
What maintenance does the Sunline WN need?
We recommend annual refrigerant charge and defrost cycle verification, condenser and evaporator coil cleaning, filter replacement, and periodic RDS sensor checks on units with the refrigerant detection option. Tool-less access panels and the Smart Equipment™ board's fault memory keep service visits quick.
Does the Sunline WN Series qualify for Ontario electrification incentives?
Eligibility depends on each program's current efficiency thresholds, so 4Most Energy confirms it against the specific program when quoting. Most residential programs do not apply to commercial rooftop equipment.
