Carrier WeatherMaster 48GE Light Commercial Gas Heat/Electric Cooling Rooftop Unit – Supplied & Professionally Installed by 4Most Energy
The WeatherMaster 48GE is a single-package gas heating/electric cooling rooftop unit built for small commercial buildings in the 3 to 5 nominal ton range. A two-stage scroll compressor circuit on next-generation Puron Advance (R-454B) refrigerant delivers up to 16.8 SEER2 and 12.0 EER2 (17.2 SEER/12.5 EER under DOE 2018 Appendix M ratings), while the patented EcoBlueTM vane axial indoor fan system — direct-drive, electronically commutated, with 75% fewer moving parts than a belt-drive forward-curved fan — cuts fan energy and eliminates belt, pulley, and bearing maintenance. Two-stage induced-draft gas heat is available in low, medium, and high input configurations from 50/40 MBH up to 150/120 MBH input/output per stage, with aluminized or optional stainless steel heat exchangers, direct-spark ignition, and 81–82% thermal/AFUE efficiency; a Ultra Low NOx (14 ng/J) heat exchanger option is also available where local emissions requirements apply. R-454B carries a global warming potential of 466 — a 75% reduction versus legacy R-410A — and, as an A2L mildly flammable refrigerant, the unit ships with a factory-installed, UL 60335-2-40–certified leak detection and dissipation system designed to operate for the life of the unit. All 48GE units meet ASHRAE 90.1 and DOE minimum efficiency standards, comply with the US Energy Policy Act (2005), and are AHRI 210/240 certified and UL listed.
Rated performance depends entirely on correct field installation. Ontario gas heat installations require licensed TSSA gas technician sizing of the gas line and meter to the unit's natural gas supply pressure (4–13 in. wg) or a propane conversion kit, combustion and gas-train testing at start-up, and induced-draft venting configured per the unit's vertical or field-convertible horizontal discharge orientation. Roof curb selection (14 in. or 24 in.), structural load review, thru-the-base gas and electrical connections, ESA-compliant electrical hookup sized to the unit's voltage (208/230-1/3-60, 460-3-60, or 575-3-60) and MCA/MOCP rating, and correct commissioning of the A2L refrigerant leak dissipation system are equally code-driven and equally easy to get wrong without an experienced crew. 4Most Energy is a certified installer for rooftop unit installation Toronto, packaged RTU replacement GTA, and Carrier WeatherMaster 48GE installation Ontario projects, providing licensed gas technician near me–level combustion testing and commissioning and ENERGY STAR–calibre rooftop unit Toronto service standards on every job — so the SEER2 and thermal efficiency figures on the nameplate are what the building actually gets, not just what's on the spec sheet.
Replacement Option
The WeatherMaster 48GE is engineered to fit existing 3-to-5-ton roof curbs, and — using an appropriately sized curb adapter to bridge differing roof curb and duct footprints — it can also replace aging Trane, Lennox, York (Johnson Controls), Daikin, Rheem, and AAON gas/electric packaged rooftop units of comparable tonnage. This lets 4Most Energy replace an aging light-commercial rooftop unit from any of these manufacturers without necessarily requiring a full roof curb and structural rework, minimizing both project cost and rooftop downtime.
Warranty
Carrier backs the WeatherMaster 48GE with a 3-year limited parts warranty from the factory. 4Most Energy handles warranty registration and start-up documentation on your behalf.
Documents
Why Install the Carrier WeatherMaster 48QE with 4Most Energy?
- EcoBlue vane axial indoor fan system direct-drive ECM motor, 75% fewer moving parts, slow ramp-up, and phase loss protection for quieter, more reliable operation than belt-drive forward-curved fans.
- Puron Advance (R-454B) refrigerant 466 GWP, a 75% reduction versus legacy R-410A, easily meeting the EPA's <700 GWP requirement, paired with a factory-installed, UL 60335-2-40–certified leak dissipation control board and sensor designed to last the life of the unit.
- Two-stage cooling with scroll compressor TXV metering, fully active evaporator coil, internal line-break overload protection, and no-strip screw collars throughout for faster field service.
- Two-stage induced-draft gas heat low, medium, or high input configurations with direct-spark ignition and dimpled heat exchanger tubes for improved heat transfer; standard aluminized or optional stainless steel heat exchanger for high-humidity or corrosive environments, plus an Ultra Low NOx (14 ng/J) option.
- Up to 16.8 SEER2 / 12.0 EER2 two-stage cooling capacity control on Standard/Medium or High Static EcoBlueTM vane axial fan configurations.
- Optional Humidi-MiZer adaptive dehumidification system improved part-load humidity performance on N-series models.
- Optional SystemVu intelligent DDC controller large backlit display, quick-status LEDs, USB data port, and built-in i-Vu, CCN, and BACnet compatibility for building automation integration, plus EconomizerONE fault detection and diagnostics.
- Re-designed unit control board (UCB) with dial-and-switch indoor fan adjustment, large terminal connections, and clearly labeled plug-in connection points to reduce installation time.
- Tool-less filter access door, handled access panels, and a sloped, corrosion-resistant composite drain pan that sheds water and will not rust.
- Field-convertible horizontal airflow on all 3-to-5-ton models, simplifying replacement on existing curbs.
Model 48GE Specifications
| Model | Nominal Tons |
Net Cooling (MBH) |
SEER2 | EER2 | SEER (Appendix M) |
EER (Appendix M) |
Rated CFM Range |
Sound (dBA, A-wtd) |
Base Unit Weight (lb) |
|---|---|---|---|---|---|---|---|---|---|
| 48GE*04 | 3.0 | 36.0 | 16.8 | 12.0 | 17.2 | 12.5 | 900–1,500 | 75.4 | 535 |
| 48GE*05 | 4.0 | 48.0 | 16.8 | 12.0 | 17.2 | 12.5 | 1,200–2,000 | 79.0 | 555 |
| 48GE*06 | 5.0 | 58.5 | 16.8 | 12.0 | 17.2 | 12.5 | 1,500–2,500 | 79.0 | 600 |
Ratings per AHRI Standard 210/240 at 80°F/67°F wb indoor, 95°F db outdoor. SEER2/EER2 reflect DOE 2023 (M1) test procedure; SEER/EER reflect
DOE 2018 Appendix M ratings (208/230-3-60, 460-3-60, and 575-3-60 voltage codes only).
| Gas Heat Option (per stage, Input/Output MBH, 3-phase) |
04 | 05 | 06 |
|---|---|---|---|
| Low | 50/40 – 67/54 | 50/40 – 67/54 | 50/40 – 67/54 |
| Medium | 82/65 – 110/88 | 82/65 – 110/88 | 82/65 – 110/88 |
| High | — | 120/96 – 150/120 | 120/96 – 150/120 |
Thermal/AFUE efficiency 80–82% across all gas heat configurations (single- and three-phase). Natural gas and propane input/output identical;
propane requires a field-installed conversion kit and is not available on Ultra Low NOx units. Ultra Low NOx (14 ng/J) heat exchanger option
available in stainless steel, low or medium heat, on 0–7,800 ft elevation installations only.
The 48GE is sized first by cooling load (3–5 nominal tons) using a proper Manual N/commercial load calculation — not by matching the tonnage of the unit being replaced, since older rooftop units on the same curb were frequently oversized by the standards of their era. Gas heat input (low/medium/high, by stage) should be selected against the building's actual heat loss calculation and the temperature rise range specified for the unit and airflow setting, not defaulted to the highest available input. Buildings near sound-sensitive property lines or with rooftop-adjacent occupied space should weigh the 75.4–79.0 dBA outdoor sound ratings into curb placement and unit selection, particularly on the 4- and 5-ton sizes. 4Most Energy performs load calculation, gas capacity verification, and roof structural review as part of every quote before ordering.
Installation & Assessment Checklist
| Phase | Description & Key Requirements | |
|---|---|---|
| Step 1 | Site Assessment | Existing unit and curb inspection, gas service and meter capacity check, electrical service review, and roof structural/access evaluation. |
| Step 2 | Load Calculation & Unit Sizing | Confirm correct tonnage, gas heat input level, airflow configuration (vertical or horizontal), and control option (standard thermostat or SystemVu™). |
| Step 3 | Rigging & Crane Setup | WeatherMaster's lightweight base-rail design simplifies crane placement onto the existing or new roof curb for these 3-to-5-ton units. |
| Step 4 | Roof Curb & Structural Prep | Install or verify 14 in./24 in. roof curb, full-perimeter seal, and structural support for the unit's operating weight. |
| Step 5 | Gas Line & Venting Connection | Licensed TSSA gas technician sizes and connects the gas line (thru-the-base connection), verifies supply pressure, and configures induced-draft venting for the unit's discharge orientation. |
| Step 6 | Electrical Connection | ESA-compliant hookup to the building's disconnect, sized to the unit's voltage, phase, and MCA/MOCP rating, with thru-the-base electrical connections as specified. |
| Step 7 | Ductwork Tie-in | Supply and return duct connection matched to vertical or horizontal discharge, with sealed transitions. |
| Step 8 | Commissioning | Combustion analysis and gas train test, refrigerant charge verification, A2L leak dissipation system function test, airflow and temperature rise confirmation, and control system setup (thermostat or SystemVu™/BAS integration), with warranty registration filed. |
| Step 9 | Final Walkthrough | Filter access, service clearances, and control operation demonstrated before the crew leaves site. |
Carrier's standard coverage on the WeatherMaster 48GE is a 3-year limited parts warranty from the factory. 4Most Energy completes and files the required start-up and combustion test documentation to keep warranty coverage valid.
Routine maintenance is straightforward by design: the EcoBlue direct-drive fan requires no belts, pulleys, or shaft bearings to inspect or replace, and the tool-less filter door simplifies the most frequent service task. Carrier recommends annual combustion testing and gas train inspection on all gas heat units, condenser coil cleaning, condensate drain pan/trap inspection, and a functional test of the A2L refrigerant leak dissipation system's "Test" button and status LED. 4Most Energy offers scheduled maintenance plans covering filter changes, combustion analysis, refrigerant circuit and leak-sensor checks, and control board diagnostics via the unit's built-in LED status indicators.
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
What is R-454B, and does the refrigerant change affect installation?
R-454B (Puron Advance) is Carrier's next-generation refrigerant with a GWP of 466 — 75% lower than R-410A — classified as "mildly flammable" (A2L) by ASHRAE. The 48GE ships with a factory-installed leak detection and dissipation system certified to UL 60335-2-40 that requires no field configuration, but 4Most Energy's technicians follow A2L-specific handling, charging, and commissioning procedures during installation.
Can the 48GE run on propane instead of natural gas?
Yes — a field-installed propane conversion kit is available for standard 48GE sizes, using the same input/output ratings as the natural gas configuration at elevations up to 2,000 ft; propane is not available on Ultra Low NOx units.
Is the 48GE a direct replacement for our existing rooftop unit?
In most cases the unit is designed to fit on existing 3-to-5-ton curbs without modification, though 4Most Energy always verifies curb dimensions, gas/electrical connection points, and structural load before ordering.
How loud is the 48GE, and will it be a problem for occupied space below the roof?
A-weighted outdoor sound is 75.4 dBA on the 3-ton size and 79.0 dBA on the 4- and 5-ton sizes. For sound-sensitive locations, 4Most Energy can advise on curb placement, sizing alternatives, or accessory sound treatment during the quote.
Does the 48GE support building automation system integration?
Yes — the optional SystemVu controller provides built-in i-Vu, BACnet, and Carrier Comfort Network (CCN) capability, or the unit can operate on a conventional thermostat with standalone controls.
