GENERAL AIRSTAGE CENTAURI XLTH R32 Electric Furnace | 4 Tons - 48000 BTU

GENERAL AIRSTAGE CENTAURI XLTH 48,000 BTU electric furnace: one duct system for the duplex or the large house

In a duplex lived in by one family, a single basement electric furnace sometimes feeds both floors through a shared duct system; the same goes for the large single-family home. To replace it, this 4-ton GENERAL AIRSTAGE CENTAURI XLTH system, that is 48,000 BTU, brings together two units: the AMUH48KUAS, a multi-position air handler set in place of the furnace, and the AOUH48KUAH1, an outdoor Heat Pump that heats down to −26 °C according to the manufacturer. The electric backup heat kit, mounted in the indoor unit, provides reinforcement.

Under the Fujitsu AIRSTAGE CENTAURI XLTH name, the same pair of units carries exactly the same numbers. The manufacturer traded the Fujitsu General Limited name for GENERAL Inc. on January 1, 2026, without touching the spec sheet or the warranty.

One point to settle from the start: one duct system means one control and one temperature setpoint for everything the system serves. If each dwelling needs to set its own temperature, two separate systems are the better answer, and we will tell you so. When the household lives on the same schedule, on the other hand, a well-tuned 4-ton system does the job, and that tuning depends largely on commissioning.

GENERAL or Fujitsu AIRSTAGE: the same machine

It all starts with an acquisition: in August 2025, Paloma Rheem Holdings, Rheem's owner since 1988, bought Fujitsu General Limited. The AIRSTAGE products carried over as they were, with their model numbers, their factories and their warranty program, and Groupe Master remains the distributor that supplies them to us.

The Fujitsu name will disappear from the cabinets as the transition proceeds. Until then, we present each system under both of its names, on two pages that the table below compares point by point.

The version bearing the former name is still available: Fujitsu AIRSTAGE CENTAURI XLTH 4-ton electric furnace.

In the basement, the unit that succeeds the furnace measures 21 × 21 × 48 in. (W × D × H); once the ducts have been inspected, it is tied to the supply plenum and the return air. Thanks to its multi-position design, the AMUH48KUAS installs standing, upflow or downflow with the UTD-DFMMB1 kit, just as well as lying down toward the left or the right. The grilles on both floors stay where they are.

For a duct system serving two levels, everything starts with airflow. On the air side, the unit reaches 1,600 CFM at most, and the manufacturer sets its external static pressure range at 0.2 to 0.8 in. WC. In a duplex, the ducts running up to the upper dwelling are the longest, and the upstairs return air often decides comfort. We look at them during the visit, which is also when the final layout and grille count get fixed.

In deep cold, the AOUH48KUAH1 keeps heating down to −26 °C; its cooling range, for its part, runs from −21 °C to 50 °C. According to the certified file, it delivers 34,000 BTU, with a COP of 2.86, at −8 °C, and 51,000 BTU, with a COP of 1.96, at −15 °C: two distinct test conditions, each to be read on its own. Its seasonal ratings, recorded on AHRI certificate 217895718: SEER2 of 19.0, HSPF2 of 10.2, EER2 of 11.2. ENERGY STAR cold climate certification is granted to it under ID 4511774.

Commissioning is the stage where a system this size is won or lost. The refrigeration technician who starts up the installation takes care of the following, among other things:

• testing the refrigerant line for leaks (3/8 and 5/8 in. tubes), then pulling a vacuum before releasing the R-32 refrigerant;
• checking the charge according to the manufacturer's instructions;
• measuring the duct system's static pressure and comparing it with the manufacturer's range;
• choosing and programming the backup heat logic, then running the kit to validate it;
• connecting and testing the input/output terminals in use, for example for an HRV, a humidifier or a fire alarm;
• confirming that the selected control works.

Backup tuning deserves a closer look. A 4-ton system heating two floors needs serious reinforcement on the coldest nights, and below −26 °C, the kit takes over. The air handler offers several backup logics: the technician picks the one that lets the heat pump lead the heating and brings the elements in only when the house needs them. The manufacturer's compatible kit, sold separately, requires its own circuit; the system, for its part, needs a 208/230 V supply (MCA 29 A, MOP 40 A). In a duplex, we also locate which electrical panel feeds the old furnace.

The 37.01 × 12.60 × 54.33 in. outdoor unit is tall and shallow, and its spec sheet shows 60 dB(A). In a duplex yard, it goes on a pad or a bracket, well clear of both dwellings' bedroom windows and balconies. The route of the refrigerant line, cable and drain is decided on site, based on how the yard is laid out.

No control comes with the system. The KAGAMI UTY-RVRU or UTY-RNRUZ5 wired wall controller goes in the dwelling whose temperature should serve as the reference; a 24 V thermostat compatible with a heat pump and its backup can also be kept through the UTY-TTRXZ1 interface. As options, there remain Wi-Fi with the AIRSTAGE Mobile app and the wireless remote fitted with its IR receiver kit; as for service monitoring, it goes through a compatible controller.

Indoors, the air handler runs from 34 dB(A) at its lowest to 51 dB(A) at its highest. In summer, it cools both floors through the same ducts and removes 4.7 pints/h of moisture, according to the spec sheet. A leak detection system is factory-integrated.

The filter is changed through a panel built for maintenance; as an option, it sits on a 20 × 20 in. base. In a duplex, it is best to decide at installation who looks after the filter: with 1,600 CFM to pass, it clogs quickly if forgotten.

Hydro-Québec set aside $4,080 for it in the October 27, 2026 version of its LogisVert list; the list on the day you apply is still the one that applies. The manufacturer's warranty extends to 12 years for the compressor and parts, and 6 years for labour. AirGreen sells this same system as a "central heat pump" too.

In short, this size targets the duplex occupied by one family or the large house served by a single duct system in good condition. The heat-loss calculation, done at your home, confirms the 4 tons or not, and AirGreen, an HVAC contractor and AIRSTAGE Elite Plus installer, will tell you frankly if two systems would suit you better.

Official brochures

The manufacturer's brochures are available as PDF files:

• Brochure in French (PDF)
• Brochure in English (PDF)

Renaud and all of Laval: a free quote for your duplex or large house

Our team travels to Renaud as well as the rest of Laval, and also covers Montreal, Longueuil, the North Shore and the South Shore. Reach us at 514 316-2973: the quote is free, and the visit covers the furnace, the ducts on both floors, the electrical panel and the yard.

When you call, let us know whether both floors are lived in by the same family. The answer already points the choice between one system and two.