Packaged Heat Pump System Gree Rooftop R32 3 Ton | Montreal, Laval, Longueuil, South Shore and North Shore
Replacing an old rooftop unit or electric baseboards while keeping your ducts
In many commercial spaces and multiplexes in Montreal, Laval and Longueuil, the heating still rests on an old rooftop unit at the end of its life or on electric baseboards. The packaged heat pump Rooftop R32 from Gree in the 3 ton size (36,000 BTU/h rated capacity) lends itself well to that kind of retrofit: a single outdoor cabinet, all-electric, that brings together the compressor, the coils and the fan, connects to the building's duct system and delivers both heating and air conditioning.
Our approach at AirGreen is to make the most of what is already there, whether that is the ducts, the location of the old unit or even the thermostat, and to replace only what has to be replaced. We do this work everywhere in Montreal, Laval, Longueuil, on the North Shore and on the South Shore.
First case: the old rooftop unit is reaching the end of its life
An aging rooftop unit is quick to recognize: repairs one after another, unusual noise, uneven comfort from one end of the space to the other. When the building already has a duct system in good condition, replacing it with a packaged unit avoids opening up the ceilings and redoing the air distribution. The occupants find their grilles in the same place; only the unit changes.
During the visit, we compare the existing location with the dimensions of the new cabinet, that is 44 × 35-7/16 × 49-1/4 in. (1,120 × 900 × 1,250 mm), and with its net weight of 523 lb. We also look at the connection of the supply and return ducts, the condition of the insulation and the tightness of the joints. Since the unit is all-electric, no fuel connection has to be planned.
Another advantage for small buildings: the supply is 208-230 V, single-phase, 60 Hz. A building with no three-phase service, like many multiplexes and neighbourhood commercial spaces, therefore does not have to have one installed to take the unit.
Second case: moving off electric baseboards
Baseboards heat each room separately and provide no air conditioning. In a commercial space or a multiplex that already has a duct system, or where one can be built, the packaged heat pump replaces that room-by-room heating with central air distribution, with air conditioning as a bonus in summer.
In heating, the 3 ton certifies a COP of 1.90 at -15 °C, which means it delivers 1.90 units of heat for every unit of electricity it draws, and that at maximum compressor speed. A baseboard, for its part, simply turns electricity into heat. ENERGY STAR Cold Climate certified, the unit delivers heating down to -30 °C outdoors and runs in that mode up to 24 °C. Depending on how the space is laid out, some baseboards can stay in place in rooms the ducts do not serve; we discuss that with you during the estimate.
Commercial space or multiplex: what changes day to day
- Commercial space: a single control for the sales floor or the offices instead of a series of baseboard thermostats, and an air-conditioned space for your customers and your employees in summer.
- Multiplex: a dwelling or a floor served by a single duct system, heated and cooled by equipment installed outside, so with no indoor unit to house in the rooms.
- Mixed-use building: a commercial ground floor renovated while the upper floors keep their current system, one step at a time.
Keeping your 24 V thermostat or moving to the GREE controller
In a retrofit, the control often calls for compromises: new wires to run through finished walls, tenants used to their thermostat. The universal control connection on the Rooftop R32 leaves two options.
- The GREE controller included: it links to the unit by two-wire communication. Since that communication is polarity-free, the order of the two wires does not matter, which limits wiring mistakes.
- The standard 24 V connection: a 24 V thermostat already in place can be wired to the unit if it is compatible, which suits the manager or the tenant who prefers to keep the control they know.
The communication distance can reach 30 m (98.5 ft.) between the unit and the control. That leaves some room to place the thermostat in the right spot in the space, away from entrance doors and heat sources. Central control is provided for, and remote control is possible with an optional gateway.
What the retrofit calls for, from the roof to the electrical panel
A successful replacement is prepared in advance. Here are the points we go over before giving you a recommendation.
The existing ducts
The 3 ton moves 1,120, 800 or 700 CFM depending on the speed (high, medium or low), with an external static pressure of 0.50 in. within a range of 0 to 0.7 in. Ducts sized for an older unit may call for adjustments: grilles to add, a return air opening to enlarge, sections to seal. We measure before proposing anything.
The electrical supply
We check that the panel can take a 208-230 V single-phase circuit and we coordinate the connection with your electrician when work is required.
The location and the noise
The published sound pressure is 63 dB(A). In a multiplex, we take into account the windows of the dwellings and the neighbours; on a commercial roof, the access for maintenance.
Commissioning
We program the control, check the air distribution at the grilles and explain how it works to the owner or the tenant.
The certified data for the 3 ton
- Rated capacity: 36,000 BTU/h.
- Certified cooling at 35 °C: 34,000 BTU/h.
- Certified heating at 8.3 °C: 34,000 BTU/h.
- Heating at -8.3 °C (17 °F): 21,800 BTU/h, the certified rated capacity.
- Heating at -15 °C (5 °F): 29,000 BTU/h, measured at maximum compressor speed.
- SEER2 of 18.0, EER2 of 11.2, HSPF2 of 8.5 (region IV) and COP of 1.90 at -15 °C.
- AHRI no. 215866830 and ENERGY STAR certificate no. 3721888.
The figure at -15 °C is higher than the one at -8.3 °C because they do not measure the same thing. The first is obtained at maximum compressor speed, as the ENERGY STAR Cold Climate criterion requires; the second is the certified rated capacity. We take both into account to size the installation.
Gree construction and technologies
Gree's "Ultra-Heat" technology combines two-stage, twin-cylinder compression with hot gas injection, for heating performance in cold weather. To that are added high-efficiency DC Inverter technology, anti-corrosion and dust-resistant construction, multiple protections, multi-parameter regulation, zero-wind start-up and an emergency operating mode. The refrigerant is R-32 (charge of 149.9 oz). In cooling, the unit runs from -5 °C to 52 °C outdoors. If your building calls for another size, our packaged heat pumps page presents the other capacities and brands we install.
Let us plan the replacement of your system
Old rooftop unit or electric baseboards, we assess your ducts, your power supply and your current control, then we propose a packaged heat pump installation suited to your building. 100% free on-site estimate anywhere in Montreal, Laval, Longueuil, the North Shore and the South Shore. Call AirGreen at 514 316-2973. AirGreen inc., RBQ licence 5645-9605-01.