THERMO 2000 BuffMax BUFF120-3NPT-HRZ-HC Buffer Tank (119 US gallons)

The largest BuffMax for heating water and chilled water

The Thermo 2000 BuffMax BUFF120-3NPT-HRZ-HC buffer tank tops the HC series. It is meant for water loops that serve an entire building: several units, offices, a store. Like its smaller siblings, it combines three functions in one insulated vessel: buffer tank, storage tank and hydraulic separator. What sets it apart are its four 3 in NPT connections and its large volume.

119 US gallons: what the name does not say

The name BUFF120 suggests 120 gallons. Thermo 2000 nevertheless states 119 US gallons for this non-ASME model, and that is the figure we use to size your loop. The difference matters little in a building, but we prefer to give you the manufacturer’s exact value.

For buildings where heating and cooling run on water

Picture a six-unit building in Montreal heated by a central electric boiler, or a small commercial building in Laval where fan coils heat in winter and cool in summer thanks to a reversible air-to-water heat pump. In both cases, demand changes constantly with the tenants, the schedules and the weather. The BUFF120 keeps a stable reserve, lets the source run longer cycles and separates its circuit from the distribution circuit. The HC code confirms that it accepts heating water and chilled water, and Thermo 2000 recommends it for low-mass boilers, heat pump systems and multi-zone systems.

The 2-inch HFC-free polyurethane insulation limits heat loss to 1/2 °F per hour, according to the manufacturer. The tank accepts a maximum working pressure of 150 psi and a maximum temperature of 121 °C (250 °F). It works in a closed loop only: no connection to domestic hot water or to an atmospheric system.

One point to check early: this model is not built to the ASME code. If your engineer or the building plans require it, the BuffMax series also includes ASME models, for heating water only.

Planning space for a 79-inch tank

The BUFF120 is 79 inches high and 28 inches in diameter. It needs a proper mechanical room, with room on each side for the 3 in piping and access to the 3/4 in drain valve. We check the clear height, the door widths and the delivery path before ordering, especially in older buildings in Longueuil, on the South Shore or on the North Shore.

How we work

We start with a free on-site visit and estimate, followed by a written quote. At installation, we set and level the tank on its adjustable legs, connect the source and the distribution, install the supplied automatic air vent, ball valve, temperature and pressure indicator and immersion well, then fill, purge and commission the loop. AirGreen is a family business established in Montreal for more than 15 years, holding RBQ licence 5645-9605-01 (ventilation, refrigeration and electrical). Thermo 2000 warrants the tank for 5 years and the mechanical parts for 2 years, under its terms.

Tell us about your building, its heat source and its zones: we confirm whether the BUFF120 or an ASME model is the right fit. Free estimate and financing available.