THERMO 2000 BuffMax BUFF120A-3NPT-HRZ-HT ASME Buffer Tank (120 gallons)
Thermo 2000 BuffMax 120 US gallon buffer tank built to the ASME code, Section VIII, Division 1, for closed heating-water loops.
Model numberBUFF120A-3NPT-HRZ-HT
514 316-2973 · sales@airgreen.ca
Quick facts
An ASME buffer tank for heating loops that require it
In a commercial or rental project, the mechanical specification often states how each pressure vessel must be built. The Thermo 2000 BuffMax BUFF120A-3NPT-HRZ-HT buffer tank meets this requirement: its 120 US gallons are held in a vessel built to Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code. It keeps the series’ 3-in-1 principle: buffer tank, storage tank and hydraulic separator.
Why choose the ASME version
If your building plans or engineer require an ASME tank, this model and its larger 175 and 200-gallon siblings are the BuffMax tanks to consider. Thermo 2000 gives it a maximum working pressure of 125 psi. Its four 3 in NPT side connections, two on each side, separate the source circuit from the distribution circuit, and three 1/2 in connections plus an immersion well take the temperature sensor.
The source can be an electric boiler serving a building in Montreal, or an air-to-water heat pump heating several zones of a commercial building in Laval. In both cases, the tank lets the source run longer cycles while the zones draw the water they need. Thermo 2000 recommends the BuffMax for low-mass boilers, heat pump systems and multi-zone systems.
What the HT code means for your project
The HT suffix indicates a tank intended for heating water. If your loop must also carry chilled water for cooling, you need an HC version of the BuffMax, which is not built to the ASME code. We sort this out with you from the estimate stage. Another point from the manufacturer: the BXT option, which adds connections at the centre of the tank, is not available on ASME models. Finally, like every BuffMax, this tank works in a closed loop and is never connected to domestic hot water or to an atmospheric system.
Handling and location
The tank is 78 1/4 inches high and 28 inches in diameter. It has lifting lugs for handling and stands on adjustable legs. The 2-inch HFC-free polyurethane insulation limits heat loss to 1/2 °F per hour, according to the manufacturer. The tank comes with a 1/2 in ball valve and automatic air vent, a 2 1/2 in temperature and pressure indicator, an immersion well and a 3/4 in drain valve.
Our installation
We install the BUFF120A in Montreal, Longueuil, on the South Shore, on the North Shore and throughout Greater Montreal, with electric boilers and air-to-water heat pumps. The on-site estimate is free and the quote is written. On installation day, we place the tank, connect it on the source side and the distribution side, install the supplied accessories, 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 in heating applications and the mechanical parts for 2 years, under its terms.
Send us the mechanical specification or the plans for your project: we confirm the ASME size that fits. Free estimate and financing available.
The buffer tank for projects that require ASME
The BUFF120A uses the BuffMax 3-in-1 principle, buffer tank, storage tank and hydraulic separator, in a vessel built to the ASME code. It is meant for buildings whose plans or engineer require this construction for the heating-water loop.
- Rental or commercial building whose specifications require an ASME tank
- Heating-water loop supplied by an electric boiler
- Air-to-water heat pump system serving several heating zones
- Replacing an existing ASME buffer tank of a comparable size
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- Heating water only (HT code): a chilled-water loop needs an HC version of the BuffMax.
- Maximum working pressure of 125 psi (ASME): the loop pressure must stay below this limit.
- The BXT option (centre connections) is not available on ASME models.
- 78 1/4 in high and 28 in in diameter: plan access and handling with the lifting lugs.
- Closed loop only: Thermo 2000 prohibits connection to domestic hot water or to an atmospheric system.
- 1/2 in ball valve
- 1/2 in automatic air vent
- 2 1/2 in temperature and pressure indicator
- Immersion well
- 3/4 in drain valve
- Adjustable legs
- Lifting lugs
Manufacturer documents
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Frequently asked questions
What does ASME construction mean for this tank?
Thermo 2000 builds the BUFF120A to Section VIII, Division 1, of the ASME Boiler and Pressure Vessel Code, with a maximum working pressure of 125 psi. It is the version to choose when the building plans or engineer require an ASME tank.
Can it be used for a chilled-water loop?
No. The HT code means heating water. For a loop that also carries chilled water, the BuffMax series offers HC models, which are not built to the ASME code.
How is the tank handled?
The tank is 78 1/4 in high and 28 in in diameter and has lifting lugs. We plan the delivery path and the handling to the mechanical room before installation day.
Can centre connections be added?
No. Thermo 2000 states that the BXT option, which adds 2 centre connections, is not available on ASME models.
What warranty does Thermo 2000 offer?
The tank is warranted for 5 years in heating applications and the mechanical parts for 2 years, in residential or commercial use in Canada and the United States. Removal, reinstallation and shipping are paid by the owner, under the manufacturer’s terms.
A 120-gallon ASME BuffMax, installed by AirGreen
Tell us about your project: we check the sizing, confirm availability and send you a quote. Or let our technicians install it for you.
Specifications from the manufacturer’s documentation, checked on October 19, 2026.