THERMO 2000 ComboMax Ultra 70 Electric Boiler with Integrated Hot Water | 12 kW - 240V
For larger homes: Thermo 2000’s 12 kW ComboMax Ultra 70 heats the hot-water loop and delivers 139 US gal of hot water in one hour.
Model numberCOMBOU70-12
514 316-2973 · sales@airgreen.ca
Quick facts
139 US gal of hot water in one hour and 12 kW of heating, for larger homes
For homes where hot water must not run out
Several bathrooms, a deep tub, a multi-jet shower: in a larger home, hot water is often the first weak spot. Thermo 2000’s 12 kW ComboMax Ultra 70 answers with its large 71 US gal tank. According to the manufacturer, it delivers 81 US gal of hot water in the first 10 minutes and 139 US gal in one hour, for water at 110 °F, cold water at 40 °F and boiler water at 180 °F.
Hot water is not stored. The tank holds the heating water; drinking water flows through parallel copper coils immersed in that water and heats up along the way. Thermo 2000 states that it arrives hot in under 7 seconds, and that this design reduces the risk of Legionella. A pre-mounted thermostatic mixing valve tempers the water sent to the taps.
Heating: two 6 kW elements
On the heating side, the COMBOU70-12 has two 6 kW elements on two stages, for 40,944 BTU/h at 240 V. It feeds a radiant floor, radiators or hot-water baseboards. The T2 UltraSmart controller gives priority to domestic hot water and runs the heating pump when the thermostat calls.
The unit draws 50 A at 240 V; Thermo 2000 specifies a 70 A breaker and Cu 6 or Al 4 wire. At 208 V, output is multiplied by 0.75 and current by 0.867. The large tank also needs room: 70 1/2 in high, 24 in in diameter and 430 lb empty, with 1 1/4 in male NPT heating connections.
A unit designed to last
Thermo 2000 announces an expected service life of more than 30 years and minimal maintenance. The manufacturer warranty follows: 15 years on the tank and coils in residential use, 10 years in commercial use and 2 years on electrical and mechanical components. In a larger home in Laval, on the North Shore or the South Shore, replacing two appliances with one also simplifies the mechanical room for years to come.
AirGreen’s installation
We start with a free on-site estimate, in Montreal, Longueuil and throughout Greater Montreal. We talk about your hot water use, measure the location, check the electrical panel and the heating loop. The written quote specifies the unit, the 70 A circuit, the loop components and the steps.
On installation, the unit is set in place and connected, by qualified personnel, to the heating loop and to domestic water. The pressure regulator with check valve, the automatic air vent and the temperature and pressure gauge arrive already mounted. We make the electrical connection, fill and purge the loop, set the controller and check water temperature at several taps.
AirGreen is a family business established in Montreal for more than fifteen years, holding RBQ licence 5645-9605-01 (ventilation, refrigeration and electrical).
Ask for your free estimate and written quote for the 12 kW ComboMax Ultra 70; financing is available.
Plenty of hot water and 12 kW of heating, in one appliance
The COMBOU70-12 combines two 6 kW elements with the series’ large 71 US gal tank. Drinking water is heated as it passes through copper coils immersed in the heating water.
- Larger homes with several bathrooms
- Deep tubs and multi-jet showers that call for a high flow of hot water
- Homes heated by radiant floors on more than one level
- Owners who want a single durable appliance to maintain
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- 240 V single-phase circuit: the unit draws 50 A; Thermo 2000 specifies a 70 A breaker and Cu 6 / Al 4 wire.
- 70 1/2 in high, 24 in in diameter, 430 lb empty: plan the access and a floor able to carry the filled unit.
- At 208 V, output is multiplied by 0.75 and current by 0.867, according to the manufacturer.
- 1 1/4 in male NPT heating connections; 3/4 in female NPT domestic water connections.
- 30 psi heating relief valve
- 125 psi domestic hot water relief valve
- Tank and heat exchanger drain valves
- Temperature and pressure gauge
- Automatic air vent
- 12 psi pressure regulator
- Check valve (ASSE 1012 / CSA B64-3)
- Thermostatic mixing valve
- Heating elements and T2 UltraSmart controller
Manufacturer documents
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Frequently asked questions
Is it enough for a home with several bathrooms?
Thermo 2000 publishes 81 US gal of hot water in 10 minutes and 139 US gal in one hour (water at 110 °F, cold water at 40 °F, boiler water at 180 °F). During the visit, we compare these values with the number of bathrooms and your habits before confirming the size.
What does the T2 UltraSmart controller do?
It manages domestic hot water temperature and gives it priority, runs the heating pump when the thermostat calls and shows the unit’s status on a backlit display.
How does it differ from the 12 kW ComboMax Ultra 50?
Heating output and electrical load are the same as the COMBOU50-12. The COMBOU70-12 has a larger tank that delivers more hot water, and larger heating connections; it is also taller and heavier.
How long does this kind of unit last?
Thermo 2000 announces an expected service life of more than 30 years and minimal maintenance. The manufacturer warranty covers the tank and coils for 15 years in residential use.
What electrical circuit is needed?
A 70 A, 240 V single-phase circuit with Cu 6 or Al 4 wire; the unit draws 50 A according to the manufacturer.
A 12 kW ComboMax Ultra 70 for a larger home, 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.