THERMO 2000 ComboMax Ultra 70 Electric Boiler with Integrated Hot Water | 9 kW - 240V
Thermo 2000’s 9 kW ComboMax Ultra 70 heats the home and makes hot water on demand, without ever storing it.
Model numberCOMBOU70-9
514 316-2973 · sales@airgreen.ca
Quick facts
Hot water made the moment you open the tap, and 9 kW to heat the home
No hot water waiting in a tank
A conventional water heater keeps dozens of gallons of hot water ready at all times. Thermo 2000’s ComboMax Ultra works differently. Its 71 US gal tank holds only the heating water, which circulates in a closed loop to your radiators or radiant floor. Drinking water, for its part, flows through parallel copper coils immersed in that hot water and heats up on the way. Nothing is stored: according to the manufacturer, this design reduces the risk of Legionella, and water arrives hot in under 7 seconds.
At the outlet, a pre-mounted thermostatic mixing valve tempers the water sent to the taps. A check valve meeting ASSE 1012 / CSA B64-3 and a 125 psi hot water relief valve are among the parts supplied.
Enough hot water for a busy family
The 9 kW 70 model, the COMBOU70-9, is designed for homes that draw a lot of hot water in a short time: morning showers, the children’s bath, the dishwasher. Thermo 2000 publishes 78 US gal in 10 minutes and 122 US gal in one hour, for water delivered at 110 °F, cold water at 40 °F and boiler water at 180 °F. The T2 UltraSmart controller gives priority to domestic hot water when it is drawn, then returns to heating.
Heating and electrical side
Two 4.5 kW elements, split over two stages, deliver 30,708 BTU/h at 240 V. The controller runs the heating pump when the thermostat calls. This size suits a two-storey or semi-detached home heated with hot water, in Montreal as in Laval, once the heating load is confirmed.
A 240 V single-phase circuit with a 50 A breaker and Cu 8 or Al 6 wire is required. At 208 V, output is multiplied by 0.75 and current by 0.867, according to the manufacturer. The unit is 70 1/2 in high and 24 in in diameter and weighs 430 lb empty; its connections are 1 1/4 in male NPT for heating and 3/4 in female NPT for domestic water.
What AirGreen’s installation covers
We first meet you for a free estimate, in Longueuil, on the South Shore, the North Shore or in Montreal. We assess your hot water and heating needs, the electrical panel and the planned location, then give you a detailed written quote.
On installation, the unit is set in place and connected, by qualified personnel, to the heating loop and the water supply. The supplied parts are installed, the electrical connection is made, then the loop is filled and purged. We set the controller, check water temperature at the taps and show you the backlit display and its settings.
AirGreen is a family business established in Montreal for more than fifteen years, holding RBQ licence 5645-9605-01 (ventilation, refrigeration and electrical). Thermo 2000 covers the tank and coils for 15 years in residential use (10 years in commercial use) and electrical and mechanical components for 2 years.
Ask for your free estimate: written quote and financing available for your 9 kW ComboMax Ultra 70.
Hot water made as it flows, not kept
In the COMBOU70-9, drinking water flows through copper coils immersed in 71 US gal of heating water and comes out hot. The same tank, heated by two 4.5 kW elements, feeds the home’s heating loop.
- Families who want hot water without stored reserves
- Two-storey homes heated by radiators, hot-water baseboards or radiant floors
- Households that use a lot of hot water in a short time
- Replacing a boiler and a water heater at the same time
Specifications
From the manufacturer’s documentation. A value the manufacturer does not publish is not listed.
What to know before installing
- The unit is 70 1/2 in high and 24 in in diameter and weighs 430 lb empty.
- 240 V single-phase circuit: 50 A breaker and Cu 8 / Al 6 wire, according to Thermo 2000.
- At 208 V, output is multiplied by 0.75 and current by 0.867, according to the manufacturer.
- 1 1/4 in male NPT connections (heating) and 3/4 in female NPT connections (domestic water).
- 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 hot water stored in the tank?
No. The tank holds the heating water, which circulates in a closed loop. Drinking water flows through copper coils immersed in that water and heats up on the way; no domestic hot water is stored.
How much hot water do you get?
Thermo 2000 publishes 78 US gal in 10 minutes and 122 US gal in one hour for the COMBOU70-9, with water delivered at 110 °F, cold water at 40 °F and boiler water at 180 °F.
Do I need to buy a mixing valve or a check valve separately?
No. The thermostatic mixing valve, the 12 psi pressure regulator and the check valve (ASSE 1012 / CSA B64-3) are among the parts supplied by Thermo 2000.
What changes on a 208 V supply?
According to the manufacturer, output is multiplied by 0.75 and current by 0.867. We take that into account when choosing the size if your building runs on 208 V.
Can it go in a closet?
Only if the space offers the necessary height and diameter (70 1/2 in and 24 in), a floor that carries the filled unit, and the service access required by the manufacturer. We check it on site.
A 9 kW ComboMax Ultra 70, 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.