UltraGas® 2 D (250 - 3100)
Heating flow

with additional system flow sensor (optional) for improved plant efficiency.

Separate high and low temperature returns

provide ideal conditions for condensation and therefore increase energy recovery from the flue gases.

Future-proof Ultraclean® burner technology - also suitable for regenerative gases such as biomethane

the modulating gas burner matches the output exactly to the requirement, reduces the switching frequency and guarantees clean, low-emission and energy-saving combustion.

TurboFer® heat exchanger

this patented Hoval innovation in vertical arrangement and the large water content for maximum heat transfer and more cost effectiveness.

Systemic regulation TopTronic® E

makes ecological, economical, reliable and smart heating easier than ever before.

UltraGas® 2 D (250 - 3100)

Set consisting of two sophisticated gas condensing boilers and one shared flue gas line for heating and generating hot water, available with output ratings from 250 kW to 3100 kW. Floor-mounted, continuous power adjustment, with Hoval TopTronic® E system controller.

Range of applications: blocks of flats, commercial, office and industrial buildings, schools and sports facilities, hotels, district heating networks – for renovations and new buildings.







Suitable for biomethane and, in future, also hydrogen
Cost-effective operation
Secure investment
Compact transport and installation dimensions

The new benchmark

"The UltraGas® 2 double boiler is the perfect solution for very high output requirements, if maximum operational safety is required or if there is not much space available for transport and bringing into position.


Double boilers have been designed to work as one functional unit with a shared flue gas line.

Two complete boilers communicate with one another via their TopTronic® E controller and split the job of providing heat between themselves. Both boilers run in partial load operation – an excellent, economical operating state – whereas one boiler operating alone would have to go full throttle, thus increasing consumption and shortening service life. If a boiler should ever fail unexpectedly, the second would temporarily take over and provide heat until its sibling was ready to go once more. "

Cost-effective operation

"The UltraGas® 2 is an impressive product whose minor refinements have a major impact.

The innovative Hoval TurboFer® heat exchanger allows for operating temperatures of up to 95°C. It also has a specially developed heating surface that transfers heat even more effectively than other designs.
The separate high-temperature and low-temperature returns are another way to ensure cost-effective operation. This separation means the heating water is returned to the correct place in the boiler, thus producing optimum water-side temperature stratification inside it. Using the high-temperature and low-temperature returns makes the system more efficient.

A flow temperature sensor optimises operation of the heating system even further. This sensor records the precise flow temperature, enabling it to improve the control response. The through-flow is more constant and the return temperature is lower. The useful heat is utilised in the best way possible. This boiler’s increased efficiency and energy savings of up to 20% compared to a conventional gas boiler enable it to save the customer money. The investment is recovered in just a few years."

Secure investment

The Hoval UltraGas® series has been a success story for over 20 years, with owners all over the world appreciating its durability. The secret to its long life can be found in the high-quality stainless steel used on the water side. The UltraGas® 2 handles even large differences between the flow and return temperatures with no problem at all. Hoval provides an extended warranty for the boiler body, giving owners the confidence to make a long-term investment in a reliable design.

Compact and simple installation

The UltraGas® 2 has compact dimensions, making transport easy. It fits through any standard door. It also scores highly when it comes to integration into the heating system, since it features a large water capacity and the two separate returns for low and high temperature. There is no need for system components such as a circulating pump or a hydraulic separator; installation is simpler and takes up less space. The unit for neutralising the condensate that is produced is compact too.
The gas boiler can also operate on biomethane and hydrogen, equipping it for the ongoing energy transition from gas to biomethane and for a hydrogen-powered future. Alternative, sustainable energy sources, such as solar, pellets and heat pumps, are easy to integrate into the new generation of system boilers. All of these factors make the UltraGas® 2 a future-proof investment and reduce the CO2 emissions.


Perfect integration

The TopTronic® E control also helps to make additional savings. Its wide range of functions include easy adjustment operating times to facilitate energy-conscious heating. The energy consumption display and the counter module help you to keep a permanent eye on costs. To allow for simple control while you are out-and-about and to enable you to receive system messages in real time, you can opt for various gateway modules for an Internet connection, the smartphone app and HovalConnect. The Hoval control system HovalSupervisor visualises, controls and monitors the operation of multiple UltraGas® plants. This enables you to optimise the energy production process, right through to the individual processes in the entire energy grid.