UltraGas® 2 (125-1550)
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.

Heating flow

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

TurboFer® heat exchanger

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

Separate high and low temperature returns

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

Width for bringing into position smaller than a standard door

including its pallet, the width needed to bring the UltraGas® 2 into position measures a maximum of 790 mm. This means that it fits through any standard doorway.

UltraGas® 2 gas condensing boiler (125-1550)

Sophisticated gas condensing boiler for heating and generating hot water, available with output ratings from 125 kW to 1550 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 – for renovations and new buildings.

Cost-effective operation
Ready for 20% Hydrogen blend and will be certified for 100% Hydrogen
Secure investment
Compact transport and installation dimensions

The new benchmark

The UltraGas® 2 gas condensing boiler meets the highest standards when it comes to energy efficiency and cost effectiveness. Its technical and design-related details ensure maximum efficiency while reducing gas consumption. 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.

Cost-effective operation

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.

Smart features

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.