Vaillant VU 246/5-3 ecoTEC pro

Product detailed description

Vaillant VU 246/5-3 ecoTEC pro
- wall-hung condensing boiler with the option to connect an external cylinder
- output: 6,9 - 25,5 kW 
- standardised gas efficiency rating: 108 %
- modulation: 1:7

• heating and hot water preparation 
• designed for underfloor and radiator heating
• space-saving - the boilers feature compact dimensions
• can be installed in attic spaces
• operation independent of, or dependent on, the room volume (combustion air supply) 

• Aqua-Power Plus function up to 21% higher output for hot water preparation
• NOx value in flue gas pod 60 mg/m3
• standardised efficiency rating 109 %
• continuous output modulation
• simple backlit display with symbols
• Thermo-Compact module fitted with a stainless steel burner and fan
• automatic diagnostic system (digital display of operating states and analysis of the boiler mode)
• the heating system can be prepared before the boiler itself is installed
• ready for connection of a storage water heater
• the VU boiler already includes an built-in diverter valve
• reduced electricity consumption

• two-stage, energy-efficient circulation pump
• expansion vessel
• automatic air vent
• condensate drain (siphon)
• integral stainless-steel condensing heat exchanger
• built-in control for an indirectly heated cylinder
• electronic setting of reduced heating output
• built-in composite three-way diverter valve 

Parameters

Frequently asked questions

• How exactly do I choose the output of a VAILLANT condensing boiler? The starting point is the calculated heat loss of the building being heated (most reliably taken from the project documentation or an energy certificate). If you don't have a project, you can roughly estimate 60-100 W per m² of floor area for a normally insulated house built after 2000, or 100-150 W/m² for an older, uninsulated house - the exact figure varies depending on the number of floors, ceiling height, the number and quality of windows, and the building's orientation. An oversized boiler switches on and off more often (so-called cycling), which shortens its lifespan and reduces efficiency; an undersized boiler, on the other hand, cannot heat the house sufficiently on frosty days.
• Why is a condensing boiler more economical than a conventional one? A condensing boiler also makes use of the heat hidden in the water vapour produced when gas is burned - in a conventional boiler this vapour escapes unused through the flue, while in a condensing boiler it is cooled below the so-called dew point, the vapour condenses, and the released heat is returned to the heating circuit. Thanks to this, condensing boilers achieve an efficiency of roughly 105-110% relative to the calorific value of the gas, compared to the usual 85-92% for conventional boilers.
• What type of flue gas exhaust does this boiler need? Most modern condensing boilers are so-called turbo boilers (with a sealed combustion chamber) and require a concentric (coaxial) or separate flue gas exhaust and combustion air intake routed through an external wall or the roof - so a functional chimney is not required. You will find the exact type and maximum length of the flue (based on a diameter of 60/100 or 80/125 mm) in the technical documentation for the specific model, or you can consult our customer service.
• What does the ErP energy class shown for the boiler mean? This is the mandatory efficiency label for heating appliances under the EU ErP (Ecodesign) directive, similar to the energy labels on refrigerators. Condensing boilers commonly achieve class A, or even higher in combination with room controls (e.g. A+ when using weather-compensated control and a room thermostat).
• Can I install and connect this boiler myself? No. Connecting to the natural gas supply, the electrical network and the flue gas exhaust must, by law, be carried out exclusively by a person with the relevant qualification (most often an authorised service technician of the given brand or a gas appliance inspection technician). After installation, the boiler must be commissioned by the manufacturer's authorised service, which is usually also a condition for the warranty to be valid.
• What about servicing and the warranty? Most manufacturers require a regular annual service inspection by an authorised service provider so that the warranty remains valid even after its standard expiry (an extended warranty subject to regular servicing is common especially for the Vaillant, Protherm and Viessmann brands). You will find the exact warranty terms in the warranty certificate supplied with the boiler.
• What is included in the delivery of this specific product? The exact contents of the package (the boiler itself, possibly a hot water tank, room controls and other accessories in the case of a set) are stated in the product name and in its technical parameters above on this page.