Vaillant VUW 26CS/1-5 ecoTEC plus IoniDetect - with instant DHW heating

Product detailed description

Vaillant VUW 26CS/1-5 ecoTEC plus IoniDetect
- wall-mounted condensing boiler with instant DHW heating
- output: 2,8 - 21,6 kW (25 kW for DHW)
- normalised gas utilisation efficiency: 109,5%
- modulation: 1:10

We have further improved our best-selling boiler – using the latest technologies that provide a reliable heating solution for the future. Its optimal price-to-performance ratio makes it a truly good choice. Proven quality guarantees a long service life, while innovative features increase its efficiency. All this contributes to a significant reduction in your costs.

Frequently asked questions

• How exactly do I choose the output of a VAILLANT condensing boiler? The basis is the calculated heat loss of the heated building (most reliably from the project documentation or an energy certificate). If you don’t have a project, you can roughly estimate around 60-100 W per m² of floor area for a commonly insulated house built after 2000, or 100-150 W/m² for an older, non-insulated house – the exact figure, however, differs depending on the number of floors, room height, the number and quality of windows, and the building’s orientation. A boiler oversized for the required output switches on and off more often (so-called cycling), which shortens its service life and reduces efficiency; conversely, an undersized boiler cannot heat the house sufficiently on freezing days.
• Why is a condensing boiler more economical than a conventional one? A condensing boiler also uses the heat hidden in the water vapour created during gas combustion – in a conventional boiler this escapes unused through the chimney, while in a condensing boiler it is cooled below the so-called dew point, the vapour condenses, and the released heat is returned back into the heating circuit. Thanks to this, condensing boilers achieve an efficiency of approximately 105-110% relative to the calorific value of the gas, compared to the usual 85-92% for conventional boilers.
• What type of flue gas discharge does this boiler need? Most modern condensing boilers are so-called turbo boilers (with a sealed combustion chamber) and require a concentric or separate flue gas discharge and combustion air supply routed through the outer wall or roof – so they don’t need a functional chimney. You can find the exact type and maximum discharge length (by diameter 60/100 or 80/125 mm) in the technical documentation for the specific model, or consult our customer service.
• What does the ErP energy class stated for the boiler mean? This is the mandatory efficiency labelling of heating appliances under the EU ErP (Ecodesign) directive, similar to the energy labels on refrigerators. Condensing boilers commonly achieve class A, or higher in combination with room controls (e.g. A+ when using weather-compensation control and a room thermostat).
• How does a combi boiler with instant DHW heating work? When there is a demand for hot water, the boiler temporarily switches priority from heating to heating the water flowing through the built-in plate heat exchanger – hot water is thus available practically immediately and in unlimited quantity, however the heating output is limited by the instantaneous flow rate (usually sufficient for one simultaneous draw-off point, e.g. a shower).
• Can I install and connect this boiler myself? No. Connection to the natural gas supply, the electrical mains, and the flue gas discharge is by law exclusively the responsibility of a person holding the relevant authorisation (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 remain valid.
• What about service and warranty? Most manufacturers require a regular annual service inspection by an authorised service provider in order to keep the warranty valid even after its standard expiry (an extended warranty for regular servicing is common especially for the brands Vaillant, Protherm, Viessmann). You can 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 package contents (the boiler itself, possibly a hot water cylinder, room controls, and other accessories in case of a set) are stated in the product name and in its technical parameters above on this page.