Protherm Gepard Condens 18/25 MKV

Product detailed description

Frequently asked questions

• How exactly do I choose the output of a PROTHERM 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.