Viessmann Boilers

How they work: A combi boiler is a single, compact unit that heats water directly from the mains as needed. It provides both central heating and instant hot water on demand, eliminating the need for a separate hot water cylinder or a cold water tank in the loft.

Best for: Smaller to medium-sized homes with one or two bathrooms and a standard hot water demand. They are ideal for saving space and are highly efficient as they only heat water when a hot water tap is turned on.

How they work: A system boiler heats water for the central heating system and also for a separate hot water storage cylinder, typically located in an airing cupboard. Unlike a conventional boiler, a system boiler gets its water supply directly from the mains, so it doesn't require a cold water tank in the loft.

Best for: Medium to large homes with multiple bathrooms where there is a high hot water demand. The stored hot water allows for several taps or showers to be used simultaneously with a strong, consistent flow.

How they work: A heat-only boiler is the traditional type of heating system. It provides hot water for your central heating system and a separate hot water cylinder, but it also requires a cold water storage tank in the loft. This tank feeds water to both the boiler and the hot water cylinder.

Best for: Larger homes that have an existing traditional heating system. They are particularly well-suited for properties with older radiator systems and pipework that may not be able to handle the high pressure of a system or combi boiler. Replacing an old conventional boiler with a new one of the same type can be a cost-effective solution as it avoids changes to the existing pipework.

How they work: This is a hybrid model that combines the features of a combi and a system boiler. It's a single unit like a combi, but it has a small, integrated hot water storage tank. This allows it to provide a rapid and powerful flow of hot water, like a system boiler, without the need for a large separate cylinder.

Best for: Homes with high hot water demand but limited space for a full-sized hot water cylinder. They are perfect for households that often use multiple hot water outlets at once.

Exceptional Efficiency: Many Viessmann boilers are A-rated for energy efficiency, with some achieving up to 98% efficiency, which can lead to notable savings on energy bills.

Reduced Emissions: The efficient combustion and advanced burner technology (like the MatriX-Plus burner in some models) contribute to lower CO2 and NOx emissions, reducing the homeowner's carbon footprint.

Hydrogen-Ready Boilers: Many of Viessmann's current models, including the popular Vitodens 100-W, are "hydrogen-ready" and are certified to operate on a natural gas mix containing up to 20% hydrogen. This means they are a safe investment for the transition period.

100% Hydrogen Boilers: Viessmann is also actively developing and testing prototypes of boilers that can run on 100% pure hydrogen, which could be converted from natural gas with a simple, cost-effective burner replacement. This provides a clear, future-proof path for homeowners to adapt to new fuel sources without a full boiler replacement.

ViCare App: Many of their boilers come with built-in Wi-Fi or can be easily connected using an add-on module. This allows the homeowner to control their heating system from a smartphone or tablet using the ViCare app.

Remote Control: The app enables users to adjust temperature, set heating schedules, and switch to "party mode" or "away mode" from anywhere.

Maintenance and Monitoring: The smart features also benefit the installer. They can remotely monitor the boiler's performance and receive notifications about potential faults, allowing for proactive maintenance and quicker service.

Viessmann Vitodens 050-W: This is Viessmann's entry-level combi boiler, and it's an excellent choice for smaller properties. It's a reliable, highly efficient, and quiet boiler that provides heating and hot water on demand. Its compact size allows it to be installed easily in a kitchen cupboard, making it perfect for homes with limited space.

Viessmann Vitodens 100-W: This is Viessmann's most popular and highly-regarded model. It strikes an excellent balance between cost, performance, and features. The Vitodens 100-W is available in higher output versions suitable for homes with multiple bathrooms. It's also available as a system or heat-only boiler, which can be ideal for a medium-sized home that wants the benefit of a hot water cylinder for more consistent pressure.

Viessmann Vitodens 200-W: This is Viessmann's premium model and the top choice for larger homes. It offers the highest efficiency (up to 98%), a wide modulation range for precise heating control, and is packed with advanced features like a colour touchscreen and a powerful fan. It’s available as a system or combi boiler, with the system boiler option being the most common choice for large properties with a hot water cylinder.

Standard Warranty: Many Viessmann residential boilers, particularly within the popular Vitodens range, come with a standard 5 or 7-year warranty on parts and labour.

Extended Warranty: You can often extend this warranty for a longer period, typically up to 10 or even 12 years. This is usually conditional on the boiler being installed by a Viessmann-trained installer (often called a "Viessmann Partner" or "accredited installer") and being registered with Viessmann within a specific timeframe (e.g. 30 days of installation).

Warranty Conditions: To keep the warranty valid, you must have the boiler serviced annually by a Gas Safe registered engineer, with the details recorded in the service logbook. The warranty covers manufacturing or material defects but does not cover issues caused by improper installation, lack of maintenance, or external factors like freezing pipes.

Dedicated Customer Care: Viessmann has a UK-based customer care team that can be reached by phone or email. They can help with booking engineer visits, troubleshooting, and general inquiries.

Specialised Engineers: For warranty claims or repairs, Viessmann employs its own dedicated team of Gas Safe-registered engineers who are exclusively trained to work on Viessmann products. This ensures the highest level of expertise and often a quick resolution, as they carry an extensive stock of spare parts.

Online Resources: Viessmann's website offers a wealth of resources, including troubleshooting guides, fault code identifiers, and FAQs, allowing homeowners to resolve minor issues themselves.

How long does installation take? A straightforward "like-for-like" replacement of a combi boiler can often be completed in a single day. A more complex installation, such as converting a conventional system to a combi or moving the boiler's location, may take two or more days.

Do I need a Gas Safe-registered engineer? Yes. By law, any installation, service, or repair of a gas boiler must be carried out by a Gas Safe-registered engineer. This is non-negotiable and is also a condition for maintaining your warranty.

What about the condensate pipe? A modern condensing boiler, like the Viessmann Vitodens series, produces condensate (a small amount of acidic water). This needs to be safely drained away. It is recommended that the condensate pipe is installed internally to prevent it from freezing in cold weather, which can cause the boiler to shut down.

Can I install the boiler myself? No. As mentioned, this is not only illegal but will also void the manufacturer's warranty and can be extremely dangerous.

What about my old boiler? Your installer will usually be responsible for decommissioning and safely disposing of your old boiler and any associated tanks or cylinders, ensuring they are recycled or disposed of properly.