Glossary of Terms

An app is a software application that is downloaded by a user to a mobile device. Vaillant has produced apps for Apple and Android devices (downloadable from the App Store and Google Play) so that its vSMART and VRC 700 heating controls can be controlled from a mobile phone or tablet.

This is a feature of the vSMART and VRT350 and VRC700 controllers that means the clock is reset automatically to take account of British daylight saving time.

Vaillant uses a blue, backlit display in its digital displays. This proven technology offers outstanding contrast for clear information and low energy consumption.

Boiler Plus is legislation introduced by the UK Government in 2018 as part of its ‘Heat in Buildings’ programme. This programme was designed to improve the ways homes in the UK use energy by increasing the efficiency of their heating systems. The introduction of Boiler Plus is the first major piece of legislation since the UK went “all-condensing” in 2005 - becoming the first country to do so in the process.

All boilers fitted in the UK must now have a minimum ErP efficiency of 92% and all installations must have time and temperature controls fitted, if they aren't already present and working correctly. For boilers that don’t already meet the target 92% efficiency, controls can be added to ensure compliance with this legislation. Further information on which Vaillant boilers already comply with Boiler Plus legislation and which controls should be fitted to ensure compliance, click here.

A combi or combination boiler is an all-in one heating appliance that doesn’t need a storage tank. It’s perfect for homes with one bathroom or where there’s limited space. Heating systems run by combination boilers only heat the water they use, so they’re economical too!

All boilers fitted in the UK have to be condensing boilers. They work by condensing water vapour in the exhaust gases so that they recover the latent heat of vaporisation, which would otherwise have been wasted. The condensed liquid vapour leaves the system via the condensate pipe.

Smart heating controls can monitor your energy consumption patterns. The apps that are available for the vSMART and VRC700/f are able to display your energy consumption on your mobile phone or tablet to give you detailed insights into the performance of your boiler and your energy usage. This means you can set your controls with a view to reducing your energy use, ensuring your boiler is working at its most efficient level, thereby saving energy and money.

eBUS is the proprietary language used by Vaillant products so they can ‘talk’ to each other. It is this intelligent communication that allows Vaillant boilers to carry out more complex decisions rather than just turning on and off.

Products that use energy, such as boilers, are rated according to the energy they consume. The ratings usually range from A+++ to G, depending on the product. The ErP rating has to be displayed on the product.

An expansion vessel is a small tank fitted to a sealed heating system that provides room for expansion of the water as it is heated. This is to prevent the system pressure getting too high.

During combustion, all boilers produce gasses that need to be emitted outside of your home. The pipework for this is known as a flue.

A heat exchanger is used inside a boiler to transfer heat from the gas burner to the water in the system/radiators. They are also used in a combi boiler to heat the hot water for your hot taps and showers. Heat exchangers can be made from either aluminium, or stainless steel. Stainless steel heat exchangers offer superior heat transfer and highly efficient performance.

This function can be set to ensure your boiler is turned off while you’re away and turns on again when you return.

Internet controls give all of the same functionality as a programmable room thermostat. They offer control at the point of use as well as remote control via an app (with a smartphone or tablet).

Some boilers can be converted to run on LPG where a natural gas supply is not available (an off-gas area). LPG gas for central heating is stored in large cylinders adjacent to the property. Some boilers require an LPG conversion kit (purchased separately) and some are compliant out of the box.

Also known as a conventional or regular boiler, an open vent boiler is part of an open vent heating system that includes feed and expansion tanks in the loft (that are open to atmospheric pressure) as well as a storage cylinder. The hot water is heated via the storage cylinder.

A Plug-in Timer/Programmer is a device that switches your heating on and off at specific times set by the user. These can be mechanical or digital and may only allow times for a 24hr period to be set or each day programmed individually.

A programmable room thermostat combines the functionality of a room thermostat and timer/programmer. It ensure the temperature is controlled as per the programmed time setting.

A traditional Room Thermostat senses the temperature of the room and sends a command to the boiler to turn on. It instructs the boiler to work at 100% until the required set temperature is achieved.

The setback temperature is the temperature you would like the property to remain at during out of hours operation. A setback temperature is important as it allows the property to heat up to the desired temperature during active hours without using as much energy as heating the property from a lower temperature. Secondly, the setback temperature prevents moisture developing in properties, which could otherwise lead to the development of damp patches. Moisture forms at temperatures below 14 degrees Celsius so a typical setback temperature is 16 degrees Celsius.

A system boiler heats water directly from the mains for your central heating system and hot water, which it stores in a cylinder (rather than a tank in the loft). They are perfect for larger homes that may have more than one bathroom.

A thermostat controls the temperature of your heating system, ensuring the system heats to maintain a set temperature. Thermostats can be standalone or form part of a control.

A TRV is a self-regulating valve that fits directly onto the radiator. It controls the temperature in the radiator by changing the flow of hot water to the radiator. Vaillant manufactures ambiSENSE TRVs that can be controlled via an app (when fitted alongside a compatible control system, such as the VRC700).

The VDE institute is an independent and neutral European technical-scientific association that assesses products and services for smart home security. All of Vaillant’s products have been rigorously tested and have met VDE’s strict testing criteria for approval by the Institute. You can therefore reset assured that any data used by Vaillant products is protected and secure.