Rinnai discusses the use of external and internal gas-fired appliances

Rinnai Operations Director, Chris Goggin discusses the why and the where of using ‘E’ (external) – and ‘I’ (internal) gas-fired appliances to suit the application.

Gas-fired appliances such as hot water heating units or domestic or light commercial boilers tend to be wall hung on the interior of a site. Having a unit sited internally on a kitchen wall or a plant room makes for convenience for the end-user and for the installer or contractor in terms of installation, maintenance or servicing.

However, external models of hot water heating units have become increasingly popular. We are seeing more and more units sold as installers seem to be favouring external siting for a variety of reasons.

Firstly, having a gas-fired unit internally has its own restrictions – lack of internal space, flueing restrictions and impediments, exact siting for installer convenience, inspections etc.

Whereas, on external units a whole stack of advantages come into play – starting with the fact that it is a gas-fired appliance and it is outside habitable space; and with no need for a flue there’s greater flexibility on exactly where you place the unit; it is easier to service and maintain; all units have robust casings and comprehensive weather controls, for example a Rinnai external appliance is frost protected down to minus 25ºC.

All these factors add up to possible economies for the end-user and ease of installation for the installer.

Rinnai offer several units in both external – ‘E’ – and internal – ‘I’ – models. They are in the more heavy-duty part of our product range – 1600, 1500, 55 but also at the smaller end – the 17e.

Rinnai’s HDC1600i/e low NOx, gas-fired continuous flow water heater, delivers commercial qualities of hot water, up to 37 litres per minute on demand – to any site and application. And they are ErP ‘A’ rated. The Rinnai external version HDC1200e gives end users 105.5% net efficiency* because the condensing process delivers up to 95% thermal efficiency, translating to significant energy savings when compared to standard tankless water heaters.

All of which makes the HDC continuous flow hot water range by far the best option for all types of applications. With a continuous flow water heater you can never run out of hot water no matter how many individual baths or showers or delivery points are being used simultaneously.

The only time the unit is using energy is when there is a demand, in other words it is only burning gas when a tap or shower is being run and, design improvements by Rinnai have increased the lowered NOx levels and increased efficiencies to market ready levels.

The Rinnai 17e is designed for use directly off the mains, with no need for large, ungainly storage vessels. Weighing just 17kg and measuring 503mmH x 355.6mmW x 181mmD the Rinnai 17e has been developed to allow maximum flexibility as it can be easily mounted on an external wall thereby eliminating the need for flueing and freeing up valuable interior space. This feature gives greater flexibility at the design stage and can offer an alternative solution where flue runs are problematic or internal space is not available.

A range of external ancillary items including a pipe cover box and security cage are available where necessary. Capable of flow rates of up to 510 litres per hour at a 50°C rise, the 17e is suitable for multiple applications, such as cafés, small restaurants and kitchen facilities.