Not only do the new Riello RDB BX low NOx oil burners comply with current ErP regulations, they have also been designed in a way to maintain familiarity for the installer.
RDB BX low NOx burners have the same first line spares as earlier models (oil pump, control box, motor, flame sensors and capacitor) to simplify installers’ stock control.
One notable addition to the BX burner is an adjustable combustion head. Combustion head adjustment should not be necessary during commissioning as the setting has been defined and pre-set from production. However, there may be occasions where the flue configuration may require a small adjustment. Closing the head can assist in reducing CO levels or opening the head can give a more reliable ignition. Recirculation tubes for some applications are fitted to the burners to control and reduce CO formation.
It should be noted that, due to the improved combustion technology, RDB BX burners have been designed to operate with typical CO2 values of 12.0 – 12.5%, so it is important that this is checked during commissioning – as with any commissioning of course! Installers should also be aware of an important change to flame sensors, driving a change away from current photocells. Directive 2011/65/EU prohibits the use of certain substances, including the cadmium sulphide generally used in photocells. As a result, new flame sensors are being introduced on RDB BX, RL and R40 models. The dimensions and connections are the same as the current versions.
It is important that the correct new flame sensor is used with the relevant burner control i.e. analogue or digital. Flame sensors for digital models are now different from those of analogue models as shown in the table bottom right.
In addition, some boiler manufacturers require the use of a digital burner control box, rather than analogue, to support functions such as remote reset of burner lock-out and post- purge function after firing. If installers are unsure of what type of control box is fitted, then please follow the manufacturer’s instructions. As a guide, it is useful to know that analogue controls have a red lock-out button and on digital controls the button is clear.