Be in the know with blue flame boiler technology
Be in the know with blue flame boiler technology

Blue flame burner technology has featured within the oil boiler market for a few years now. With their cleaner burners, blue flame boilers provide heating engineers with a solution to fit efficient oil boilers with significantly lower NOx emissions within their customers’ homes. Not turned to the blue side yet? Here are a few useful tips to help you better understand blue flame oil boiler technology.

Everyone is probably aware of the distinct blue flame and the longer blast tube or combustion head associated with a typical blue flame burner. While there are differences between blue and yellow flame burners, not everything is completely new – for example, with the Riello RDB BG BLU burner which features in Grant’s VortexBlue boilers, there are many similarities with the Riello RDB yellow flame burner such as the air inlet box and adjuster, fan housing, and oil pump. Installers experienced with working with traditional yellow flame burners will therefore easily identify the familiar characteristics of a blue flame burner’s construction which should straightaway make this advanced technology less daunting.

There are differences, however, aside from the obvious two features mentioned at the beginning of this blog. Blue flame burners use an ultraviolet flame sensor instead of a photo-resister photocell used in other burners, and they feature a digital (rather than analogue) control box. When installing a boiler with a blue flame burner, heating engineers do need to take a couple considerations into account and we will touch on these a little later on. Before that, let me first explain how blue flame technology works.

Blue flame explained in a nutshell
The combustion process that takes place within a blue flame burner differs to and is much cleaner than in standard yellow flame burners. The combustion gases within a blue flame burner are re-circulated through a specially designed longer blast tube which has a ring of slots within the combustion chamber. This design allows the combustion gases to mix with atomised droplets of fuel and fresh air (oxygen) drawn in through the burner, to produce a clean blue flame which has much lower NOx emissions. The important thing to remember is that blue flame technology remains highly efficient with the added benefit of significantly lower levels of NOx emissions, adhering to current emissions limits and anticipating forthcoming lower emissions targets expected in 2022.

What to factor in during installation
Heating engineers fitting a blue flame boiler need to understand the differences on the burner. On the Riello RDB BLU burners there is a digital control box. This has a clear reset button which changes colour to indicate the operating status of the burner as well as providing diagnostics guidance.

Another difference from the Riello RDB yellow flame burners is that the blue flame burners have a fan post purge operation. In order to provide this function, the control box requires a Permanent Live as well as a Switched Live and this requirement is provided via the boiler’s circuit board (which in Grant VortexBlue boilers is the same as the circuit board used in the Vortex Combi range).

As previously mentioned, a UV flame sensor is used with the blue flame burners because a conventional photocell cannot see or detect the blue flame. From an installation perspective, the installer does not need to do anything differently.

Another important difference with a blue flame burner is it has a different ignition electrode assembly. The RDB BLU electrodes are attached to, and removed with, the burner blast tube. They are longer and have different settings to the shorter electrodes in other burners. With the RDB BLU burners, there should be 5mm between the tips in the electrodes and 63mm in front of the nozzle.

As with all installations, engineers must be familiar with the individual burner settings of the specific model they are working with and these can be found in the installation manual supplied with the boiler (as well as online). And, the good news is when it comes to commissioning and servicing a blue flame boiler, the procedures are identical to those used for yellow flame RDB burners and, furthermore, the commissioning engineer does not need to measure the NOx levels in the flue gases.

Benefits for your customers
With their ultra-low NOx emissions levels, blue flame oil-fired boilers are a greener alternative to traditional yellow flamed oil-fired boiler models. Installers can therefore provide their customers with a more sustainable oil boiler when they are looking for a like-for-like boiler replacement. Furthermore, this greener technology is often accompanied by lengthy guarantees with Grant’s VortexBlue oil-fired boilers available with a ten year guarantee when installed by a G1 Installer (T&Cs apply). In conclusion, installers should not be afraid of blue flame burner technology but instead, become familiar with the differences and add it to their offering for customers.

A series of videos on the VortexBlue oil-fired boiler range can be viewed via Grant UK's YouTube Library - please click here to view

Be in the know with blue flame boiler technology
Credit: Grant UK
The Riello RDB BG BLU burner which features in Grant’s VortexBlue boilers
Phil Stanley
Training Manager at Grant UK