21
6
Information for Mounting and Installation
6.1.3
Basic mounting instructions
NOTICE
The cables are designed for a special temperature range (see chapter
Do not open the devices in temperatures below -20 °C/-4 °F.
NOTICE
For the installation of an extension cable on site, make sure to use a
separate, shielded ex-
tensionable
. Moreover, provide for good continuity of the shield and make sure that the shield
and functional earthing (FPE) are connected properly.
In order to reduce the risk of electromagnetic interference it is recommended that the supply
cable and extension cable, if used, are installed in separate containment away from any main
wiring (e.g. ignition lines, electrical motors, contactors, frequency inverters). Parallel cable
routing with mains cables should be strictly avoided.
NOTICE
Very high levels of electromagnetic radiated noise may result in sporadic problems in flame
detection, or may even avoid proper detection at all.
NOTICE
The radiation emitted by a flame contains an element of flicker (pulsating).
This characteristic is a result of the processes that occur during combustion. This oscillation
(flame frequency) is used for flame monitoring. The flame detector should be installed at the
burner viewing port using a suitable mounting device to ensure that the burner flame remains
perfectly visible throughout the full modulating/operating range of the furnace. To install a se-
lective monitoring device the viewing port should be located such that the flame sensor can
be aligned to detect the base of the flame adjacent to the burner mouth (perhaps 'head' might
be better). The detector should be aligned so that it cannot 'look' directly into adjacent flames
or flames located on the opposite side of the furnace. Consideration should also be given to
ensure that background flames, such as coal, wood and waste, cannot be detected.
