BS EN 621:2009 pdf free download – Non-domestic gas- fired forced convection air heaters for space heating not exceeding a net heat input of 300 kW, without a fan to assist transportation of combustion air and/or combustion products.
3.3.7
light-back
entry of a flame into the body of the burner
3.3.8
light-back at the injector
ignition of the gas at the injector, either as a result of light-back into the burner or by the propagation of a flame outside the burner
3.3.9
sooti ng
phenomenon appearing during incomplete combustion and characterized by deposits of soot on the surfaces or parts in contact with the combustion products or with the flame
3.3.10
yellow tipping
yellowing of the tip of the blue cone of an aerated flame
3.3.11
first safety time
interval between the ignition burner gas valve, the start gas valve or main gas valve, as applicable, being energized and the ignition burner gas valve, start gas valve or main gas valve, as applicable, being deenergized if the flame detector signals the absence of a flame at the end of this interval
NOTE Where there is no second safety time, this is called the safety time.
3.3.12
second safety time
where there is a first safety time to either a ignition burner or start gas flame only, the interval between the main gas valve being energized and the main gas valve being de-energized if the flame detector signals the absence of a flame
3.3.13
start gas
gas that is supplied at the start gas rate to establish the start gas flame
3.3.14
start gas rate
the restricted gas flow rate admitted either to a separate ignition burner or to the main burner during the first safety time
3.3.15
start gas flame
flame established at the start gas rate either at the main burner or at a separate ignition burner
3.3.16
running condition of the system
condition of the system in which the burner is in normal operation under the supervision of the programming unit and its flame detector device
3.3.17
automatic burner system
burner system in which, when starting from the completely shut-down condition, the gas is ignited and the flame is detected and proved without manual intervention
3.3.18
non-automatic burner system
burner system with an ignition burner which is ignited under manual supervision
3.3.19
controlled shut-down
process by which the power to the gas shut-off valve(s) is removed immediately, e.g. as a result of the action of a controlling function
[EN 298:2003]
3.3.20
safety shut-down
process which is effected immediately following the response of a protection device or a fault in the automatic burner control system and puts the burner out of operation
NOTE The resulting state of the system is defined by deactivated terminals for the gas shut-off valves and the ignition device. [EN 298:2003]
3.3.21 Lock-out
3.3.21.1
non-volatile lock-out
safety shut-down condition of the system, such that a restart can only be accomplished by a manual reset of the system and by no other means
[EN 298:2003]
3.3.21.2
volatile lock-out
safety shut-down condition of the system, such that a restart can only be accomplished by either the manual reset of the system or an interruption of the electrical supply and its subsequent restoration
[EN 298:2003]
3.3.22
spark restoration
process by which, after disappearance of the flame signal, the ignition device is energized again without the gas supply having been totally interrupted
NOTE This process ends with the restoration of the wnning condition or, if there is no flame signal at the end of the safety time, with non-volatile lock-out.