EN 298

device by which the presence of a flame is detected and signalled;
it can consist of a flame sensor, an amplifier and a relay for signal transmission. These parts, with the possible exception of the actual flame sensor, can be assembled in a single housing for use in conjunction with a programming unit

actual flame-sensing element, the output signal or value of which is used as the input for the flame detector amplifier.

physical value monitored by the flame sensor

signal given by the flame detector device in case of sensed flame

condition which occurs when the flame signal indicates the presence of a flame when in reality no flame is present

unit which reacts to signals from control and safety devices, gives control commands, controls the start-up sequence, supervises the burner operation and causes controlled shut-down, and if necessary safety shut-down and lock-out; the programming unit follows a predetermined sequence of actions and always operates in conjunction with a flame detector device

system comprising at least a programming unit and all the elements of a flame detector device;
the various functions of an automatic burner control system can be in one or more housings

stage, where the system is not in lock-out position, has not yet received the start signal but can proceed with the startup
sequence when required;
at this stage, the output terminals for any automatic shut-off valve and ignition device are not energized

signal e. g. from a thermostat, which releases the system from its start position and commences the predetermined programme

sequence of control operations determined by the programming unit involving switching on, starting up, supervising and switching off the burner; safety actions such as safety shut down and lock out are also part of the programme

forced introduction of air through the combustion chamber and flue passages in order to displace any remaining fuel/air mixture and/or products of combustion

purge which takes place between the start signal and the energization of the ignition device

purge which takes place immediately following shut-down

interval between the pilot gas valve, the start gas valve or main gas valve, as applicable, being energized and the pilot gas valve, start gas valve or main gas valve, as applicable, being de-energized if the flame detector signals the absence of a flame

NOTE Where there is no second safety time, this is called the safety time.

where there is a first safety time applicable to either a pilot 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

burner where the primary air required for combustion is provided by the action of the gas and the secondary air is freely available from the surroundings

burner in which some or all of the air required for the combustion is supplied by means of a fan (i. e. forced draught or induced draught)

position of the system in which the burner is in normal operation under the supervision of the programming unit and its flame detector device

process by which the power to the gas shut-off valve(s) is removed before any other action takes place, e. g. as a result of the action of a controlling function

process which is effected immediately following the response of a protection device or the detection of a fault in the automatic burner control system and puts the burner out of operation; the resulting state of the system is defined by deactivated terminals for the gas shut-off valves and the ignition device

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

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 main power and its subsequent restoration

process by which, following loss of flame signal, the ignition device will be switched on again without total interruption of the gas supply

process by which, after a safety shut-down a full start-up sequence is automatically repeated

for burners without fans, the interval between the start signal being given and the energization of the ignition device or gas valves, which ever comes first; during this time natural ventilation of the combustion chamber and the flue passages can take place

period during which purge takes place at the proven air rate prior to the energization of the ignition device or gas valves, which ever comes first

period during which purge takes place at the proven air rate between any shut-down and the moment the fan is switched off

period during which purging of the combustion chamber takes place at the proven air rate after unsuccessful ignition and prior to the next recycle attempt

period during which natural ventilation of the combustion chamber takes place after unsuccessful ignition and prior to the next recycle attempt

sequence of actions executed by the system which brings the burner from the start position to the running position

part of the start-up sequence which allows the release of start gas into the combustion chamber

part of the start-up sequence which allows the release of further gas into the combustion chamber (if applicable)

systems that are designed to remain in the running position for longer than 24 h without interruption

systems that are designed to remain in the running position for less than 24 h

automatic internal function of the system which checks the operation of the flame detector device

condition which occurs when the air flow sensor indicates the presence of air flow when in reality no air flow is present

process of monitoring the ignition spark

interval between the end of the first safety time and the beginning of the second safety time which is used to prove that the pilot or gas flame is stable

first stage that is ignited prior to ignition of the main flame and is shut off simultaneously with it

first stage that is ignited each time the burner is started up and which is extinguished at the end of the main flame establishment period