Gas fired igniter ZA0 / ZDA0
Functional characteristics and structure
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Status: 11-2018
The outer tube (6) is screwed to the power head (1) and can be
removed or depending on the position of the air supply pipe can be
turned by 90°.
The gas port can be on the left or right. The unused opening is
sealed off by a sealing screw, into which a gas pressure testing
nipple (3) is screwed.
The final electrode support ring (10) is fastened on the end of the
gas tube (9).
The flame rod (13) and the ignition electrode (12) are extended by
connecting rods (8). These connecting rods are guided through the
floor of the transformer housing and are supported around every
300 mm by intermediate support rings (7).
5.3
Ionisation flame monitor
Depending on the measured ionisation current (flame established)
of gas fired igniter, the ionisation flame monitor switches both
flame signal contacts. The yellow LED integrated into the
transformer part front panel is illuminated as long as there is a
flame signal.
5.3.1 Flame monitoring
The flame is monitored by the flame rod, which must immerse in
the direction of the flame. Alternating voltage is applied to this
flame rod. The burning flame creates an electrically conductive
connection to the igniter earth and at the same time acts as a
rectifier for the ionisation current. This direct current signal is
measured and amplified in the ionisation flame monitor. The
enforced flame signal activates the flame relay with one SPDT
contact (only series Z
DA…).
5.3.2 Safety time (flame failure detection time FFDT)
The safety time is the response time of the ionisation flame monitor
as the reaction to a failure of the flame signal (flame sensor
current) and as a result of that the clearing switch of the terminals
for the „flame-on“ signal. The standard safety time is ≤ 1 s (optional
3 or 5 s).
REMARK!
- In the case of a flame monitor exchange, steps
must be taken to ensure that the set safety times
of he devices are identical. The default safety
times is indicated on a type plate of the
transformer part front panel.
- To assess the permitted maximum safety time,
please observe the established safety norm for
which the operator is responsible.
- The default safety times may not be altered, as
this will lead to loss of type approval!