Siemens LGA41.153A27, Manual

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Building Technologies Division CC1N7418en
21.06.2016
Electrical connection of ionization probe
It is important to achieve practically disturbance- and loss-free signal transmission:

Never run the detector cable together with other cables
– Line capacitance reduces the magnitude of the flame signal
– Use a separate cable

Observe the permissible length of the detector cable (refer to «Technical data»)

The ionization probe and the ignition electrode are not protected against electric
shock hazard

Locate the ignition electrode and the ionization probe such that the ignition spark
cannot arc over to the ionization probe (risk of electrical overloads) and that it
cannot adversely affect the supervision of ionization

With ionization current supervision, the cable length for flame detection must not
exceed 20 m

Insulation resistance
- Must be a minimum of 50 M

between ionization probe and ground even after a
large number of operating hours
- Prerequisite for this is not only high quality heat-resistant insulation of the
electrode cable, but also of the ionization probe itself (ceramic holder!)
– Soiled detector holders reduce the insulation resistance, thus supporting
creepage currents

The burner (as the counter-electrode) must be correctly earthed, or else no
ionization current will flow

Since the burner bars form the earthed counter-electrode, the burner must be
adjusted so that the flame is hot and stable and in firm contact with the burner bars.
With pulsating flames or yellow-burning flames resulting from lack of air, a very low
or even no ionization current is generated so that the burner enters malfunction
Commissioning notes
When commissioning the plant or when doing maintenance work, make the following
safety checks:
Safety check to be carried out Anticipated response
a) Burner startup with no flame signal; for that purpose, open the
connection between burner control and ionization probe prior
to burner startup and maintain that status
Lockout at the end of «TSA»
b) Burner operation with simulated loss of flame during
operation; for that purpose, open the connection between
burner control and ionization probe during burner operation
and maintain that status
Restart, followed by lockout at the end of «TSA»
c) No air pressure signal during «t1» (only with LGA52... /
LGA63... with auxiliary fan)
No startup
d) Air pressure failure during operation (only with LGA52... /
LGA63... with auxiliary fan)
Shutdown