Electrical Connection Of Flame Detectors - Siemens LME7 Series Basic Documentation

Building Technologies
HVAC Products
1.4

Electrical connection of flame detectors

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 detector cable lengths (refer to «Technical Data»)
•
The mains-powered ionization probe is not protected against electric shock hazard.
Protection against accidental contact must be ensured
•
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 can-
not adversely affect the supervision of ionization
•
Insulation resistance
– Must be a minimum of 50 MΩ between ionization probe and ground
– Soiled detector holders reduce the isolation resistance, thus supporting
creepage currents
•
Earth the burner in compliance with the relevant regulations; earthing the boiler
alone does not suffice
Basic Documentation LME7...
1 Safety notes
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CC1P7105en
13.10.2009