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Building Technologies
CC1N7106en
HVAC Products
20.02.2008
Electrical connection of flame detectors
It is important to achieve practically disturbance- and loss-free signal transmission:
•
Never run detector cables together with other cables
– Line capacitance reduces the magnitude of the flame signal
– Use a separate cable
•
Observe the permissible length of the detector cables (refer to «Technical data»)
•
The ionization probe is not protected against electric shock hazard
•
Locate the high-voltage ignition electrode and the ionization probe such that the igni-
tion spark cannot arc over to the ionization probe (risk of electrical overloads) and that
it cannot adversely affect the supervision of ionization
•
Insulation
resistance
– Must be a minimum of 50 M
Ω
between ionization probe and ground
– Soiled detector holders reduce the insulation resistance, thus supporting cree-
page currents
•
Earth the burner in compliance with the relevant regulations; earthing the boiler alone
does not suffice
Commissioning notes
When commissioning the plant for the first time or when doing maintenance work, make
the following safety checks:
Safety check to be carried
out
Expected response
Supply state (factory setting):
a)
Burner startup with previously
interrupted line to the flame
detector
Lockout at the end of «TSA»
→
Max. 3 repetitions
b)
Burner operation with simulated
loss of flame. For that purpose,
cut off the gas supply
•
Establishment of flame at the end of
«TSA»
→
Max. 3 repetitions
(can be parameterized)
→
Factory setting: Lockout
•
No establishment of flame at the end
of «TSA»
→
Lockout
c)
Burner operation with simulated
air pressure failure (not with
atmospheric burners)
Immediate lockout
After installation and commissioning, the parameterized values and settings must be
documented
by the person / heating engineer responsible for the plant. These data can
be printed out with the help of the ACS410 PC software, for example, or must be written
down. The documentation must be checked by the expert and then kept in a safe place.
On the OEM access level of the LME39…, it is possible to make parameter settings
that differ from application standards. When setting the parameters, it must be made
certain that the application will run safely in accordance with legal requirements.
Prior to commissioning, the following points must be checked:
•
The correct time parameter settings, especially the settings of the safety and pre-
purge times
•
The correct functioning of the flame detector in the event of loss of flame during
operation (including the response time); with extraneous light, during the prepurge
time and, when there is no establishment of flame, at the end of the safety time
•
Air
pressure
•
Safety loop (e.g. STB)
•
Minimum gas pressure (GP)
