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Pressure switch
Air pressure switch
N6... N9
EKEVO 6... 7
26
Air pressure switch
The air pressure switch is provided for
monitoring the pressure of the
combustion air fan. Pressure switch
LGW... is suitable for switching an
electrical circuit or for switching it on or off
if the actual pressure values are
changing in relation to the setpoint. The
pressure switch LGW... can be used as
an overpressure, vacuum or differential
pressure switch for air and non-
aggressive gases but not for gases
according to DVGW Worksheet G 260/l.
Certification
The pressure switch has been tested in
accordance with EN1854 and is CE/DIN-
DVGW-registered. It has been registered
Determining the differential
pre-flushing pressure and adjusting
the differential pressure switch
Setting for operation without
frequency converter
• Burner in the preventilation phase.
• Measure the pressure at the test
connection (2).
• Measure the vacuum at the test
connection (3) or directly at the air box
(item 4)
• Add the measured pressures.
• Set the scale to 90% of the calculated
value.
Alternative procedure:
• Pre-set pressure switch to maximum
value (2.5 mbar)
• Burner at max. power
• Slowly increase the differential
pressure setting at the pressure
switch until the burner shuts off
• Set 90% of the measured shut-off
pressure on the scale
Setting for operation with frequency
converter
• Burner with min. calorific power. *
• Measure the pressure at the test
connection (2).
• Measure the vacuum at the test
connection (3) or directly at the air box
(item 4)
• Add the measured pressures.
• Set the scale to 90% of the calculated
value.
EKEVO 8... 9
03/2016 - Art. Nr. 4200 1044 8002A
in other important gas consumption
countries.
N.B.(Gas and air pressure switches)
The pressure switches must be set in
accordance with the specifications.
Furthermore, each time they are set, a
function test must be carried out. Non-
compliance could result in personal
injury or damage to property!
Once the pressure switches have
been set, they must be protected to
prevent settings from being altered.
For example, this can be done by
placing a spot of varnish on at least
one of the screws on the equipment's
protective cover.
Alternative procedure:
• Pre-set pressure switch to maximum
value (2.5 mbar)
• Burner with min. calorific power. *
• Slowly increase the differential
pressure setting at the pressure
switch until the burner shuts off
• Set 90% of the measured shut-off
pressure on the scale
* The basic principle is that for a
minimum load the motor frequency is
set to the minimum and that the motor
frequency setting increases with the
increase in the load.
Important note:
After the adjustment procedure, it is
necessary to check that the air pressure
switch is operating correctly across the
entire power range. It may then be
necessary to modify the air pressure
switch setting, even if the setting and
operation are correct. In this case, the
switching pressure can be reduced in
stages (5% max.). At each stage, it must
be ensured that the chosen setting is
sufficient.
Switch function test
• The switch functions can be tested
using the test button (with safety shut-
off and locking). If the pressure switch
functionality check is required with full
load, press button (item 1). To test the
burner in partial or full load, the
vacuum line must be detached from
the pressure switch measuring point
(item 3 or 4). This removes the
vacuum and the required differential
pressure is not reached, and the
burner goes into fault.
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