55
Start-up
Oil Pressure Switch
Air Pressure Switch
Oil pressure switch
Oil pressure switches are provided to
burners for monitoring the oil pressure.
Depending on the burner design, the oil
pressure switches can be installed eit-
her in the return line only or in both the
return line and feed line. The cut-out
pressure will be selected depending on
the burner system data (ring line pres-
sure, oil nozzle, etc.).
Oil pressure damper
An oil pressure damper or a capillary
pipe may be installed in the connection
fitting (2) to make up for oil pressure
variations.
Operating pressure adjustment
For adjusting the operating pressure,
remove the setting know (1) by pulling it
upward and reinstall it again the other
way round. After the adjustment has
been completed make sure to install the
setting know in its original position
again.
Switching difference
The switching difference may be selec-
ted on the pressure switches within the
limits shown in the table. For the adjust-
ment, turn the threaded pin in the set
screw (3) for the switching point. One
turn will change the switching difference
by approx. 20 % of the total range of the
switching difference. The oil pressure
switch has a facility for attaching a seal.
1
2
3
Type
Setting
range
Switching
difference
Location
DSB 158 F...
0 - 25 bar
1,0...7,5 bar Return line acc. to EN 267; alterna-
tive if finer switch difference required
DSB 146 F...
0 - 10 bar
0,7... 4,0 bar Optional feed line and return line acc.
to EN 267; aggressive media
DSF 158 F...
0 - 25 bar
1,5... 8,0 bar Optional return line acc. to EN 267;
aggressive media, alternative if finer
switch difference required
DSF 152 F...
0 - 16 bar
1,2...3,5 bar Return line acc. to EN 267; alterna-
tive if finer switch difference required
Air pressure switch
The air pressure switch is provided for
monitoring the pressure of the combu-
stion air fan.
The pressure switch DL 50A has been
designed for switching on, off or over an
electric circuit in the case of changes of
the actual pressure levels from the set-
point setting. The pressure switch DL
50A can be used as overpressure,
vacuum or differential pressure monitor
for air and non-aggressive gases but
not for gases according to DVGW
Worksheet G 260/l.
Determining the differential pre-
flushing pressure and adjusting the
differential pressure switch
• Burner in the pre-aeration phase.
• Measure pressure on test
connection (2).
• Measure vacuum on test
connection (3).
• Add the measured pressures.
• Set the scale to 90% of the calculated
value.
Certification
The pressure switch has been tested in
accordance with DIN 3398 Part 2 and is
registered by CE/DIN-DVGW. It has
been registered in other important gas
consumption countries.
Switch function test
Test buttons are provided to check the
switch functions for proper operation
(with safety cut-out and interlock). The
burner is normally run in partial-load
condition when testing the safety
functions. On pressing button (4) the
vacuum will be removed which causes
the differential pressure to drop below
the required level. If it is necessary to
test the pressure switch functions under
full-load conditions this may be done by
pressing button (1).
