01/2009 - Art. Nr. 4200 1016 3900A
30
Air pressure switch adjustment
Factory setting: 1.0 mbar
The switching point must be tested and
reset during adjustment.
• Install the pressure measuring device,
for this install a T-piece in the pressure
tube.
• Switch on the burner.
• Adjust the switching point
approximately 15 % below the
triggering pressure that is now set.
Start up
Air pressure switch adjustment
Setting the gas pressostat
Operating check
Setting the gas pressostat
• To set the shut-off pressure: Remove
the cover of the gas pressostat.
• Connect a device for measuring gas
pressure
pa
.
• Start the burner.
• Reduce the gas pressure upstream of
the train by closing the manual shut-
off valve until either:
- Gas pressure
pa
downstream of the
train reduces to 70 %
- Flame stability noticeably
decreases
- The CO value increases
- The flame signal worsens
considerably
• Turn the dial clockwise until the gas
pressostat shuts down the burner.
• Turn it clockwise again to set the gas
pressostat 10 % above the
predetermined shutdown value.
The gas pressostat adjustment value
must be higher than the blower pressure
but lower than the gas pressure
downstream of the gas valve.
Check the switch-off point:
• Open the manual shut-off valve
• Burner start
• Close the manual shut-off valve
The gas shortage program should start
without the burner control unit triggering
a safety shutdown.
Operating check
Flame monitoring must be checked for
safety as part of initial commissioning
and also after servicing or if the system
has been out of operation for any
significant period of time.
- Start attempt with closed gas valve:
The automatic combustion control unit
must switch to gas shortage or
malfunction after the end of the safety
period.
- Start-up with air pressure switch
closed:
Burner switches to malfunction after a
test time of 8 sec.
- Start-up attempt with air pressure
switch open:
Automatic firing device switches to
malfunction after a wait time of 60 sec.
- Start-up attempt with briefly-open air
pressure switch during preventilation:
Automatic firing device starts the
preventilation program again if air
pressure builds up again within 60
seconds, otherwise a safety shutdown
is triggered.
