07/2009 - Art. Nr. 13 022 182A
15
Commissioning
Setting the gas pressure switch/air pressure switch
Function check
Gas pressure switch setting
• To set the switch-off pressure: remove
the cover from the gas pressure
switch.
• Install a gas pressure
pa
measuring
instrument.
• Start the burner.
• Lower the pressure upstream of the
gas train by gradually closing the
manual valve, until
- gas pressure
pa
downstream of the
train drops to 70% of its initial value
- the stability of the flame reduces
visibly
- the CO level rises
- or the flame signal weakens
significantly
• Turn the dial clockwise until the gas
pressure switch shuts down the
burner.
• Continue turning the dial clockwise to
set the gas pressure switch to 10%
above the shutdown value determined
above.
The gas pressure switch adjustment
value must be higher than the air
pressure, but lower than the gas
pressure downstream of the gas valve.
Checking the switch-off pressure
• Open the manual shut-off valve
• Start the burner
• Close the manual shut-off valve
The gas failure procedure should start
without the burner control unit locking.
Function 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.
- Starting attempt with gas valve closed:
the control and safety unit must lock at
the end of the safety time.
- Starting with the air pressure switch
closed:
after an 8-second test period, the
burner switches to malfunction mode.
- Starting attempt with air pressure
switch open:
after a 60-second waiting period, the
control and safety unit locks.
- Starting attempt with brief opening of
the air pressure switch during pre-
ventilation:
the control and safety unit restarts the
pre-ventilation programme (air
pressure detected again within 60
seconds); otherwise lockout occurs.
Setting the air pressure switch
To adjust the switch-off pressure:
• Commission the burner.
• Increase the shut-off point by turning
the adjustment scale clockwise until
the burner switches off.
• Set the shut-off point to approximately
15% below the triggering pressure
that is now set.
en
Summary of Contents for NC12 B117
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