26
Bentone BG550/650
General
Multibloc
Gas train
5. Measures and checks
before start-up
5.1
2-Stage or modulating burners
General rules
Care should be taken by the installer to ensure that
no electrical cables or fuel/gas pipes are trapped or
damaged during installation or service/maintenance.
Inner assembly
Ensure that the ignition and ionisation electrodes are
correctly adjusted. The sketch (see separate page)
shows the correct measurements.
Gas quality
Ensure that the burner head is meant for the gas quality
to be used (see ig.).
Venting
The gas line is vented by loosening the screw on the test
nipple for the inlet pressure. Connect a plastic hose and
conduct the gas into the open air,
After having vented
the gas line tighten the screw again.
Leakage control
When making a leakage control of the gas supply
system, the solenoid valve should be closed. Connect
a pressure gauge to the test nipple Pa, see ig. The
test pressure in the system should be 1,5x max. inlet
pressure or min. 150 mbar. If any leakage, locate the
source by means of soapy water or a leak location spray.
After tightening repeat the test.
Electric function test:
Ensure that phase and neutral are not reversed. The
gas shut-off cock should be closed.To prevent the gas
pressure switch from locking out, it should be linked
temporarily.
After the main switch has been switched on and the
thermostats have been adjusted, the pre-purging period
begins (30-35sec.). At the end of this period the pre-
ignition period starts (0,5-2,5 sec. depending on the
design of the gas control). The gas valve is energized
and opens and lame is established. At the end of the
safety time (2-3 sec.) the gas control locks out. The
solenoid valve and the motor will be ”dead”. Remove
the link from the gas pressure switch after the test is
inished.
Note on 2-stage and modulating burners that during the
pre-purging period the damper opens to the set value
for air on stage 2 and just before the end of the pre-
purging period it goes down to the air setting for stage 1.
On some burners under 350kW the pre-purging mainly
takes place with the air damper set for stage 1.
NOTE! Applies only to gas burner control
LFL1...
When using LPG (Propane) the burner should be
connected for post-purging. Move the connection on
terminal 6 to terminal 7 in the base of LFL1.
