18
MEASURES AND CHECKS BEFORE START UP
2-Stage or modulating burners
172 205 34-1 12-01
MEASURES AND CHECKS BEFORE START-UP
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 fi g.).
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.
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 fl ame
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 fi nished.
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.
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 fi g. 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.
Gas train
Multibloc
Summary of Contents for BG 550 LN
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