Control box LFL1
UV-detector
1
22
µ A
2
23
31
12. GENERAL INSTRUCTION
12.1 Flame monitoring and measurement of ionisation current
The burner is monitored according to the ionisation principle. Check the
ionisation current on start-up and on each service call.
The reason for a low ionisation current may be leaking currents, bad
connection to earth, dirt or a faulty position of the flame electrode in the
burner head. Sometimes also a faulty gas/air mixture may cause too
weak a ionisation current.
The ionisation current is measured by means of a microampere meter
(µA) connected in series with the flame electrode and the gas burner
control.
Connect the µA-meter, see figure. Min. required ionisation current
according to table. In practice this current must be considerably higher,
preferably more than 10 µA. All the gas burners are equipped with a
ionisation cable that can be slit which facilitates the connection of the
µA-device.
Gas control
Connection to terminal
Min. ionisation
in gas control
current required
LFL
24
10 µ A
Flame monitoring
12.2 UV-detector
This should not be exposed to temperatures exceeding 60°C. The
current passing through the UV-detector, when it is being illuminated,
should be at least 70 µ A for LFL1.. This current can be measured by
means of a moving coil instrument. Checks should only be made if a
fault is suspected.
The capacitor, which sould be placed between the terminals on the
moving coil instrument, must be of 100 µ F 10-25 V.
Flame monitoring
