HOW TO FIND THE CAUSES OF IMPROPER OPERATION OF TWO-STAGE GAS BUR-
NERS AND HOW TO RECTIFY THEM
PROBLEM
T h e
a p p a r a t u s
g o e s
i n t o
" l o c k - o u t "
w i t h
the flame (red light on). Malfunc-
tioning is due to the flame control
device.
The apparatus goes into "lock-
out", gas flows out, but there
is no flame (red light on).
Fault restricted to ignition
circuit.
T h e a p p a r a t u s g o e s i n t o
" l o c k - o u t " , g a s f l o w s
out, but there is no flame
(red light on)
POSSIBLE CAUSE
1) Disturbance to ionization current from the
ignition transformer.
2) Inefficient flame sensor (ionization
probe).
3) Incorrect flame sensor (ionization probe)
position.
4) Ionization probe or relative earth cable.
5) Electrical connection cut-off by flame
sensor.
6) Inefficient draught or fumes passage
blocked.
7) Flame disk or combustion heads dirty or
worn.
8) Equipment fault.
9) No ionization.
1) Fault in ignition circuit
2) Ignition transformer cable discharges to
earth.
3) Ignition transformer cable disconnected.
4) Ignition transformer faulty.
5) The distance between electrode and
earth is incorrect.
6) Isolator dirty, so electrode discharges to
earth.
1) Air/gas ratio incorrect.
2) Gas pipe has not been properly bled of
air (in the case of first ignition).
3) The gas pressure is insufficient or exces-
sive.
4) Air flow between disk and head
too narrow.
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REMEDY
1) Invert the ignition transformer power supply
(230V side) and check using an analogue
micro-ammeter.
2) Replace flame sensor
3) Correct the position of the flame sensor, and
then check its efficiency by connecting the
analogue micro-ammeter.
4) Check visually and using the instrument.
5) Restore the connection.
6) Ensure that the boiler fumes passage and
chimney connection are free.
7) Visually check and replace, if necessary.
8) Replace.
9) If the "earth" of the equipment is not efficient,
the ionization current cannot be checked. Check
the efficiency of the "earth" at the terminal
concerned in the equipment and at the "earth"
connection of the electric system.
1) Check the ignition transformer power supply
(230V side) and high voltage circuit (electrode to
earth or isolator broken under locking terminal).
2) Replace.
3) Connect.
4) Replace.
5) Position at the correct distance
6) Clean or change the isolator and the electrode.
1) Correct the air/gas ratio (there is probably too
much air or very little gas)
2) Bleed the gas pipe again, taking great care.
3) Check the gas pressure value at the time of ig-
nition (use a water pressure gauge, if possible).
4) Adjust the disk/head opening.