17
BURNER OPERATION
BURNER STARTING
(A)
•
0s:
Remote control device TL closes.
The control box starting cycle begins.
•
2s:
Fan motor starts.
Servomotor starts: it rotates to right, un-
til contact is made on cam St1 (orange
lever). The air gate valve moves to MIN
output position (stage 1).
•
7s:
Pre-purge stage with air delivery at 1st
stage output.
Duration 85 seconds.
•
92s:
Ignition electrode strikes a spark.
Safety valve VS and adjustment valve
VR, 1st stage (fast opening) open. The
flame is ignited at a low output level
(point A).
Delivery is then progressively in-
creased, with the valve opening slowly
up to MIN output, 1st stage, point B.
•
94s:
The spark goes out.
•
102s: If remote control device TR is closed or
if it has been replaced by a jumper, the
servomotor will continue to turn until
cam St2 (red lever) operates. The air
gate valve moves to the MAX output po-
sition, (stage 2). Before reaching the
closed position, the cam with the black
lever controls the opening of the adjust-
ment valve VR, 2nd stage, point K.
Output gradually increases from stage
1 to 2, section C-D.
The control box starting cycle ends.
STEADY STATE OPERATION (A)
System equipped with one control device TR.
Once the starting cycle has come to an end, con-
trol of the servomotor passes on to the remote
control device TR that controls boiler tempera-
ture or pressure, point C.
(The control box will continue, however, to mon-
itor flame presence and the correct position of
the air pressure switch).
•
When the temperature or the pressure increas-
es until the control device TR opens, the burner
passes from the 2nd to the 1st stage of opera-
tion, section E - F.
•
When the temperature or pressure decreases
until the control device TR closes, the burner
passes from the 1st to the 2nd stage of opera-
tion, and so on.
•
The burner stops when the demand for heat is
less than the amount of heat delivered by the
burner in the 1st stage, section H-I. Remote
control device TL now opens, the servomotor
returns toward the 0¯ position, limited in this
movement by cam St0 (blue lever). The air
gate valve closes completely to reduce heat
losses to a minimum.
Systems not equipped with remote control
device TR
(jumper wire installed)
The burner is fired as described in the case
above. If the temperature or pressure increase
until remote control device TL opens, the burner
shuts down (Section A-A in the diagram).
FIRING FAILURE (B)
If the burner does not fire, it goes into lock-out
within 3 s of the opening of the gas solenoid
valve and 43 s after the closing of remote control
device TL. The control box pilot light will light up.
BURNER FLAME GOES OUT DURING OPER-
ATION
If the flame should accidentally go out during op-
eration, the burner will lock out within 1s.
NO FIRING
NORMAL FIRING
(n° = seconds from instant 0)
(A)
20145717
20145814
(B)
Summary of Contents for GAS 9/2
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