Burner Operation; Burner Start-Up; Steady State Operation; Ignition Failure - Riello RS 34 MZ Installation, Use And Maintenance Instructions

5.8

Burner operation

5.8.1

Burner start-up

Remote control TL closes.
Servomotor starts: it rotates during opening up to the
angle set on cam St1.
After about 3s:
0 s The control box starting cycle begins.
2 s Fan motor starts.
3 s Servomotor starts: it rotates during opening until contact
on cam St2 is tripped.
The air damper is positioned to 2nd stage output.
Pre-purge stage with air delivery at 2nd stage output.
Duration 25 seconds.
28 s Servomotor starts: it rotates during closing up to the
angle set on cam St1.
43 s The air damper and the gas butterfly are positioned to
1st stage output.
Ignition electrode strikes a spark.
Safety valve VS and adjustment valve VR (rapid
opening) open. The flame is ignited at a low output level,
point A. Output is then progressively increased, with the
valve opening slowly up to 1st stage output, point B.
45 s The spark goes out.
53 s If remote control device TR is closed or if it has been
replaced by a bridge, the servomotor will continue to turn
until the cam St2 come into operation, setting the air
damper and the gas butterfly valve to the 2nd stage
operation position, section C-D.
The control box starting cycle ends.
The control box starting cycle ends. When heat demand (TL) is
satisfied, the post-purging phase (*20s) starts.
5.8.2

Steady state operation

System equipped with one remote control TR
Once the starting cycle has come to an end, control of the
servomotor passes on to the remote control TR that controls
boiler temperature or pressure, point D.
(The control box will continue, however, to monitor flame
presence and the correct position of the air pressure switch).
• When the temperature or the pressure increases until the
control device TR opens, the servomotor closes the gas
butterfly valve and the air damper and the burner passes from
the 2nd to the 1st stage of operation, section E-F.
• When the temperature or pressure decreases until the
control device TR closes, the servomotor opens the gas
butterfly valve and the air damper and the burner passes from
the 1st to the 2nd stage of operation.
The sequence repeats endlessly.
• The stopping of the burner occurs when the heat requirement
is lower than that supplied by the burner in the 1st stage, tract
G - H. The TL remote control opens, the servomotor returns
to angle 0° limited by cam St0.
The air damper closes completely to reduce heat losses to a
minimum.
Systems not equipped with TR (bridge installed)
The burner is fired as described in the case above. If the
temperature or pressure increase until control device TL opens,
the burner shuts down (Section A-A in the diagram).
20190369
Start-up, calibration and operation of the burner
2
VR
VS
3
2°
1°
0
2°
1°
0
LED
*
RMG
3
0 sec
* Off Yellow
For further details see page 33.
5.8.3

Ignition failure

If the burner does not fire, it goes into lockout within 3 s of the
opening of the gas solenoid valve and 49 s after the closing of
remote control TL. The control box red pilot light will light up.
Burner flame goes out during operation
If the flame should accidentally go out during operation, the
burner will lock out within 1s.
2
VR
VS
3
2°
1°
0
2°
1°
0
LED
*
RMG
3
*
0 sec
* Off Yellow
For further details see page 33.
28 GB
STANDARD IGNITION
(no. = seconds from instant 0)
A
43 45
28
E
D
B C F
A
53
46
A
Green Red
IGNITION FAILURE
*
43
45
46
28
*
46
Red
*
*
G
H
20190516
Fig. 34
20190517
Fig. 35