6423
26
GB
Start-up, calibration and operation of the burner
8.4
Steady state operation
8.4.1
System equipped with one control device TR
Once the starting cycle has come to an end, the command of the
2nd stage solenoid valve passes on to the control device TR that
controls boiler temperature or pressure.
•
When the temperature or the pressure increases until the
control device TR opens, solenoid valve 11)(Fig. 29) closes,
and the burner passes from the 2nd to the 1st stage of oper-
ation.
•
When the temperature or pressure decreases until the con-
trol device TR closes, solenoid valve 11) opens, and the
burner passes from the 1st to the 2nd stage of operation, 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. In this
case, the remote control device TL opens, solenoid valve 8)
- 16)(Fig. 29) closes, the flame immediately goes out. The
fan's air damper valve closes completely.
8.4.2
System not equipped with control device TR
(jumper wire installed)
The burner is fired as described in the case above. If the temper-
ature or pressure increase until control device TL opens, the
burner shuts down (Section A-A in the diagram).
When the solenoid valve 11)(Fig. 29) de-energizes, the piston
12)(Fig. 29) closes the passage to the 2nd stage nozzle and the
fuel contained in the cylinder 15), piston B, is discharged into the
return piping 7).
8.5
Final checks
Obscure the photocell and switch on the control devices: the
burner should start and then lockout about 5s after opening of the
1st nozzle operation valve.
Illuminate the photocell and switch on the control devices: the
burner should start and then go into lockout after about 10 s.
Obscure the photocell while the burner is in 2nd stage operation,
the following must occur in sequence: flame extinguished within
1 s, pre-purging for about 20 s, sparking for about 5 s, burner
goes into lockout.
Switch off control device TL followed by control device TS while
the burner is operating: the burner should stop.
Fig. 29
D8632
