6074
20
GB
Burner calibration
7.2.2
Steady state operation
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) closes, and the
burner passes from the 2nd to the 1st stage of operation.
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 control device TL opens, and solenoid valves
8)-16) close, the flame immediately goes out. The fan’s air
gate valve closes completely.
Systems 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) de-energizes, the fuel contained in
the cylinder 15), piston B, is discharged through the nozzle.
7.2.3
Firing failure
If the burner does not fire, it goes into lock-out within 5 s of the
opening of the 1st stage valve and 30 s after the closing of control
device TL.
The control box red pilot light will light up.
7.2.4
Undesired shutdown during operation
If the flame goes out during operation, the burner shuts down au-
tomatically within 1 second and automatically attempts to start
again by repeating the starting cycle.
7.2.5
Final checks
Darken the photoresistor and switch on the control
devices:
the burner should start and then lock-out about 5 s
after opening of the 1st stage operation valve.
Illuminate the photoresistor and switch on the control
devices:
the burner should start and then go into lock-out
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 ÷ 28 s,
sparking for about 5 s, burner goes into lock-out.
Switch off control device TL followed by control device
TS while the burner is operating:
the burner should stop.
