23
20035784
Electrical system
Key (Fig. 24 - Fig. 25)
I1 - Burner manual stop switch
MA - Star-delta starter terminal strip
MB - Burner terminal strip
PS - Reset push-button
S - Remote lock-out signal
TL - Load limit remote control system:
shut down the burner when the boiler temperature or
pressure reaches the maximum preset value
TS - Safety load control system:
operateds when TL is faulty
T2 - 2
nd
stage load control system
T3 - 3
rd
stage load control system
6.5 Calibration of thermal relay
This is required to avoid motor burn-out in the event of a signifi-
cant increase in power absorption caused by a missing phase.
If the motor is star-powered, 400 V, the cursor should be posi-
tioned to “MIN”.
If it is delta-powered, 230 V, the cursor should be positioned to
“MAX”.
If the scale of the thermal relay does not include rated motor ab-
sorption at 400 V, protection is still ensured.
NOTE
In systems where the run of wiring connecting the thermostat ex-
ceeds 20 metres in length, or in places where the burner is sub-
ject to particularly disturbing electromagnetic interference (over
10 v/m), you must insert the relay-interface kit item number
3010386.
Fig. 25
P 300-450 T/G
Star-delta motor starting
D2570
Cables cross-section
P 300 T/G P 450 T/G
230 V 400 V 230 V 400 V
FA gG/gL50406350
L
mm
2
64106
E
mm
2
42,56 4
Check the lock-out by darkening the photo-cell af-
ter removal of the cover.
ATTENTION: HIGH VOLTAGE
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