3
3. Lock out and reset
The unit can be reset or brought into lock out mode in two
different ways:
Internal
In the lock out case the unit can be reset by pushing the built-
in button meaning a new start-up cycle is performed.
External
Instead of using the built-in lock out button the same
function can be achieved by using an external button which
connects terminal 9 with A (see also circuit and block
diagram).
If the pushputton (internal or external) is pressed during
normal operation or during the start sequence for more then
3 sec. and afterwards released, the control box will perform
a shutdown.
Please note
The unit can only be brought to lockout mode or
be reseted if power is applied to the unit.
4. Low-voltage protection
at 220 / 240V (110 / 120V) nominal voltage
The mains voltage has to be more than 187 V
eff
(94 V
eff
) in
order to allow the unit to perform a start-up.
The mains voltage is not only monitored in the start-up
phase but also permanently during operation. If the voltage
drops below < 160 V
eff
(80 V
eff
) during start-up or run time the
control box proceed to safety shut-down and goes into a
waiting status. If the voltage rises again, the control box
performs automatically a start-up as soon as the mains
voltage is > 187 V
eff
(94 V
eff
).
5. Safety
The design and control sequence of the DMG 970 controls
will comply with the currently applicable standards and
regulations (see also TECHNICAL DATA).
6. Burner with an air damper motor
The position of the air damper during pre-purge
has to be assured by suitable actions
(EN 676, 4.4.1.2).
7. Mounting and electrical wiring
Wiring base:
– 3 earth terminals with additional terminal for burner
earthing
– 3 neutral terminals with internal permanent connection to
neutral terminal 8
– 2 independant spare terminals (S1 and S2)
– extra terminals A, B and C are standard (wiring base S98
12-pin)
– 2 slide-in plates and 2 easy knock out holes plus 2 knock
out holes in the base bottom faciliate the base wiring
Please note
To assist trouble-free operation the main neutral
connection terminal 8 in the wiring base must be
fully tightened. The terminal screws are already in
the undone position. To connect a wire to the
terminal, the screw only needs to be fastened.
General: The control box and detector probes should not be
subjected to excessive vibration.
DMG 973