Dungs GW A4 - Page 2

2 … 6
44 ซ.บรมราชชนนี 70 ถ.บรมราชชนนี ศาลาธรรมสพน์ ทวีวัฒนา กทม. 10170.
website: https://www.add-furnace.com/ โทร: 02-888-3472
Line ID: @add11 e-mail: add028883472@gmail.com
Functional description
Single-acting pressure switch or pres-
sure limiter in pressure range.
The pressure switches and/or pres-
sure limiters work without using any
auxiliary power.
GW A4 pressure switch
The control unit responds to pressure.
If the set reference value is exceeded
or undershot, the circuit is switched
on, off or over.
ÜB A4, NB A4 pressure limiters
The control unit responds to pressure.
Interlock is performed when the set
reference value is exceeded or under-
shot.
The "Locked" switching state is indi-
cated by a glow lamp.
Restart is only possible by activating
the reset button on the setting wheel of
the pressure limiter after the operating
pressure is attained.
ÜB A4: Switches and locks when the
set pressure is exceeded.
NB A4: Switches and locks when the
set pressure is undershot.
Double pressure switch
GW A4 / GW A4
Combination of two GW A4 single pres-
sure switches flanged together. The
setting of the two reference values is
performed separately and independ-
ently. This permits a combination of
different reference value setting rang-
es. The same medium and pressure
are applied to the two control units.
Operating state
N
1
NC
2 NO
COM
3
NB A4 switching function
As pressure falls
2 NO opens, 1 NC closes
Glow lamp ON, locked.
p
N
1
NC
2 NO
COM
3
ÜB A4 switching function
As pressure rises
2 NO closes, 1 NC opens
Glow lamp ON, locked.
p
GW A4 switching function
As pressure rises:
1 NC opens, 2 NO closes
As pressure falls:
1 NC closes, 2 NO opens
2 NO
COM
3
1
NC
p
Lower switching
pressure
Upper switching
pressure
Setting tolerance
Pressure
at meter
Definition of switching difference p
The switching difference p is the
pressure difference between the up-
per and lower switching pressures
Switching difference p
Adjustment as
pressure falls
Rising
Falling