F1 F2 F3 F4 F5 F6 F7 F8 F9
F
ee
d
F
lo
w
(
+)
F
ee
d
F
lo
w
(
-)
F
ee
d
F
lo
w
S
ig
na
l
P
er
m
/R
ej
ec
t F
lo
w
(
+)
P
er
m
/R
ej
ec
t (
-)
P
er
m
/R
ej
ec
t F
lo
w
S
ig
na
l
R
ec
yc
le
F
lo
w
(
+)
R
ec
yc
le
F
lo
w
(
-)
R
ec
yc
le
F
lo
w
S
ig
na
l
+
-
+
-
+
-
Discrete Inputs
All inputs should be dry contacts rated for 24 VAC
. Do not apply voltage to the
inputs.
Input voltage to the contacts is supplied by the AL250-V2.
Low Pressure Switch
: This is a dry contact that signals the system to shut down
if the pump suction pressure falls below the desired value. This is a
normally closed contact (when the system is shut down). When a
circuit is not complete between the two terminals, the system will
operate. If contact is made between the two terminals, the system will
shut down.
High Pressure Switch
: This is a dry contact that signals the system to shut
down if the pump discharge or membrane pressure exceeds the
desired value. This is a normally open contact. When an open circuit
condition exists between the two terminals, the system will operate. If
contact is made between the two terminals, the system will shut down.
Pretreatment Interlock:
This input is designed to be normally closed. If a
pretreatment interlock input is not being connected, a wire jumper must
be installed between the two terminals at Input 5. Since the input is
normally closed, multiple devices may be wired to this input in series.
Chemical Pump Failure*:
This is a dry contact that signals the failure of the
chemical injection system. This is a normally open contact. When an
open circuit condition exists between the two terminals, the system will
operate. If contact is made between the two terminals, the system will
shut down.
Tank Level Switches:
The AL250-V2 is designed to be used with one or two
tank level switches. Switches should be wired in the normally closed
position (the switch contacts close when the water level drops below
the switch). When using two switches, a low-level tank switch starts
the system (in Tank Feed mode) and a high-level switch stops the
system. When using one switch, the switch connected must be a high-
2-6
