The RO will not start when the start
button is pressed.
“SYSTEM ON” is displayed on line 4 of
the Main Menu.
The product tank is full in Tank mode.
When the product tank is full the “Level”
LED is on and the RO will not run until the
level drops below the switch.
The level switch is set as closed when
product tank is full.
The tank level switch must be installed
as open when the tank is full.
AL250-V2 is in pretreatment interlock.
If the pretreatment interlock input is OFF
then the AL250-V2 will not start. The
pretreatment interlock LED will be ON.
Controller is in Stand-By Mode and
system is between auto flush cycles.
Review line 2 of the Main Menu for a
system MODE message.
Motor overload.
Check the high pressure pump for an
overload relay trip.
Display does not respond to keypad
entries.
Wrong screen on display.
Some keypad entries only function on
certain screens (i.e., Arrow keys do not
function on all displays).
Damaged keypad.
Verify key operation by using Key Test in
the Diagnostic screens.
AL250-V2 will not change between TANK
mode and DIRECT mode.
Wrong screen.
To change between TANK mode and
DIRECT mode use the settings menu and
select settings screen #0. The operation
mode cannot be changed from the MODE
menu. The operation mode cannot be
changed will the RO is running.
Conductivity reading is higher than known
solution.
Conductivity cell not calibrated.
Re-calibrate conductivity channel using
instructions in AL250-V2 manual.
Temperature sensor damaged or loose
wire on temperature sensor.
Review the raw analog values in the
diagnostic screens. The RTD values
must be less than 4095.
Check the resistance across the red and
green wires of BOTH sensors. The
acceptable range is 1000 – 1187 Ohms.
Air bubbles in sensing area.
Carefully loosen the compression ring
until a small stream drips from sensor
connection. DO NOT LOOSEN MORE
THAN 3 TURNS. Review the conductivity
reading while the sensor fitting drips. A
correct reading indicates air bubble
interference.
Fouled sensor.
Remove the sensor and inspect for scale
or foulant build up.
Damaged conductivity sensor.
Swap the permeate and feed sensor. If
the problem follows the sensor then
replace the faulty sensor. Make sure that
the
temperature
connections
are
swapped also.
5-2
