Xo 4, Troubleshooting Manual, Page: 27 / 88

XO 4 & XO FLEX TROUBLE SHOOTING GUIDE
Version 3.30 27
“FLOWMETER”, AP-921:
Purpose:
The flowmeter is equipped of a high viscosity monolithic silicon pressure sensor measuring the current
amount of water passing through the nozzle. The differential piezo-resistive transducer transmits the data
to the microprocessor on the “Bridge PCB AN-368”.
The proportional valve opens completely if the flow meter does not send signals to the microprocessor.
Max water quantity.
The flow meter is very sensitive to the reversal of the water passage which may damage it, the water
must flow in the direction indicated in the diagram below. A black dot for this purpose is located on the
green tube indicating the return of water.
Failure description Reason Solution
Water arrives on the syringe
but not distributed on the
other instruments
The nozzle on the flow meter is
obstructed. Remove and clean the nozzle on
the flow meter.
Follow the instructions in the
manual
“YB-910 Instruction cleaning
Flow meter”.
Check if the proportional valve
AN-903 is working properly (not
obstructed)
It is not possible to adjust
the flow rate on the
instruments.
The microprocessor does not
receive a signal from the flow
meter and the proportional valve
is open at maximum. Check that the CA-021 cable is
correctly mounted. Change it if
defective.
Check that the flow meter is
working properly.
Point of measurement:
In case the water flow cannot be regulated (always 100%)
- Either the flow meter is defective
- Or the microprocessor doesn't convert the signals from the flowmeter
J7 Pin 4 (Analog Flow Output)
J7 Pin 5 (GND)
Stand-by = 321mV
When activating an instrument
(But syringe) J3 Pin 5 (Analog MUX Out)
J4 Pin 3 (GND)
Stand-by = 297mV
When activating an instrument
(But syringe)
100 ml = 2,49 V
50 ml = 1,20 V
35 ml = 0,80 V 100 ml = 1,70 V
50 ml = 0,90 V
10 ml = 0,34 V
If no variation, change the
“Flowmeter AP-921” If no variation, change the
“Bridge PCB AN-368”.