Xo 4, Troubleshooting Manual

Page: 62 / 88

XO 4 & XO FLEX TROUBLE SHOOTING GUIDE
Version 3.30 62
BACKFLOW PREVENTION
The backflow Prevention System is designed to avoid any risk of water contamination after mixing.
The system is maintained the container under pressure after filling. The system consists of a mixing cup,
a sensor, a backflow prevention tank equipped with non-return valve, air and water inlet pipes and two
solenoid valves.
Failure description Reason Solution
No water in the container. The check valve is defective. Unscrew and remove the mixing
cup from above the container to
access the check valve. Unscrew
the plug and clean or replace it
(UG-809).
Important: It is very important that the check
valve is mounted correctly to
avoid any backflow into the
bucket when the container is
pressurized.
Sensor pins are not properly
placed in the mixing cup or are
defective Refer to chapter "Liquid sensor
PCB” AP-869" on page 54
The water supply valve V27 is
defective Verify that the connectors are
properly inserted.
Measure the voltage at the coil
connectors 24VDC.
Measure the coil resistance
(≈100Ω).
Disassemble and clean the valve
at the piston.
Change the plunger seat gasket
(MR-150).
The 3-way air supply valve V30
for pressurized air is defective Check the voltage 24VDC on the
valve connectors.
Verify that the connectors are
properly inserted.
Measure the coil resistance
(≈100Ω).
Disassemble and clean the valve
at the piston.
Change the plunger seat gasket
(MR-150).
replace if faulty, AO-777
The main water valve V10 (Ø3, 2-
way, 1/8RG) is defective. Refer to the chapter
WATER/AIR XO4 and XO Flex
Page 52 for explanation.
Verify that the connectors are
properly inserted.
Measure the voltage at the coil
connectors 24VDC
Measure the coil resistance
(≈100Ω).
Change if defective UC-584.
Disassemble and clean the valve
at the piston.
Change the plunger seat gasket
(MR-150).