Electrolux WE170P, Service Manual

Page: 47 / 85

47
10.17 Solenoid valves
10.17.1 General characteristics
SOLENOID VALVE
HOT WATER
SOLENOID VALVE
THREE WAYS
The solenoids opens for water into the detergent dispenser and is controlled electrically by the main circuit
board via Triac. The level of water in the drum is controlled by the water level sensor.
1. Water inlet
2. Solenoid valve body
3. Filter
4. Flow
reducer
5. Coil
6. Spring
7. Moving
core
8. Rubber
9. Membrane
10. Water outlet
10.17.1.1 Operating principle
When idle, the core, pushed by a spring, keeps the central hole of the membrane closed and so the latter
hermetically seals access to the water inlet duct.
When the coil is powered, the core is attracted, releasing the central hole of the membrane. Consequently
the valve opens.
10.17.1.2 Mechanical jamming of the solenoid valve
The solenoid valve may jam open without being actuated (which will cause flooding if the water level sensor
controlling the water level does not trip). If this occurs, the electronic control system (which continuously
monitors the flow sensor) will lock the door, start the drain pump and display an ALARM simultaneously.
10.17.1.3 Low water pressure
If the flow sensor does not generate a signal during the water fill phases, even though power is being
supplied to the solenoid valve, the cause of this condition may be a closed water tap or clogged filter on the
solenoid valve (with ensuing low water pressure). If this occurs, only a WARNING will be displayed and the
cycle will continue for five minutes, after which time an ALARM will be signalled.