92
Function
The drain valve uses the water pressure in the
cold-water inlet to close the valve. A feed hose
is connected between the water inlet and the
control valve.
When the control valve operates (drain valve
should be closed), the control valve opens the
water pressure onto the feed hose, which is con
-
nected to the lower part of the drain valve. When
the lower part is filled with water, the lower part
diaphragm pushes up the piston. The piston lifts
the pressure plate against the drain valve rubber
diaphragm, which in turn forms a seal against
the outer drum, effectively closing the valve.
When the drain valve should be opened, the
control valve changes position to allow the water
pressure to the lower part of the drain valve to
close, instead opening the return hose to the
drain. The pressure plate recoil springs pull the
pressure plate back, upon which the piston is
pressed back into the cylinder. The water from
the lower part is fed through the feed hose and
the control valve to the drain.
2
Drain valve
3359
8
1
2
3
11
10
9
6
5
4
7
2
12
101772
1.
Feed hose
2. Control valve
3. Feed hose
4. Return hose
5. Upper part
6. Rubber diaphragm
with drain connection
7. Pressure plate
8. Recoil springs
9. Cylinder
10. Piston
11. Diaphragm
12. Lower part
Principal
diagram
