Service
Manual PageEdition
Type
1
2
3
6
7
8
9
1
38. Drain valve 51
38
G115
4
5
Description
The drain valve utilises the water pressure in the
cold water inlet to close the valve. A hose (1)
connects the water inlet and the control valve (2).
When the control valve is activated, it opens and
allows water to pass through the supply main (3)
which is connected to the drain valve. The water
pushes up a rubber diaphragm (4) and a piston (5)
by means of a pressure plate (6) which closes the
rubber diaphragm (7) on the valve.
When the control valve shuts off the water pressure
leading to the drain valve, the springs (8) pull back
the piston. The return water passes through the
control valve to the drain via the return hose and is
drained (9).
Fault tracing

Drain valve does not close

Check that:
there is voltage supply to the control valve (2).
hoses and control valve are not blocked. This is
done by disconnecting the supply main (3) to the
drain valve and activating the control valve.
the rubber diaphragm (4) is ok.
the piston (5) is not jammed.

Drain valve does not open

Check that:
the return hose (9) is not blocked.
the piston (5) is not jammed.
Fig.
1
9002