Safety Devices - Kärcher HDC 20/8 Manual

Water inlet
The water flows back from the swimmer
tank to the suction side of the pump. The
water level in the swimmer tank is kept con-
stant by the swimmer valve. In case of fail-
ure of the swimmer valve, the water exits
via the overflow. If the water supply is dis-
turbed, the lack of water fuse will send an
error message to the controls.
Pumps
The electric engine will drive the crankshaft
pump. The pump transports the water un-
der high pressure to the pressure side.
High pressure side
The high-pressure water reaches the high-
pressure output via the overflow valve and
the pressure sensor. After that, there will be
the high-pressure network of the operator.
Pressure regulation
Remaining water will be routed back to the
suction side of the pump by the overflow
valve. If all consumer loads have been
switched off, the overflow valve will switch
to circulation. If the pressure at the output
exceeds the maximum operating pressure
at the output, the safety valve will open.
Controls
– The appliance will be switched to
READY mode by activating the release
switch. The indicator lamp for opera-
tional readiness lights up. If the pres-
sure in the systems sinks below the de-
termined switch-on point due to the
opening of a hand spray gun, the high-
pressure pump will be switched on.
– If the flow switch in the high-pressure
line trips after closing all hand spray
guns while the pump is running, the
pump is switched off again with a delay
of 10 seconds (HDC 20/8) or 30 sec-
onds (HDC 20/16).
– If the system is ready and the high-
pressure is not turned on, a timer is
started, which will reset the readiness of
the unit after 6 hours. The operation
readiness indicator lamp goes off.
3
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EN

Safety Devices

Safety devices serve for the protection of
the user and must not be put out of opera-
tion or bypassed with respect to their func-
tion.
Safety mechanism against lack of
water in swimmer tank
The safety mechanism against lack of wa-
ter prevents the high pressure pump from
being switched on when there is no water.
Temperature sensor
The temperature sensor switches off the
appliance as soon as the water tempera-
ture is too high.
Winding protection contact
The winding protection contact in the motor
winding of the pump drive switches off the
engine when there is a thermal overload.
Safety valve
– The safety valve opens when the over-
flow valve is defective.
– The safety valve is set by the manufac-
turer and sealed. Setting only by cus-
tomer service.
Overflow valve with flow switch
– If the hand spray gun is closed, the
overflow valve opens and the entire wa-
ter volume will flow back to the pump
suction side.
– If the hand spray gun is closed, the
pump is switched off via the flow switch
after a stopping time of 10 seconds
(HDC 20/8) or 30 seconds (HDC 20/16).
Pressure sensor
If the hand spray gun is opened again, the
pressure switch switches on the pump via
the pressure sensor.
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