Safety Devices - Kärcher HDI 38/12 Manual

Water inlet
Water supply without swimmer tank
The water is guided directly to the suction
side of the high pressure pump (if neces-
sary via the advance pressure pump).
Water supply with swimmer tank
– The water is guided from the swimmer
tank (could be via the advance pressure
pump) to the suction side of the pump.
The water level in the swimmer tank is
kept constant by the swimmer valve. In
case of failure of the swimmer valve,
the water exits via the overflow.
– The safety mechanism against lack of
water prevents the high pressure pump
from being switched on when there is
no water.
– The temperature sensor switches off
the appliance as soon as the water tem-
perature is too high.
High-pressure pump
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 switches (single and subse-
quent operation). 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 high pressure pump by
the overflow valve. If all extraction locations
are closed, the overflow valve will com-
pletely switch to backflow to the suction
side of the high pressure pump. If the pres-
sure at the output exceeds the maximum
operating pressure at the output, the safety
valve will open.
Advance pressure pump
– The advance pressure pump will build
up an advance pressure of 0.3 to 0.6
bar with a water supply temperature of
more than 60°C on the suction side of
the high pressure pump to prevent cav-
itation.
– The permissible water supply tempera-
ture is raised to 80°C.
Pressure switch for individual
operation
– The pressure switch is required for
hand lance operation with 1 high pres-
sure pump.
– The pressure switch is fitted to the vol-
ume control.
– The pressure switch turns on the high
pressure pumpe if the pressure falls be-
low the preset value.
Pressure switch for subsequent
operation
– The pressure switch is required for
hand lance operation of 2 or more high
pressure pumps.
– The pressure switch is fitted to the vol-
ume control in addition to the pressure
switch for single operation.
– The pressure switch turns on the sub-
sequent high pressure pump if the pres-
sure falls below the preset value.
Controls
The control of the system is taken over by
the control of the entire high-pressure
cleaning system.
The following single tasks must be fullfilled:
– Supply and control of the pump motor.
– Protects the motor against short circuits
and overloading.
– Switches off when the winding thermo-
stat is opened.
– Upgrade kit - star delta startup: Open
the pressure relief valve.
– Upgrade kit for steam stage: Open the
ball valve combination.
– Upgrade kit detergent supply 1: Open
the shut-off valve 1.
– Upgrade kit detergent supply 2: Open
the shut-off valve 2.
– Upgrade kit - volume control: Signal
monitoring of the flow switch.
– Upgrade kit - single operation: Signal
monitoring of the pressure switch P1.
– Upgrade kit - subsequent operation:
Signal monitoring of the pressure
switch P2.
– Upgrade kit swimmer tank: Signal mon-
itoring of the lack of the water fuse and
the temperature sensor.
– Upgrade kit hot water: Supply and con-
trol of the advance pump.
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.
Lack of water fuse in the 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 in the swimmer
tank
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 per-
missible operating pressure is exceed-
ed; water flows outside.
– 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 all extraction locations are closed, the
overflow valve opens and the entire wa-
ter volume will flow back to the suction
side of the high pressure pump. The
high pressure pump is switched off via
the flow switch once the set delay time
has elapsed.
– The remaining water flows back to the
suction side of the high pressure pump
via the overflow valve.
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