Karcher HDS 7-12-4 M - Manual (Page 28)

– 4
– While reducing the water supply at the
pump head or with the Servopress -
regulation the overflow valve opens and
part of the water flows back to the pump
suck side.
– If the hand-spray gun is closed, so that
the whole water flows back to the pump
suck side, the pressure switch at the
overflow valve shuts down the pump.
– If the hand spray gun is opened, the
pressure switch on the cylinder head
turns the pump back on.
The overflow valve is set by the manufac-
turer and sealed. Setting only by customer
service.
– The safety valve opens, when the over-
flow valve resp. the pressure switch is
broken.
The safety valve is set by the manufacturer
and sealed. Setting only by customer ser-
vice.
– The water shortage safeguard prevents
the burner to be turned on when there is
water shortage.
– A sieve prevents the contamination of
the safeguard and must be cleaned reg-
ular.
– The temperature stop switches off the
machine when the waste gases have
reached very high temperatures.
ṇ
Warning
Risk of injury! Device, tubes, high pressure
hose and connections must be in faultless
condition. Otherwise, the appliance must
not be used.

Lock parking brake.
Figure 3
Caution
Hook the electric supply line into the cable
guide of the right handle bow. Ensure that
the cable is not damaged.
Note: Push the bottle in securely to pene-
trate the closure. Do not remove bottle until
it is empty.
Note: To protect the device, the burner is
switched off 5 hours after the system care
bottle is empty.
– The system care prevents the calcifica-
tion of the heating spiral while operating
with calciferous tap water. It is dosed
into the supply in the float container
drop by drop.
– The metering is set to medium water ri-
gidity by the manufacturer
Note: A system care bottle is included in
the delivery.

Replace the system care bottle.
 Determining the hardness of tap water:
– through the public water supply works,
– using a hardness tester (order no.
6.768-004)
 Set the service switch according to the
water hardness in the table.
Note: Observe the following when using
system care Advance 2 RM 111:
– Calcification protection: See table
– Pump care and black water protection:
Set the service switch to at least setting 3.
Overflow valve with two pressure
switches
Safety valve
Water shortage safeguard
Temperature stop for exhaust gases
Start up
Installing the handle
Replace the system care bottle
Adjusting the dosage of the system
care Advance RM 110/RM 111
Water hard-
ness (°dH) Scale on the service switch
<3 OFF (no dosing)
3...7 1
7...14 2
14...21 3
>21 4
28 EN