Unloader Valves; Heating Coils - Kärcher HDS4.0/22 Dealer's Manual

Maintenance
Maintenance & Service
Spray Nozzles:
Each machine is equipped with one or more spray
nozzles, depending on the model. Different spray
nozzles are calibrated for each machine, depending on
the flow and pressure of that particular model. Spray
nozzles vary in bore size and angle of spray. Popular
spray angles are 0°, 15°, 25°, 40°. When ordering,
please specify size and angle of nozzle. Nozzle size for
each machine is located on the serial plate.

Unloader Valves:

Unloader valves relieve pressure in the line when a
spray gun is closed. Unloader valves are preset and
tested at the factory before shipping. Occasional
adjustment of the unloader may be necessary to
maintain correct pressure. For valve adjustment
contact your nearest dealer or call technical support.
Tampering with the factory setting may cause personal
injury and/or property damage, and will void the manu-
facturer's warranty.
Winterizing Procedure:
Damage due to freezing is not covered by warranty.
Adhere to the following cold weather procedures
whenever the washer must be stored or operated
outdoors under freezing conditions.
It is necessary to protect your machine against freezing
when temperatures drop below 32° F. Siphoning a
small amount of antifreeze into the system is recom-
mended. This is done by pouring a 50-50 mix of anti-
freeze and water into the float tank and then siphoning
100% antifreeze through the detergent line with the
pump on. If compressed air is available, an air fitting
can be screwed into the float tank strainer fitting, and by
injecting compressed air, all water will be blown out of
the system. The use of a draft diverter will prevent the
wind chill factor from freezing the coil.
Low Pressure Diagnosis:
(Machines with spray gun)
Refer to Troubleshooting Chart for low pressure. If the
trouble is found to be either the unloader or the pump,
your next step is to determine which is the problem.
This can be done by eliminating the unloader from the
system and attaching the 50' discharge hose directly to
the pump. If high pressure is developed in this manner,
the pump is good and the unloader needs to be
repaired or replaced. If low pressure is still present,
then the pump needs repairing.
26 Karcher Liberty HDS Stationary Dealer's Manual 9.801-508.0 - AY
CAUTION: When using this procedure to test
components keep the spray gun open at all times.
High Limit Hot Water Thermostat:
For safety, each machine is equipped with a high limit
control switch. In the event the temperature of the water
should exceed its operating temperature, the high limit
control will turn the burner off until the water cools.
Pumps:
Use only SAE 10W-40 non-foaming oil. Change oil after
first 50 hours of use. Thereafter, change oil every year
or at 500 hour intervals. Oil level should be checked
through use of the dipstick found on the top of the pump
or by the red dot visible through the oil gauge window.
Oil should be maintained at that level.

Heating Coils

To Check Water Heater Coil for Leaks:
With the main burners "OFF" start the pumping unit and
allow it to run for a few minutes. Check into the burner
compartment with a drop light or flashlight. If no leaks
are visible, then water dripping from coils is condensa-
tion from the flue gases when the burners are on.
Condensation from Heating Coil:
When cold water is being pumped into the water heater
coils, and the burners are on, condensation will form on
the coils and drip down into the burner compartment,
giving the appearance of a leaking coil, particularly on
cold humid days.
Descaling Coils:
In alkaline water areas, lime deposits can accumulate
rapidly inside the coil pipes. This growth is increased
by the extreme heat build up in the coil. The best
prevention for liming conditions is to use high quality
cleaning detergents. In areas where alkaline water is
an extreme problem, periodic use of Karcher Coil
Descaler (part # 9.803-742.0) will remove lime and
other deposits before coil becomes plugged.
Periodic descaling of the heating coil is
recommended so please consult your local Landa
Dealer for instructions.