Functional Description Of The Control; Hot Water/Cold Water Solenoid Valves; Water Shortage Safeguard; Heating - Kärcher HDS-E 8/16-4 M Series Service Manual

5.14 Functional description of the control

5.14.1Hot water/cold water solenoid valves

Pump start
Switching from warm to cold water (or vice-ver-
sa) with the high pressure pump running
Pump stop

5.14.2Water shortage safeguard

If the water level in the boiler sinks, the lack of water
fuse is triggered. The following processes are trig-
gered by the control if there is a lack of water:
Immediately
After 120 seconds

5.14.3Heating

The control electronics limit the water temperature in
the "Eco" operation setting to 60 °C and to approx. 80
°C in warm water operation mode.
Switch-on conditions for the heater:
Thermostat in position "Eco" or warm water oper-
–
ation.
Lack of water fuse has detected a sufficient water
–
level for 5 consecutive seconds.
The water temperature at the temperature sensor
–
is lower than the selected temperature at the ther-
mostat.
The heater is only switched on if all three conditions
are fulfilled.
Switch-off conditions for the heater:
Immediately
Immediately
10 seconds after the temperature selected on
the thermostat is reached
After 5 hours

5.14.4Reciprocating pump (system care)

Dosing time 0.2 seconds. (The reciprocating pump
–
is energised with voltage for 0.2 seconds and ex-
ecutes a stroke of the reciprocating piston during
this time).
The reciprocating pump is only activated if the mo-
–
tor contactor is operated.
If a dosing is in progress, the motor contactor will
–
switch off with a delay of 0.4 seconds after the re-
46
English 5.906-548.0 Rev. 00 (04/12)
First, the respective solenoid valve for cold or warm water
will open and 0.3 s later, the high pressure pump starts up.
Both solenoid valves are opened for 0.5 s simultaneously.
The currently open solenoid valve (warm or cold water)
closes 5 seconds after the high pressure pumps is shut off.
The heating element in the boiler is switched off. Indicator
lamp for lack of water lights up.
The high pressure pump is stopped. The indicator lamp for the
pump (oil tin) blinks three times.
Water temperature of 90 °C or more. Indicator lamp for boiler
fault blinks once.
In case of water shortage. The indicator lamp for the pump (oil
tin) blinks three times.
avoids frequent switching of the contactors during normal op-
eration.
If no RFID tag is detected or once the 5-hour trailing time has
elapsed (indicator lamp system care blinks once).
ciproating pump so that the dosing can be con-
nected.
If the system care tank is empty, the reciprocating
–
pump is not activated (dry run protection).