Karcher HD 4000 C, HD 6000 C operating instructions Description of Functions

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C. System Function

HD 4000 C / HD 6000 C

2. Description of Functions

Water Inlet

The water is conveyed from the float reservoir to the intake side of the two pumps. The water level in the float reservoir is maintained by the float valve

(2). The incoming water is cleaned in the dirt trap (3). In the case of a float valve failure, the water exits through the overflow

(4). In the event of insufficient feed water volume or failed water supply the low-water sensor (5) sends a fault signal to system control.

Pumps

The electric motor drives both pump ends

(1). The pumps convey the water under high pressure to the pressure side. The starting of the motor opens the pressure relief valve with its upstream filter (7). This action connects pressure and suction sides of the pumps, and no pressure is built up. The motor is able to start free of any load.

High-pressure side

The high-pressure water passes through the overflow valve (8) and the flow monitor

(9)to the high-pressure outlet, and subsequently into the high-pressure tubing system installed by the system owner. The dashpot (13) dampens the water pressure pulsing through the piston sleeve.

Pressure Control

Unused water is returned from the overflow valve to the float reservoir. If all utilisers are inactive, the overflow valve switches to idle-pressure circulation. If the outlet pressure exceeds the maximum operating pressure regardless of the overflow valve, the safety valve (10) opens.

System Control

The pump motor is started with the unlock button (S1). If the volume of water taken drops below 8 +2 litres per minute, then the after running time starts. This amounts to about 15 seconds. If the water consumption remains below the minimum quantity, then the pump stops after expiry of the after running time. Within the immediately following availability time the pump starts due to the drop in pressure caused by the opening of a handgun or by activation of the unlock button. If the water pressure drops due to leakages in the high-pressure network then the pump starts and executes leakage compensation. The availability time ends

nafter approx. 6 hours,

nafter six attempts at leakage compensation,

nafter the switching off of the supply voltage.

After expiry of the availability time the system can only be restarted with the unlock button.

Cooling

During the operation of the pump the solenoid valve (11) is kept in the open position. This allows cooling water to flow through the pressure regulator (12) and circulate through the cooling coils of the motor. The flow of cooling water is set by means of the pressure controller. Once the cooling water has passed through the cooling coils it is returned to the float reservoir.

C2 5.956-648 A10369 (06/98)