Water Pump Standstill Detection - HAKO Scrubmaster B 120 R Service Booklet

8. Water pump

8.2 Water pump standstill detection

If the pump cannot convey freely because the water cannot run freely through
the hoses to the brush, the so-called water pump standstill detection becomes
effective.
Automatic water pump standstill detection:
The electronics offers the option to protect the water pump if the pump can no longer
convey freely.
This means: If the pump sucks water from the tank but cannot further convey the water to
the brushes, pressure builds up behind the pump. Without the protection through the
electronics, the pump would now always pump against this pressure and could thus be
damaged.
The electronics detects that the pump cannot convey freely and automatically switches the
pump OFF for 2 seconds.
After these 2 seconds have expired, the pump is briefly switched back on while
simultaneously measuring whether the pump can now convey freely again or whether the
water supply to the brushes is still blocked.
If the pump can convey freely, it remains switched on in the selected stage.
If there is, however, still counter pressure, the pump is switched off again for 2 seconds.
This is repeated until the error has been eliminated.
Sheet 68