Troubleshooting - Hilti VC 20-U Mode D'emploi

running water for cleaning. This may negatively affect the
electrical safety of the appliance. Always keep the grip
surfaces of the appliance free from oil and grease. Do not
use cleaning agents which contain silicone.
For vacuum cleaners of the class M, please note: The
appliance must be handled for cleaning and maintenance
in a way that avoids exposing maintenance personnel
and other persons to any hazards. Use filtered forced
en
ventilation. Wear personal protective equipment. Clean
the maintenance area in a way that prevents hazardous
substances escaping into the surrounding environment.
Vacuum off the outer surfaces of the appliance, wipe it
clean or seal it in suitable container or material before
removing it from an area contaminated with hazardous
substances. This will help to avoid distribution of the
hazardous dust deposited on it.
When maintenance or repairs are carried out, all con-
taminated parts which cannot be satisfactorily cleaned
must be packed in impermeable bags and disposed of in
compliance with the applicable disposal regulations.
A vacuum cleaner of the class M must be subjected to a
technical inspection by Hilti Service or a trained person

9 Troubleshooting

Fault
The audible warning signal
is emitted (reduced suction
power) (VC 20‑UM/ VC 40‑UM).
Dust is blown out of the appli-
ance.
The appliance switches itself off
or on inadvertently or the user
receives electric shocks (static
discharge).
The appliance doesn't start or
switches itself off after a short
time.
The motor doesn't restart.
28
at least once a year to check, for example, for damage to
the filter, air leakage, and to ensure correct operation of
controlling devices.
8.7 Maintenance
WARNING
Repairs to the electrical section of the appliance may
be carried out only by trained electrical specialists.
Check all external parts of the appliance for damage
at regular intervals and check that all controls operate
faultlessly. Do not operate the appliance if parts are
damaged or when the controls do not function faultlessly.
If necessary, the appliance should be repaired by Hilti
Service.
8.8 Checking the appliance after care and
After carrying out cleaning and maintenance, check that
the vacuum cleaner has been correctly reassembled and
that it operates faultlessly.
Test each of the functions.
Possible cause
The dust bag is full.
The filter element is clogged with dirt
or dust.
Blockage in the hose, vacuum cleaner
or power tool dust hood.
The hose diameter setting is incor-
rect.
The filter element is not fitted cor-
rectly.
The filter element is damaged.
The filter seal is damaged.
Electrostatic charge is not dissipated
correctly; the appliance is connected
to an unearthed/ungrounded power
outlet.
The water level cut-out is activated.
The mains circuit breaker has been
tripped.
maintenance
Remedy
Change the dust bag.
See section: 7.4.2 Changing the
plastic dust bag 4
See section: 7.4.1 Changing the pa-
per dust bag / filter fleece
Change the filter element if neces-
sary.
See section: 8.2 Changing the filter
element
Clean the hose and dust hood.
See section: 7.1 Hose diameter set-
ting (VC 20‑UM/ VC 40‑UM)
Remove the filter element and refit it
correctly.
Fit a new filter element.
Fit a new filter element.
Connect the appliance to an
earthed/grounded power outlet; use
an antistatic hose.
Clean the probe and the area around
the probe with a brush.
Reset the circuit breaker. Find the
reason for the overload current if it
trips again.