Fault
Possible cause
Remedy
The warning tone is activated
(reduced suction performance;
VC 20‑UM‑Y/ VC 40‑UM‑Y).
The filter element is clogged with dirt
or dust.
Switch the automatic filter cleaning
system on then perform the "power
cleaning" procedure: Disconnect
the suction hose, cover the suction
opening with your hand and keep it
covered until three cleaning cycles
have been completed.
Change the filter element if neces-
sary.
See section: 8.1 Changing the filter
element
Blockage in the hose, vacuum cleaner
or power tool dust hood.
Clean the hose and dust hood.
The hose diameter selector switch is
set incorrectly.
See section: 7.3 Hose diameter set-
ting (VC 20‑UM‑Y/ VC 40‑UM‑Y)
Dust is blown out of the appli-
ance.
Dust on the sealing surfaces between
the container and top section of the
appliance.
Clean the sealing surfaces.
The filter element is not fitted cor-
rectly.
Remove the filter element and refit it
correctly.
The filter element is damaged.
Fit a new filter element.
The filter seal is damaged.
Fit a new filter element.
The appliance doesn’t start or
switches itself off after a short
time.
The container level monitoring system
has been triggered.
Clean the container level monitoring
sensors and surrounding area with a
brush.
No battery is detected, i.e. no
LED lights or blinks.
The battery was inserted and
removed too quickly.
Pull the battery out, wait approx. 2
seconds, and then re-insert it.
9.2 Mains-powered operation
Fault
Possible cause
Remedy
The motor doesn’t restart.
The mains circuit breaker has been
tripped.
Reset the circuit breaker. Find the
reason for the overload current if it
trips again.
The container is full.
Switch the appliance off. Empty the
container.
See section: 7.9.2 Emptying the
waste material container when no
dust bag is fitted (collecting liquids)
The appliance switches itself off
or on inadvertently or the user
receives electric shocks (static
discharge).
Electrostatic charge is not dissipated
correctly; the appliance is connected
to an unearthed/ungrounded power
outlet.
Connect the appliance to an
earthed/grounded power outlet; use
an antistatic hose.
The charging station status LED
blinks.
The battery is too hot or too cold.
Bring the battery to room temperat-
ure.
Doesn't switch over to a dis-
charged battery.
No contact.
Reinsert the battery.
The battery was not detected.
Remove the battery from the appli-
ance and contact Hilti.
The motor doesn’t run when set
to “AUTO”.
The electric tool is faulty or is not
plugged in fully.
Check the electric tool for correct op-
eration and plug it in fully.
The automatic filter element
cleaning system doesn’t work.
No suction hose is connected.
Connect the suction hose.
APFC button is in the OFF position
(LED doesn't light).
Press the APFC button.
en
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Printed: 24.03.2014 | Doc-Nr: PUB / 5140202 / 000 / 03
Printed: 28.03.2019 | Doc-Nr: PUB / 5140202 / 000 / 04