GB
UNM STH/STV
2.8
Troubleshooting
Observe the safety instructions!
Problem
A
Protective
motor
switch
interrupts
power supply.
B
Pressure relief does
not function
C
Compressor
not
start
when
switched on.
D
The
compressor
starts
up
briefly
when the switch-on
pressure is reached
or
hums,
switches off auto-
matically.
E
Compressor
continuously.
II/14
Cause
In case of malfunctions (e.g.
overheating;
extension cable too long or
with incorrect cross-section),
the protective motor switch is
tripped.
The pressure relief is shut
down by an interruption of the
power supply or voltage drop in
the mains when the compres-
sor is switched on.
does
Vessel pressure is higher than
switch-on pressure.
Power supply faulty.
Protective motor switch inter-
rupts power supply.
Pressure switch defective
Mains connection cable longer
than permitted or the cross
section is too small.
then
runs
Intake filter badly contami-
nated.
Air consumption of compressed
air tools is too high.
Leakage at compressor.
Excessive condensate in the
vessel.
Compressed air line leaky:
Condensate drain valve is open
or missing.
Remedy
Switch off the compressor. Wait
low
voltage;
a short while. For compressors
with an external protective motor
switch:
Switch on the compressor.
If the protective motor switch is
triggered again: switch off the
compressor. Disconnect the pow-
er supply. Contact the service
partner.
Switch off the compressor. It de-
pressurises. Switch on the com-
pressor.
Relieve pressure in the vessel
until the pressure switch is acti-
vated automatically.
Have the power supply checked
by a qualified person (service
partner).
See item A.
Have
changed by a qualified person.
Check connection cable length
and
Chap. 2.4.4)
Clean or replace intake filter.
Check the air consumption of the
tools. Contact the service partner
Locate leak, contact service part-
ner.
Drain
Chap. 2.6.3).
Check compressed air line, plug
leak.
Close or replace.
actuate
the
the
pressure
cable
cross-section
the
condensate
switch.
switch
(see
(see