7.4 Troubleshooting
Symptom Possible cause Test Solution
Display
dark/No
function
Missing input power
See Table 4.5
Check the input power source.
Missing or open fuses or circuit
breaker tripped
See open fuses and tripped circuit breaker in
this table for possible causes
Follow the recommendations provided.
No power to the LCP Check the LCP cable for proper connection
or damage
Replace the faulty LCP or connection cable.
Shortcut on control voltage
(terminal 12 or 50) or at control
terminals
Check the 24 V control voltage supply for
terminals 12/13 to 20-39 or 10 V supply for
terminals 50 to 55
Wire the terminals properly.
Wrong LCP (LCP from VLT
®
2800
or 5000/6000/8000/ FCD or FCM)
Use only LCP 101 (P/N 130B1124) or LCP
102 (P/N 130B1107).
Wrong contrast setting
Press [Status] + [
▲
]/[
▼
] to adjust the
contrast.
Display (LCP) is defective Test using a different LCP Replace the faulty LCP or connection cable.
Internal voltage supply fault or
SMPS is defective
Contact supplier.
Intermittent
display
Overloaded power supply (SMPS)
due to improper control wiring
or a fault within the adjustable
frequency drive
To rule out a problem in the control wiring,
disconnect all control wiring by removing the
terminal blocks.
If the display stays lit, then the problem is in
the control wiring. Check the wiring for
short circuits or incorrect connections. If the
display continues to cut out, follow the
procedure for display dark.
Motor not
running
Service switch open or missing
motor connection
Check if the motor is connected and the
connection is not interrupted (by a service
switch or other device).
Connect the motor and check the service
switch.
No line power with 24 V DC
option card
If the display is functioning but no output,
check that line power is applied to the
adjustable frequency drive.
Apply line power to run the unit.
LCP Stop Check if [Off] has been pressed Press [Auto On] or [Hand On] (depending on
operation mode) to run the motor.
Missing start signal (Standby)
Check 5-10 Terminal 18 Digital Input for
correct setting for terminal 18 (use default
setting)
Apply a valid start signal to start the motor.
Motor coast signal active
(Coasting)
Check 5-12 Coast inv. for correct setting for
terminal 27 (use default setting).
Apply 24 V on terminal 27 or program this
terminal to No operation.
Wrong reference signal source Check reference signal: Local, remote or bus
reference? Preset reference active? Terminal
connection correct? Scaling of terminals
correct? Reference signal available?
Program correct settings. Check
3-13 Reference Site. Set preset reference
active in parameter group 3-1* References.
Check for correct wiring. Check scaling of
terminals. Check reference signal.
Motor running
in wrong
direction
Motor rotation limit
Check that 4-10 Motor Speed Direction is
programmed correctly.
Program correct settings.
Active reversing signal Check if a reversing command is
programmed for the terminal in parameter
group 5-1* Digital inputs.
Deactivate reversing signal.
Wrong motor phase connection
See 5.5 Checking Motor Rotation.
Diagnostics and Troubleshoo...
VLT
®
HVAC Drive Instruction Manual
MG11AJ22 - Rev. 2013-09-13 49
7 7
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