OPERATION AND MAINTENANCE MANUAL
Wall Mounted 0121…0661
Monobloc Wall Mounted Unit - WMA/WMF 0121-0181-0251-0281-0331-0551-0661 - Rev. 2.0. - Date: 18-07-2000 EN
29 (32)
COMPRESSOR
PROBLEM
POSSIBLE CAUSE
CHECK/REMEDY
THE COMPRESSOR DOES NOT WORK
A) Protection device against short circuit is
switched on.
Restore the magnetic switch lever; check cause of
the short circuit
.
Before restarting the compressor
check the
.
heating element and the winding
continuity of the motor.
B)The internal protection of the compressor
is switched on.
see
‘
COMPRESSOR INTERNAL PROTECTION
DEVICE SWITCHES ON’
C) The contactor doesn’t work.
Check the contacts and the main switch coil.
COMPRESSOR INTERNAL PROTECTION
DEVICE SWITCHES ON
A) Lack of phase (unit power supply
400V/3N/50Hz)
Check the compressor winding heating elements,
after re-setting, measure the voltage and the
absorption of the three phases.
B) Motor overload.
Check that the unit is functioning within the pre-set
limits.
C) Power supply voltage is too high or too
low.
Check the unbalance between the phases of the
three phase power supply are within 2%.. For
monophase components the voltage must be
between -10% and +6% the nominal value
.
D)Blocked rotor.
Replace the compressor.
THE COMPRESSOR IS NOISY
A) The compressor is damaged.
Call the nearest Help Center to replace the
compressor.
B) Liquid return to the compressor.
Check the functioning and overheating of the
expansion valve.
ELECTRIC HEATERS
PROBLEM
POSSIBLE CAUSE
CHECK/REMEDY
ELECTRIC
HEATERS
DO
NOT
The safety thermostat of the heating
elements is switched on.
Airflow is insufficient see “LOW AIRFLOW”.
Check the continuity of the safety thermostat
connection to the control system.
The contactor doesn’t work.
Check the contactor contacts and the electric coil
.
Protection device against short circuit is
switched on.
Check the cause of the short circuit and re-set the
automatic switch lever IM.
