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
25 (32)
PROBLEM SOLVING
Identifying and solving problems is made easier by the microprocessor control which, in the event of an alarm:
•
activates the alarm relay as well as the red LED and buzzer on the user terminal
•
displays an alarm condition on the user terminal
•
describes, via the appropriate routine, the nature of the alarm and the possible solution.
If the HP pressostat or electric heater safety thermostat intervene they must be re-set manually using the button on
the device.
Many problems can be caused by loose terminal connections. In the event of an alarm,
check that all wires are securely fixed in the terminals
.
If there is a fault, contact the nearest authorised Service Centre, giving the nature of the fault and any probable
causes. Always consult the Microprocessor Control Manual included with the unit - many problems which seem to
be faults are simply a question of incorrect or incomplete programming of the control.
PROBLEM
POSSIBLE CAUSE
CHECK / REMEDY
NO POWER
A) No power to the unit electrical panel
and/or no power to the auxiliary circuit.
1) Check that power is on and the unit main switch
on the electrical panel is closed; check that the IM
automatic circuit breaker is set..
(The yellow LED on the mP20 board is
off).
2) Check the auxiliary circuit 24V fuse and the
fuse on the mP20 board
The message appears:
WARNING! PHASE SEQUENCE ERROR
The phase sequence is inverted (models
with 400V/3N/50Hz power supply).
Check that both LEDs on the RSF phase
sequence relay are on. If not, disconnect the
power supply then swap two of the power supply
phases.
If the alarm comes when the unit is operating the
LP pressostat may have tripped: Check the
pressure in the refrigerant circuit in the sec tion
subject to evaporation pressure.
THE UNIT DOES NOT WORK
The control panel does not start the
unit.
Check that the control panel connectors are
correctly located in their sockets; see
mP20/W
control panel instruction manual.
.
Check the control panel for alarms
See
mP20/W
control panel instruction manual
The circuit does not receive the
function command in remote control
mode
With a remote control system, check that the
contact between terminals 20 and 50 is
closed
