Troubleshooting - Carel MC Serie Manual Del Usuario

14. Troubleshooting

Line Problem
1 The humidifier has been
powered and switched ON
but does not work.
2 The unit is ON but does
not start working.
3 The display shows "SEA"
and the humidifier does
not start.
4 The display shows "ALA"
and the humidifier does
not start.
5 Water saturation with
plenty of drops due to
the OFF routine of the fan. to force the humidifier into
The 'limit' probe does
not stop the humidifier.
6 The output air pressure
does not reach 2.1bar.
Cause
C1: Cabinet not powered.
C2: Blown fuses.
C1: The value measured by
the probe is higher than
the set point.
C2: Wrong regulation logic.
C3: The regulator does
not work (faulty regulator).
NB: Proportional model,
just one or both regulators.
C1: Disconnected or
short-circuited probe.
C2: Out-of-range signal probe. S2: Turn ON the MC humidifier and check that:
C3: Probe not suitable for
the instrument.
There is no remote ON/OFF
command: the contact between
terminals 1 and 2 is open.
The fan has stopped before
the "limit" probe intervened
an OFF routine.
C1: The compressor is not
capable of supplying the
required air (inlet
pressure always <5bar).
C2: Incorrect setting of the
pressure reducer.
C3: Proportional version only:
the value measured by
the probe/s is approaching
the set point (modulation
in progress).
C4: Troubles on the feedback
air system:
a) the actuator is not capable
of opening the valve;
b) the probe output signal is
too high with respect to
the actual pressure value;
c) the command of the AD4
card towards the actuator
is incorrect.
Solutions
S1: Check tension between terminals L and N (220Vac).
S2: Check the fuses on the transformer.
S1: Check set point and differential with the value
indicated by the probe.
S2: Check the regulation logic parameters.
(ON/OFF version: see C01 and C02;
Proportional version: see C22 and C23).
See Operation Guide page 25.
S3: Check that power supply to terminals 5 and 6 (G0)
on the AD4 card is over 5Vdc.
NB: Proportional models, just one or both regulators.
S1: Be sure that the probe is connected to the
terminals of the cabinet.
a) power supply between terminals 3 and 5
(6 and 8 in duct models) is correct (+24Vdc);
b) the probe signal between terminals 3 and 4
(6 and 7 in duct models) ranges between 0
and 1Vdc;
c) the sensor is not wet.
S3: Be sure that the output probe signal is suitable
for the signal of your CR72 (0-1VDC).
a) Check continuity between terminals 1 and 2:
an open contact indicates a power difference.
b) Check the connections at input D.IN and REF
of your CR72.
Command the remote ON/OFF (terminals 1 and 2)
by means of a flow switch or a differential pressure
switch: this is the only way to avoid this problem.
S1: Check the capacity of the compressor in relation
to the overall consumption of the installation.
S2: Set again the pressure reducer (see page 21).
S3: Check again the selected set point and differential in
relation to the probe values (see page 27/28)
S4: a) the command output towards the AD4 card, T1
and T2 commands 0-20V phase cut. With 0Vdc
between T1 and T2 the valve remains comple
tely closed. With 20Vdc the valve is completely
open.
If you want to check the integrity of the valve,
remove the actuator (this forces the valve to close)
then press the cylinder/spring body.
b) With pressure = 2.1bar between terminals Ic and
G0 the signal must be 3.25Vdc, otherwise the probe
signal is out-of-range.
c) Disconnect the cable to terminal Ic: the signal
between terminals T1 and T2 must reach 20Vdc.
If not, there are troubles on the AD4 card.
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Cod. +030221742 rel. 2.2 – 16.06.2005