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PROBLEM
B
Excessive air pressure drop.
C
The dryer is obstructed and
the air does not flow.
CAUSE
A9
No refrigerant fluid in the
circuit. If you are in doubt
concerning the refrigerant
charge level, measure the
manometric temperature
(pressure) on the refrigerant
compressor suction side
using the Schraeder valve
provided. Gradually change
the airflow through the
dryer in such a way that the
dryer operates without
capacity steps; the
manometric temperature
(read on the temperature
scale of the refrigerant
utilized) must vary from
approximately -3 °C
(26.6 °F) to 0 °C (32 °F);
if the manometric
temperature is lower than
these values the circuit
probably contains
insufficient refrigerant.
A10
Solenoid valve on the low
pressure line not functioning
correctly.
B1
See A2 and A3.
B2
There is an increase in the
pressure drop and the dryer
freezes.
B3
Exchanger obstructed by
impurities entrained by the
compressed air.
C1
Incorrect position of
temperature probe so the
thermal mass has fallen
below zero thereby freezing
the condensate (it may have
occurred that following
maintenance work carried
out inside the dryer the
temperature probe has
become dislodged)
C2
Incorrect setting or
malfunctioning of the
electronic controller or
alteration of the setpoint
(if required by the electronic
controller supplied with the
unit, see Chapter 7
"Electronic controller
RF ") will cause ice
formation.
C3
Temperature probe not
calibrated.
SYMPTOM
A9.1
• Compressor doesn't stop even
if there is a little air flow;
• frosting on the evaporator
capillary inlet;
• power absorption lower than
expected;
• also see A1.1
A10.1
See A1.1
B1.1
• Dew-point temperature
increased (see A1.1);
• pressure downstream of the
dryer lower than expected.
B2.1
See point C.
B3.1
Pressure down-line from
the dryer lower than
expected.
C1.1
The value measured by
the probe remains above
0 °C (32 °F) even when
the compressor runs for
prolonged periods
(e.g. more than
10-15 minutes) without
any compressed air flow.
C2.1
The compressor fails to
stop even though the dew
point temperature is very
close to 0 °C (32 °F).
C3.1
Apparently everything is
functioning correctly but
there is no air flow.
REMEDY
Call in a qualified refrigeration
engineer to check for leaks and
eliminate them. Have the circuit
charged by a qualified
refrigeration engineer.
Check operation of the solenoid
valve. If necessary, renew the
solenoid valve coil or the entire
solenoid valve.
Reduce the compressed air flow
and pressure to within rated
limits.
See point C.
Renew the exchanger.
Correct the position of the probe
in the socket by inserting it
correctly.
Increased the setpoint by 1 or
2 °C (1.8...3.6 °F) (if envisaged
by the electronic control unit
supplied with the unit, see
Chapter 7 "Electronic controller
RF "). If this doesn't solve the
problem, renew the control
board.
Use a tester to check the
impedance of the probe at
20 °C / 68 °F (the value should
be 12.1 k
.
Renew the probe if necessary.
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