CombiSteel 7480 Serie Mode D'emploi page 11

9-3 Condenser fan speed regulator
It is standard on the Wall-mounting models forms 4 and 5; furthermore, instead of the fan pressure switch, a
condenser fan speed regulator can be installed on request: when this electronic device, which does not control
directly the gas pressure coming from the compressor but the temperature of gas already condensed, is
employed, the regulation of the condensing temperature is linear and no more "with steps" as it is described
with regard to the fan pressure switch. Practically speaking, there is no more an ON-OFF working of the fan and
the consequent variation of condensation as regards the calibration value, in this case in fact, after a brief initial
period of adjustment, the fans reach a speed that allows to maintain a constant condensing temperature. The
speed regulator is fixed inside the switchboard and it is calibrated in the factory; the speed regulator probe lies
on the contrary in a proper housing placed on the outlet pipe of the condenser.
If, in case of a failure, it is necessary to replace the speed regulator or the corresponding probe and the spare
part is not immediately available, you can anyway set the machine in motion by excluding this regulation. In
order to do it, set the speed regulator bypass switch (fig. 9-3a) (it is inside the switchboard) in the position "1".
After having changed the damaged part, remember to restore the original functioning.
Instructions for the regulation

Change of the setpoint:
The setpoint is the temperature value to which corresponds an outlet voltage of 0 Volt. The setpoint can be
modified by the "Set" trimmer, which has a regulation field from 0 to 60°C. It is calibrated in the factory at
35°C.

Change of the differential:
The differential is the temperature value that, if it is added to the setpoint value, comes to the value
corresponding to the highest outlet voltage (230V). It can be changed by the "Differential" trimmer, within
the limit values 3 and 30°C. It is calibrated in the factory at 15°C.
N.B. The trimmers "V min" and "Cut off" have to be set at 0%.
9-4 Liquid Gas line filter
It is on the liquid gas line, just after the liquid receiver or, in the units on which there is not the receiver, on the
outlet pipe of the condenser.
9-5 Liquid gas line solenoid valve
It is installed only on request (standard on the evaporator of the Bi Block units forms 4 and 5). It is installed so as
to interrupt the liquid flow when the unit has to stop for the defrost or as the programmed temperature value
has been reached: in this way the stop of the unit takes place when the compressor is in vacuum.
9-6 Capillary tube
It lies at the entrance of the evaporator and it allows the gas, coming from the liquid gas pipe, to reach the
evaporation pressure. It is present in all units, except for the Bi Block units forms 4 and 5.
9-7 Thermostatic valve
It is installed only on request instead of the capillary tube, but it is standard on Bi Block units forms 4 and 5. Even
though it performs the same function, it is undoubtedly a more sophisticated device that, unlike the capillary
tube, can be regulated. The valve calibration is executed in the factory.
9-8 Liquid indicator
It is installed only on request, but it is standard on the Bi Block units forms 4 and 5. It is on the left side of the
unit and it is visible from outside. The indicator has usually to be controlled when the unit is working: if you
notice a persistent transit of gas bubbles, this can mean that there is a lack of gas in the system; on the contrary
if the indicator is clear and you notice only some sporadic transit of bubbles, this means that the gas quantity is
correct.
9-9 Suction pressure regulating valve
It is installed on some low temperature units with defrost by hot gas and up to form 3. It serves to maintain the
compressor suction pressure during the defrost within acceptable values. It lies on the suction pipe, near the
compressor. It is calibrated in the factory.
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