Part No.21967 Rev. M June 2017 - 26 - Refrigerated Well GN Series
Refrigeration cont.
GN SERIES REFRIGERATED WELL - SERVICING
Temperature
Regulator
XR40CX
Model XR40CX is a microprocessor based
controller.
It is provided with three NTC or PTC probe
inputs, the first one for temperature
control, the second one, to be located onto
the evaporator, to control the defrost
termination temperature, the third one,
optional, to connect to the HOT KEY terminals to signal a condenser
temperature alarm.
The indicated set-point temperature will be lower than the
air temperature inside the cabinet, because the
refrigeration compressor is controlled in response to the
exit air temperature from the evaporator cooling coil.
The HOT KEY output allows one to programme the
controller by means the HOT KEY programming keyboard.
The instrument is fully configurable through special parameters that can be
easily programmed through the keyboard.
XR40CX
Compressor
Control
The regulation is performed according to the
temperature measured by the thermostat probe
with a positive differential from the set point: if the
temperature increases and reaches set point plus
differential the compressor is started and then
turned off when the temperature reaches the set
point value again.
In case of a fault in the thermostat probe the start and stop of the compressor
are timed through parameters COn and COF.
Parameters are used to control the interval between defrost cycles (IdF), its
maximum length (MdF) and two defrost modes: timed or controlled by the
evaporator’s probe (P2P).
In this cabinet, the start of the defrost cycle is timed, but the cycle will be
terminated as soon as the defrost probe reaches the pre-determined
temperature.
At the end of defrost dripping time is started, its length is set in the FSt
parameter. With FSt =0 the dripping time is disabled
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