Flooded type water cooled screw chiller (PCB Control) MCAC-CTSM-2012-11
60
EXV Troubleshooting:
Problem Reason Solution
Measured
superheat
value is
incorrect
Measured superheat
value is incorrect
Check that the measured pressure and temperature
sensors correctly and the correct position.
Check on the drive set minimum and maximum
pressure pressure sensor parameter with the range
of pressure sensors installed in line.
Check sensor electrical wiring is correct.
Set the wrong type of
refrigerant
liquid back to
the compressor
during the
control
Valve type setting error Check and correct valve type parameters
Valve connection error
(rotation in the opposite
direction) and is open
And manual control valve is completely closed or
open, to check the valve rotation. A fully open valve
Superheat can be decreased, and vice versa so
that the superheat values have increased. If the
valve is rotating in the opposite direction, check
electrical wiring.
Superheat setting is too
low
Check superheat setting. Beginning to set 12 ° C,
check to make sure there is no return of liquid. Then
gradually reduce the set value, but always returning
to ensure that no liquid.
Low superheat protection
is invalid
If low superheat value of long duration and the valve
closes slowly, then increase the degree of protection
of low superheat threshold and / or protection to
lower superheat integration time. The beginning of
the threshold value is set lower than the superheat
setting 3 ° C, points time is set to 3-4 seconds. Low
heat and then gradually reduce the threshold and
increase the integration time, check to make sure the
under any operating conditions there was no return
of liquid.
Valves damaged or
connected incorrectly the
stator
The stator and the valve and disconnect the cable
connection, with ordinary measuring coil resistance
tester.
Two coil resistance should be around 36 Euro.
Otherwise, replace the stator. Finally, check the
connection of electric drive cable wiring.
Valve can not close Always check the superheat value is too low (<2 ° C)
and the valve position is always 0 step. If the above
situation, the valve is set to manual control and
completely shut down. If the superheat value is
always low, check the electrical wiring and / or
replacement the valve.
Often to control the
settings in the refrigerated
cabinet set "Start at the
valve opening degree
control" parameter too
High (only for composite
refrigerated cabinet)
In all uses are reduced" began to control the valve
opening degree" parameter values, make sure to
control the temperature will not be affected
Liquid only
during the
defrosting
returned to the
compressor
( only
applicable to
composite
refrigerating
cabinet )
Defrosting control after the
pause time is too short
Increasing the " defrosting valve control delay"
parameter values
Defrosting and reaches
operating conditions
before drive the measured
degree of superheat
temperature is very low,
and continued for a few
minutes
Check and confirm the LowSH threshold is higher
than the measured value of the superheat, and
activate the corresponding protection function
( integration time > 0 seconds ). When necessary,
reduced integration time
Drive the measured Setting a more sensitive parameter, so that the valve
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