INITIAL STARTUP
UNITROL MODEL 8500, 8501, 8550, 8551
17
DEW POINT CONTROL FAULTS, OPTION 8001-03
This
OPTIONAL
DEW POINT controller monitors four measurements and responds as
follows when a fault is detected:
1.
TANK WATER SENSOR FAILURE:
If the control detects temperature, as sampled by
the thermister sensor in the water tank, that is below 20
°
F or above 100
°
F, the display
will show:
The alarm will sound, and a pilot-duty dry contact between terminals
C5
and
NO5
on the
Dew Point controller will close. At the same time, a contact between
C5
and
NC5
will
open. These contacts can be used to monitor a control fault by an outside system.
If this fault is displayed,
the control will turn off the compressor
even if the water
temperature is 3
°
F or more above the
SP
temperature.
2.
HUMIDITY SENSOR FAILURE:
The room humidity sensor is located inside the white
control box near the ON/OFF switch on the control panel. This indicates that this sensor
is feeding a value to the main control of a relative humidity lower than 0
°
F and above
105
°
F. This would happen if this humidity sensor has failed. The display will show:
The alarm will sound, and a pilot-duty dry contact between terminals
C5
and
NO5
on the
Dew Point controller will close. At the same time, a contact between
C5
and
NC5
will
open. These contacts can be used to monitor a control fault by an outside system.
If this fault is displayed,
the control will not turn off the compressor,
but Dew Point
protection will not be active.
3.
3. ROOM TEMPERATURE SENSOR FAILURE:
The room temperature sensor is
located inside the white control box near the ON/OFF switch on the control panel. This
indicates that this sensor is feeding a value to the main control of a relative humidity
lower than 30
°
F and above 120
°
F. This would happen if this temperature sensor has
failed. The display will show:
The alarm will sound, and a pilot-duty dry contact between terminals
C5
and
NO5
on the
Dew Point controller will close. At the same time, a contact between
C5
and
NC5
will
open. These contacts can be used to monitor a control fault by an outside system.
If this fault is displayed,
the control will not turn off the compressor,
but Dew Point
protection will not be active.
Alt
ALH
ALr
Содержание PROCESS 8500
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