Care Of Compu-Purge Sensors; Lcd Display Information; Indicators And Alarms - Sigma HRD Serie Manual De Instrucciones

15. Remove the set plug and reinsert the white
receptacle.
16. Reinsert the conduit connector in outlet piping.
The high-humidity alarm is now set.
To put the dryer back into service, follow the start-up
instructions on page 1-9.

Care of Compu-Purge Sensors

Temperature Sensor
The temperature sensor located in the dryer inlet pip-
ing. The sensor relays a DC millivolt signal to the mi-
crocomputer in proportion to inlet air temperature. If
this sensor malfunctions, it must be replaced.
Pressure Sensor
Inlet and outlet pressure are sensed by a pressure trans-
ducer in the center bottom of the electrical box. Two
cables connect the transducer to the control board, on
the inside of the door, at "CON 7" and "CON 10."
Control air is supplied to the transducer from the No. 2
connector of the 3-way valve attached to the underside
of the electrical box.
If the pressure sensor malfunctions, replace the pres-
sure transducer and cables.
DANGER
EXPLOSION HAZARD
Dismantling or working on any component of
the compressed air system under pressure
may cause equipment damage and serious
injury. Before dismantling any part of the dryer
or compressed air system, completely vent the
internal air pressure to the atmosphere.
To remove the transducer and cables, remove the bulk-
head fitting on the underside of the electrical box; dis-
connect the control air line to the transducer;
disconnect the cables from the circuit board.

LCD Display Information

Low Inlet Air Pressure Alarm (Below 65 psig)
Display =
LOW INLET AIR PRESSURE
High Inlet Air Pressure
Display =
WARNING!! HIGH INLET AIR PRESSURE
Sensor Alarm for Pressure Transducer Failure (No
Signal)
Display =
LOW INLET AIR PRESSURE
Note: Dryer will enter Standby Mode.
Sensor Alarm for Pressure Transducer Failure
(High Signal)
Display =
PRESSURE SENSOR MALFUNCTION
HRD and HRD-EM Series (Bulletin 378)
High Inlet Temperature Alarm (Over 120°F)
Display =
HIGH INLET AIR TEMPERATURE
Sensor Alarm for Temperature (Open circuit)
Display =
750°F–TEMPERATURE SENSOR MALFUNCTION
Sensor Alarm for Temperature
(Transducer/control board malfunction)
Display =
390°F–TEMPERATURE SENSOR MALFUNCTION
Sensor Alarm for Temperature (Sensor shorted)
Display =
32°F–TEMPERATURE SENSOR MALFUNCTION
Switch Failure Alarm
Display =
WARNING!! FAILURE TO SWITCH TOWERS
High Humidity Alarm
Display =
WARNING!! HIGH HUMIDITY CONDITION
Standby Mode
Display =
NO LOAD ON DRYER
IN STANDBY MODE: SAVING PURGE AIR
Coming out of Standby Mode
Display =
STANDBY MODE COMPLETE
USING STANDARD VALUES
Overload Indicator
Display =
DRYER IS OVERLOADED (MAX PURGE MODE)
More than one functional problem
Display =
MULTIPLE ERRORS: CHECK STATUS LIGHTS

Indicators and Alarms

Some malfunctions or component failures will cause
the dryer to enter a fixed-cycle mode using 15% of the
design airflow to regenerate the vessel. Other failures
may cause it to enter Standby Mode.
Low Inlet Air Pressure
The front panel indicator will light immediately when
the air line pressure drops below 65 psig. If the low
pressure condition is not corrected by the end of the
offstream tower's regeneration cycle, the dryer will
enter Standby Mode. When the pressure increases to
above 65 psig, the dryer will automatically restart.
Pressure Transducer Malfunction
No Signal: The sensor malfunction indicator will not
light when a zero signal condition occurs. This condi-
tion also indicates that there is no compressed air pres-
sure. The low inlet air indicator will light and the dryer
will enter Standby Mode. This may happen if the con-
nector (CON 7) on the control board is not securely
plugged in, if there is an open wire in the transducer
circuit, or if the transducer is faulty.
High Signal: The front panel sensor malfunction indi-
cator will light immediately. Transducer output should
be checked using a DC millivolt meter. If the trans-
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