Operating and service manual
98 of 222 pages
301
RH short
Warning
Description
Relative Humidity Sensor Short Circuit
Cause
Indication of short-circuited relative humidity sensor
Trouble
shooting
Possible causes:
•
Relative humidity sensor RH or cable defective.
• X1 cable is defect.
• Controller PCB defective.
Accompanied alarms:
•
AL 302.
Trouble shooting:
Disconnect the cable for RH from the connector PCB according to the wiring
schematics inside the control cabinet and from the RH sensor.
1) If the cable by inspection is defect, replace cable.
2) Dismount the sensor from the cable. Dismount the cable from terminal 22
in X35 on the interface/terminal block. Measure the resistance between the
signal wire coming from the sensor and terminal 21 and terminal 23 at the
interface/terminal block. If the resistance is less than (<) 230 Ω, the cable is
defect and must be replaced.
3) Mount the cable for RH in controller cabinet and on the sensor. Disconnect
signal wire on interface/terminal block PCB. Measure voltage between wire
and GND on the interface/terminal block PCB. If voltage is below 0.5V
DC, sensor or connection between sensor and cable is defect. If voltage is
between 0.5V DC and 10V DC, continue to 4).
4) Mount signal wire. Measure voltage between SIGNAL and GND. If voltage is
between 0.5V DC and 10V DC and this alarm is still active, replace controller
door.
Before replacing controller door see Trouble shooting for Star Cool
Controller p.56
Criteria
Value below low alarm limit 5%
Controller
action
None
Log
X
Alarm
X
Alarm light
Off
Consequence
Dehumidification impossible
Elimination
When sensor value becomes valid, it is marked as inactive in alarm list and may then be
deleted.
Log data
Parm 1
Parm 2
Parm 3
Parm 4
Parm 5
Active/Inactive Low limit
High limit
Current