
173 of 222 pages
Operating and service manual
959
RH sens sup LO
Warning
Description
Controller Internal Voltage Reference Fault
Cause
Indication of controller internal voltage reference fault
Trouble
shooting
Possible causes:
• Defect power supply for controller PCB.
• Defect relative humidity sensor.
• Defect controller PCB.
Accompanied alarms:
• There may be sensor alarms, especially AL 302.
• AL 801 will be activated during FT- or PTI test.
Trouble shooting:
1.
Check if there are other active (sensor) alarms. Clear these alarms first
using their trouble shooting.
2. Access the ”special menu” by pressing
for more than 3 sec. Scroll
down until you see the label ”
U RH
” in the display. The value of ”
U RH
”
should be in the range between 16 and 32. While displaying ”
U RH
”,
disconnect RH from the terminals PCB, and:
- If “
U RH
” is now within the correct range, the RH sensor is defect.
Replace the relative humidity sensor, RH.
- If “
U RH
” is still outside the above range, the controller PCB is defect.
Replace the controller door.
Criteria
Reference voltage RH below 12.0V DC
Controller
action
None
Log
X
Alarm
Alarm light
Off
Consequence
Elimination
Log data
Parm 1
Parm 2
Parm 3
Parm 4
Parm 5
Active/Inactive Low limit High limit
Actual value A/D channel