Troubleshoot ing l 6-9
6
Troubleshooting
Alarms
• Shutdown (A#): The dryer has automatically shut down because it has detect-
ed a serious problem that could damage your material or dryer.
• Passive (P#): The dryer continues to operate, but warns of a problem that could
prevent correct drying of your material. If ignored, this problem could lead to a
condition that will shut down the dryer.
Problem
A34 & P28 - Return Air
Temperature RTD Integrity
– The dryer continues to run
with a passive alarm. (The
return air temperature on
W1600-5000 dryers is meas-
ured at the inlet to the desic-
cant wheel. W1600-5000 dry-
ers designed prior to August
2007, the return air tempera-
ture is measured at the inlet
to the process blower.)
A35 & P8 - Regeneration
Temperature Loop Break –
The regeneration temperature
is outside of the operator
entered deviation alarm band
(see Regeneration
Temperature Deviation pas-
sive alarm) and the regenera-
tion temperature is not moving
towards the setpoint at a rate
greater than specified. Default
values are 2°F {1°C} over 40
seconds.
A36 - Control
Communications Watchdog
- The display board has lost
communications with the
control board.
Possible cause
There is a loose connection in the
wiring leading to the RTD.
The connection of the RTD plug on the
control board is loose.
The return air RTD has failed.
The control board has failed.
The regeneration heater has failed.
The regeneration RTD is loose or has
fallen out.
The regeneration blower is not running.
The output on the control board has
failed or the fuse is blown.
Plugs on wire harness between the
display and control boards are loose or
not wired correctly.
Display board or communications
boards have failed.
Solution
Check the RTD plug connections,
make necessary repairs.
Check the plug connection and tighten if
needed.
Replace the return air RTD.
Replace the control board.
Check the heater fuses, and resistance
across each leg of the process heater.
Check the regeneration RTD and tighten
if needed.
Correct the cause of the non-functioning
blower.
Replace the control board or fuse.
Make sure plugs are tight on board
connections and match the wiring dia-
gram.
Replace the defective boards.
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