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Troubleshooting l 6-5
Shut Down Alarms
If the red Acknowledge Alarm LED is blinking, the alarm is a shutdown
alarm. The dryer will shutdown automatically to prevent damage to the
equipment or personnel. Note that once the Acknowledge Alarm button is
pressed once, the blinking red LED becomes solid.
Possible cause
The process high temperature setpoint is
not at least 37°F (3°C) above the drying
setpoint.
The RTD temperature probe is not
installed correctly.
The air lines are restricted or loose.
Process RTD is loose or has fallen out.
The process heater has failed.
The air lines are restricted or loose.
There is an air flow blockage or loose
hoses.
The isolation contactor failed in the
closed position.
The heater solid state relays (SSRs)
failed.
Solution
Reset the process high temperature set-
point at least 37°F (3°C) above the dry-
ing setpoint.
Make sure the RTD temperature probe
tip is in the center of the hopper inlet
tube.
Straighten any crimps in the hoses.
Tighten any loose hoses.
Check the process RTD and tighten if
needed.
Check the heater fuses, and resistance
across each leg of the process heater.
Straighten any crimps in the hoses.
Tighten any loose hoses.
Check that the bed plates are in the
proper position (lined up with the
hoses).
Tighten any loose hoses.
Replace the isolation contactor.
Replace the failed heater solid state
relays (SSRs).
Problem
A1 Process High
Temperature – If the process
temperature exceeds the
process high temperature set-
point, it shuts down the dryer.
Defaults are set to 385°F
(196.1°C) for
20 sec.
A2 Process Temperature
Loop Break – If the process
temperature is outside of the
operator entered deviation,
alarm band (see Process High
Temperature Deviation passive
alarm) and the process tem-
perature is not moving
towards the setpoint at a rate
greater than specified. It shuts
down the dryer. Defaults are
set at 37°F (3°C) over 10 sec.
A3 Process Heater High
Temperature – The snap
switch in the process heater
tube opens due to excessive
temperature.
6
Troubleshooting
Central
When supplied for central
drying applications, these
shut down alarms are not
available.