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Troubleshooting l 6-7
Shut Down Alarms
Problem
A8 Process Blower Pressure
– If the process blower pres-
sure switch opens (loss of
pressure), it shuts down the
dryer.
A24 Regen Blower Pressure
– The regeneration blower
pressure switch opens (loss of
pressure) and the regeneration
heater shuts down.
NOTE: The system may
index one more time
after the alarm, then
stop indexing.
A36 Control
Communications Watchdog -
The display board has lost
communications
with the control board.
A38 Phase Error (Phase
Option, STD, on MDC's) -
One of the three power wires
is connected wrong.
A39 EEProm Write Error
Possible cause
The tubing going to the pressure switch
is cut or has come loose.
The process blower overload has tripped.
The blower motor starter has failed
The tubing going to the pressure switch
is cut or has come loose.
The blower motor relay has failed.
Plugs on wire harness between the
display and control boards are loose.
Display board or Communications
boards have failed.
One of the three power wires are out of
phase.
Phase Detector Board has failed.
Internal Control board problem.
Solution
Check the tubing for cracks and make
sure it is secure on the fittings.
Check the process blower overload. If it
is tripped, check the process blower to
make sure its not locked. Make sure the
overload is set slightly above the full
load current shown on the motor name-
plate. Refer to your wiring diagram for
proper settings.
Check the process blower motor starter.
Check the tubing for cracks and make
sure it is secure on the fittings.
Check the regeneration blower motor
relay.
Make sure plugs are tight on board
connections.
Replace the boards.
Switch the position of two of the incom-
ing lead power wires at the dryer.
Replace the Phase Detection Board.
Replace the Control board.
✐
6
Troubleshooting