Red Lion TCU User Manual

Page 87

Problems

Possible Cause

Remedies

“OLOL” IN DISPLAY

1. Temperature exceeds range of input probe.
2. Excessive positive probe temperature.
3. Loss of set-up parameters.

1. Change to input sensor with a higher temperature range.
2. Reduce temperature.
3. Check set-up.

“ULUL” IN DISPLAY

1. Temperature below range of input probe.
2. Excessive negative probe temperature.
3. Loss of set-up parameters.

1. Change to input sensor with lower bottom range.
2. Increase temperature.
3. Check set-up parameters.

“SHrt” IN DISPLAY

1. RTD probe shorted.

1. Check wiring.
2. Replace RTD probe.

“VALV” IN DISPLAY
Valve Fail Alarm

1. Valve or valve motor jammed.
2. Loss of power to valve motor.
3. Slidewire feedback signal lost.

1. Check valve or valve motor for operation.
2. Check power to valve motor.
3. Increase valve fail time.

“SLId” IN DISPLAY

1. Slidewire feedback signal lost.

1. Check slidewire feedback signal.

T E M P E R A T U R E S L U G G I S H O R
NOT STABLE

1. Incorrect PID values.
2. Heater undersize.
3. Improper probe location.

1. See PID Control.
2. Increase heating power.
3. Evaluate probe location.

EXCESSIVE VALVE ACTIVITY OR
HUNTING

1. Insufficient valve control deadband.
2. Insufficient output dampening.
3. Incorrect PID values.
4. Valve update time too short.

1. Increase valve deadband.
2. Increase output dampening.
3. See PID Control.
4. Increase valve update time.

OUTPUTS NOT WORKING

1. Output module not installed.
2. Improperly wired.
3. Incorrect output module.
4. Defective output module.

1. Install output module.
2. Check wiring.
3. Check output module.
4. Check or replace output module.

LINEAR DC OUTPUT
NOT WORKING

1. Improper load resistance.
2. Incorrect programming or scaling.
3. Connections reversed.
4. DC voltage source in loop (4 to 20 mA only).

1. Check load resistance.
2. Check programming.
3. Check connections.
4. This is an active loop. Remove all DC voltage sources (4 to 20 mA only).

CONTROLLER LOCKS UP
OR RESETS

1. Noise spikes entering controller due to load

switching transients.

2. Defective controller.

1. Use RC snubber across the load.

a. Use Triac output modules whenever possible.
b. Use separate AC feed line to controller.
c. Locate controller & signal lines away from noise producing

mechanisms (solenoids, transformers, etc).

2. Replace Unit.