TM 5-3895-374-24-2 955-257 8.4  TROUBLESHOOTING GUIDE SYMPTOM CAUSE CORRECTION Power applied, dis- a)   No power applied to a)    Check power wiring play does not light controller. and fusing. and controller does b)   Controller not en- b)    Check if controller not operate. gaged properly in is properly engaged housing. in housing. No  power  to load a)   Open connection to a)    Check load wiring Measurement indi- load. and load fuses. cates temperature b)    Check load  connect- below setpoint. ions. Output indicator is on continuously. Erratic Control a)   Cycle  time  is  too a)    Reduce cycle time. long. When using electro- mechanical relay or contactor, set cycle time at value just below point where load cycling occurs. b)   Proportional band is b)    Increase PB adjust- too narrow. ment until load cyc- ling is eliminated. c)    Rate time is too c)    Increase rate time short. adjustment. Controller operat- a)   System dynamics re- a)    Wait for  system to ing not at setpoint quires more Time. reach setpoint. and calling for b)   Improper sizing of b)    Larger source is 100% power. source to load. required. Display shows Input Thermocouple, RTD or Check thermocouple open. input circuit open. and extension wire in circuits for opens. Inability to tune a)   On controllers with a)    In tuning procedure controller prop- dual 3-mode outputs, outlined previously, erly. resets and rates for the rate and reset both outputs must be adjustments are set set  to  zero before to zero (turned beginning the tuning off). procedure. b)   Cycle time is set too b)    Reduce cycle time. long. ECLIPSE INSTRUMENTATION DIVISION (page 3 - 1129)