Despatch LAC2-12-6 - Manual (Page 35)

LAC Series Oven Owner’s Manual T ROUBLESHOOTING
Version 106 35
Copyright © 2011 by Despatch Industries.
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Table 3. Troubleshooting Oven Symptoms.
Symptom Possible Cause Next Step
Failure to heat
or heats to
only 35-50
degrees C
No power Check power source and/or oven and wall fuses
Broken or frayed cord Replace with new cord
Burned out heater Replace heater (see Warranty Section 8.1)
Protocol™ malfunction Replace controller
Loose wire connections
Disconnect power and check connections behind control
panel
Heater relay failure Replace circuit board
Door switch failure Replace door switch
Slow heat-up
Improperly loaded Reduce load or redistribute load in chamber
Low line voltage
Supply sufficient power and proper connections. Check
for circuit overload
Heating element(s) are
burned out Replace burned out element (see Warranty Section 8.1)
240 volt oven is connected
to a 208V line Raise line voltage to a 240 volt line or modify oven for
208V operation (consult factory)
Fan motor failure Replace fan motor
Frequent
heater
element out
Harmful fumes generated
by load Increase vent opening or discontinue process
Spillage or splattering of
material on heater
elements Disconnect power and clean oven chamber and elements
Overheating oven Check the Hi-limit
Erratic or
inaccurate
temperature
Protocol™ Plus Controller
malfunction Replace Protocol™ Plus Controller
Improper tuning
parameters Check tuning parameters
Protocol™ Plus Controller
miscalibration Recalibrate Protocol™ Plus Controller (See Protocol Plus
Owner’s Manual, sections on Calibration)
Hi-limit setting Hi-limit should be 10-25°C higher than setpoint
Improper offset Check zone calibration
Excess
surface or
door
temperature
Door seal deterioration Replace door seal
Improper
airflow
Fan motor failure Replace fan motor
Fan wheel seated too low
on fan shaft Adjust fan wheel for 3/16" clearance between wheel and
inlet ring
Unbalanced fan wheel Replace fan wheel
Excessive
vibration
Dirty fan wheel Clean fan
Unbalanced fan wheel Replace fan wheel
Oven will not
control at
setpoint
Hi-limit set too low Set the Hi-limit higher
Protocol malfunction Replace control
SSR malfunction Replace SSR and/or check control output voltage
Air friction of recirculation
fan Open exhaust air vent. Unit will not control below
minimum operating temperature with vent closed
Heater does
not shut down
until temp.
reaches the
Hi-limit setting
Protocol malfunction
Replace Protocol
SSR malfunction Replace SSR