Troubleshooting, Possible problems and suggested solutions, Table 2. troubleshooting grid – Despatch RAD Series User Manual
Page 32

T
ROUBLESHOOTING
RAD Oven Series Owner
’s Manual
32
Version 1
Copyright © 2012 by Despatch Industries.
All rights reserved. No part of the contents of this manual may be reproduced, copied or transmitted in any form or by any 
means including graphic, electronic, or mechanical methods or photocopying, recording, or information storage and 
retrieval systems without the written permission of Despatch Industries, unless for purchaser's personal use. 
7.
Troubleshooting
7.1. Possible Problems and Suggested Solutions
Equipment which operates for long periods of time may develop problems.
problems and suggested solutions. If you have a problem not listed and do not know what to do, 
contact Despatch Industries at our toll free Help Line 800-473-7373. 
Table 2. Troubleshooting grid. 
Difficulty 
Probable Cause
Suggested Remedy
Failure to heat or 
heats up to only 35-
50ºC 
No power
Check power source and/or oven and wall 
fuses 
Burned out heater
Replace heater (see warranty, Section 8.1)
Protocol 3 controller 
malfunction 
Replace controller
Loose wire connections
Disconnect power and check connections be-
hind control panel 
Heater relay failure
Replace heater contactor or SCR
Door switch failure (if 
installed) 
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 heater (see warranty, Section 8.1) 
 
Fan motor failure
Replace fan motor
Frequent heater 
element burnout 
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. 
Take measures to prevent splattering. 
Overheating oven
Check the High Limit
Erratic temperature 
or 
inaccurate 
temperature 
Protocol 3 controller 
malfunction 
Replace controller
Improper tuning 
parameters 
Check tuning parameters
Protocol 3 controller 
miscalibration 
Recalibrate controller (see Protocol 3 
Controller Owner’s Manual for further 
instruction manual). 
High Limit setting
High Limit should be 10-25ºC higher than 
setpoint. 
Defective SCR
Replace SCR
Improper offset
Check zone calibration
 
Excess surface or 
door temperature 
Door seal deterioration
Replace door seal.
 
Improper airflow 
Fan motor failure
Replace fan motor
