Section 7
Troubleshooting
This table is intended to assist in resolving oven problems by relating
symptoms to their likely cause. The service discussed below is beyond the
scope of most users and should be performed by qualified and trained
personnel.
Isotemp Premium Ovens
7-1
Fisher Scientific
Symptom
Probable Cause
Action
No power
Unit not plugged in or turned on.
Plug in or turn on.
Defective circuit breaker.
Replace circuit breaker.
Oven temperature
erratically high
Defective control thermocouple
Replace control thermocouple
Failure to heat
Set temperature less than actual
temperature
Refer to Operation section
Defective control thermocouple
Replace control thermocouple
Poor heater connections
Tighten connections at terminal
strip and/or heater.
Defective heater element
Check heater resistance on
schematic at back of manual.
Replace heater unless approxi-
mately the same as schematic.
Defective controller
Replace controller
Defective solid state relay
Refer to schematic and replace
relay or safety relay
Temperature Device, disengaged or
defective
Replacement of the
Overtemperature Device is to be
performed by factory authorized
personnel only. Disconnect power
and contact Technical Services.
Alarm LED stays on
and control is higher
that set temperature
Set temperature has been changed
to a value less than the actual tem-
perature minus the alarm limit
Wait for actual temperature to
cool to the set temperature.
Defective controller
Replace controller
Defective control thermocouple
Refer to schematic and replace
relays.
