Instruction manual

16
Unit will heat up at all
1/ verify that controller is asking for heat by looking for
controller light – if controller light is not on, there is a problem
with the controller
2/check amperage – amperage should be virtually at
maximum rated (data plate) amperage
3/ do all controller functions work?
4/ is the High Limit set high enough? – for diagnostics, should
be fully clockwise with the pilot light never on
5/ has the fuse/circuit breaker blown?
Indicated chamber temperature
unstable
1/ ±0.1 may be normal
2/ is blower motor working? – remove top panel and verify
movement of blower motor in shadow box
3/ is ambient room temperature radically changing – either
door opening or room airflow from heaters or air
conditioning? – stabilize ambient conditions
4/ it may happen if exhaust stack is 100% open or if power
exhaust is cycling – adjust stack to at least ¼ closed
5/ sensor miss-located, damaged or wires may be damaged-
check mounts for control and High Limit sensors, then trace
wires between sensors and controls
6/ calibration sensitivity – call Customer Service
7 / high limit set too low – be sure that High Limit is more than
5 degrees over desired set point; check if High Limit pilot is
on continuously; turn controller knob completely clockwise to
see if problem solved then follow instructions in Section 7.5
for correct setting
8/ electrical noise – remove nearby sources of RFI including
motors, arcing relays or radio transmitters
9/ bad connection on temperature sensor or faulty sensor –
check connectors for continuity and mechanical soundness
while watching display for erratic behavior; check sensor and
wiring for mechanical damage
1 0 / bad connections or faulty solid state relay – check
connectors for mechanical soundness and look for corrosion
around terminals or signs of arcing or other visible
deterioration
Will not maintain set point
1 / assure that set point is at least 5 degrees over ambient
room temperature
2/ see if ambient is fluctuating
Display and actual reference
thermometer don’t match
1/ calibration error – see Jumo users manual
2/ temperature sensor failure – call Customer Service
3/ controller failure – call Customer Service
4/ allow at least two hours to stabilize
5/ verify that reference thermometer is certified
See above
Can't adjust set points or calibration
1/ turn entire unit off and on to reset
2/ if repeatedly happens, call Customer Service
Calibrated at one temperature, but not
at another
This can be a normal condition when operating temperature
varies widely. For maximum accuracy, calibration should be
done at or as close to the set point temperature.