Shel lab SMO5CR-2, Installation And Operational Manual, Page: 15 / 20

15
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.
MECHANICAL
Door not sealing
1/ check physical condition of gasket
2/ assure that gasket is in original location