Shellab SGO5-2 - Manual (Page 12)

12
1/ Check amperage – amperage should be virtually at maximum
rated (data plate) amperage.
2/ do all controller functions work?
3/ Is the Safety Thermostat set high enough?
– for diagnostics,
should be fully clockwise with the OTP light never on.
4/ Has the fuse/circuit breaker blown?
5/ Has timer turned unit off?
Indicated chamber temperature
unstable
1/ ±0.1 may be normal.
2/ For G suffix models: may vary ±2.0 degrees.
3/ For F suffix models: is fan working?
–verify movement of air in
chamber.
4/ Is ambient room temperature radically changing
– either door
opening or room airflow from heaters or air conditioning ? –
stabilize ambient conditions.
5/ This may happen if exhaust stack is 100% open or if power
exhaust is cycling
– adjust stack to at least ¼ closed.
6/ Sensor miss-located, damaged or wires may be damaged -
check mounts for control and OTP sensors, then trace wires or
tubing between sensors and controls.
7/ Calibration sensitivity
– call Customer Service.
8/ High limit set too low – be sure that Safety Thermostat is set
more than 5 degrees over Main Controller set point; check if OTP
pilot is on continuously; turn controller knob completely clockwise
to see if problem solved then follow instructions in section 6.5 for
correct setting.
9/ Electrical noise
– remove nearby sources of RFI including
motors, arcing relays or radio transmitters
10/ 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.
11/ 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.
2/ See if ambient is fluctuating; check for adjacent open doors or
HVAC duct openings
– stabilize ambient conditions.
Display and reference thermometer
don’t match
1/ Calibration error – see section 6.4.
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.
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
Motor doesn't move; F suffix models
1/ If shaft spins freely: check connections to motor and check voltage to
motor.
2/ If shaft rubs or is frozen, relieve binding and retest.
Motor makes noise; F suffix models