Shel lab FX14-2 Installation And Operational Manual page 12

Will not maintain set point
Display and reference thermometer don't
match
Can't adjust set points or calibration
Calibrated at one temperature, but not
at another
Motor doesn't move
Motor makes noise
Door not sealing
3/ Is ambient room temperature radically changing – either door
opening or room airflow from heaters or air conditioning ? – stabilize
ambient conditions.
4/ This 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 OTP sensors, then trace wires or tubing between
sensors and controls.
6/ Calibration sensitivity – call Customer Service.
7/ 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.
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.
10/ 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.
11/ If set point is below 60 degrees, temperature can be unstable. See
unit specifications for individual ranges.
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.
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.
1/ Turn entire unit off and on to reset.
2/ If repeatedly happens, call Customer Service.
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
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.
1) Make sure that the fan or blower wheel is not contacting its
housing. Adjust the motor mounting bracket position to re-center
the fan or blower wheel, if necessary.
2) Check the fan or blower wheel for damage or out of balance
condition. Replace the fan or blower wheel if it is damaged or out
of balance.
3) Turn the motor shaft to make sure that it spins freely. If it binds
or the bearings make a rubbing or scrapping sound then replace
the motor.
1/ Adjust hinge blocks or twist the door.
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