Shellab SMO38HP-2 - Manual (Page 14)

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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
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
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
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
Motor doesn't move
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
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.