Thermcraft XOV-21-21-19.5-1A-2-SL - Manual (Page 12)

Indicated chamber temperature
unstable
1/ ±0.1 may be normal.
3/ For Forced air 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
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.