TestEquity FS Series - Troubleshooting Guide

Chapter 4 – Maintenance
Page 4-2 TestEquity FS Series Ovens
Troubleshooting Guide
TEMPERATURE
Temperature too high.
1. Controller set point is too high.
2. Controller failed on – call Customer Service.
Display reads “HI” or “400”+.
1. Probe is unplugged, is broken or wire to sensor is broken – trace
wire from display to probe.
Temperature too low
1. OVERTEMP PROTECTION set too low.
2. TEMPERATURE controller set too low.
3. Unit needs time to recover from door opening – wait for display to
stop changing.
4. Unit not recovered from power failure or being turned off – ovens
will need several hours to warm up and stabilize.
5. Element failure – compare current draw to data plate.
6. Temperature controller failure – call Customer Service.
7. OVERTEMP PROTECTION failure – confirm with front panel
lights that safety thermostat is operating correctly.
Display reads “LO”
1. Bad probe or disconnected – call Customer Service.
2. If ambient temperature is lower than range of unit – compare set
points and ambient temperature to rated specifications.
Oven will not heat over a
temperature that is below set point
1. Confirm that fan is moving and that amperage and voltage match
data plate – check for air movement in chamber.
2. Confirm that set point is set high enough – turn OVERTEMP
PROTECTION all the way clockwise and see if
OVERTEMPERAURE light comes on.
3. Check connections to sensor.
4. Check calibration using a calibrated instrument.
Unit will not heat up at all
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? F
or diagnostics, should be
fully clockwise with the OTP light never on.
4. Has the fuse/circuit breaker blown?
5. Has timer turned unit off?
Will not maintain set point
1. Assure that set point is at least 10 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 – Controller needs re-calibration.
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.
Calibrated at one temperature, but
not at another
1. 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.
Can’t adjust set points or
calibration
1. Turn entire unit off and on to reset.
2. If repeatedly happens, call Customer Service.