Installation and Operation of Product Holding Cabinets
22
TROUBLESHOOTING
There are no user serviceable parts on the Duke
Product Holding Cabinet. If a malfunction occurs,
ensure unit is plugged in then check all switches and
circuit breakers. If the malfunction still exists, contact
your Duke Manufacturing Company authorized service
agent or call 1-800-735-3853.
ELECTRONIC CONTROL FAULT
INDICATIONS
* See 5X1 wiring digram for 5X1 RTD Locations.
The keypad display provides an indication to alert the
operator to failures in the heater circuit. The possible
fault conditions are as follows:
1.
Over-Temperature Fault
- An over-temperature
fault occurs when the control senses that the shelf
temperature is higher than the specified factory
preset temperature for thirty minutes. This occurs
when the power is not removed from the heating
element after the shelf has achieved the preset
temperature. The auxiliary thermostat prevents the
temperature from exceeding safe levels by regulating
the temperature to a maximum of 250°F. If this
occurs, “HI” will appear on the keypad; the affected
unit should not be used until the cause of the fault
is corrected by a qualified service technician.
2.
Under-Temperature Fault
- An under-temperature
fault occurs when the control senses that the shelf
temperature is lower than the specified factory
preset temperature for more than thirty minutes
continuously. This occurs when heating element
circuit opens or the RTD Feedback signal is faulty. If
this occurs, “LO” will appear on the keypad and the
affected unit should not be used until the cause of the
fault is corrected by a qualified service technician.
3.
Sensor Fault
– If it any time during normal operation
“SENS” is displayed on the keypad: discontinue
operation and contact qualified service technician.
TEMPERATURE CHECK PROCEDURE
1. A digital temperature meter that has been calibrated
must be used to get an accurate temperature
reading. Use a thermocouple surface temperature
probe to measure temperatures.
2.
No pans should be in wells during the pre-heat
and temperature check.
Pre-heat the warmer for
30 minutes before taking any temperature readings.
Do not take readings unless the cavity has been
empty for 30 minutes. This will allow the temperature
to stabilize and will prevent false readings.
3. The warmer cavity should be cleaned and empty
before the temperature is checked. Avoid any air
drafts that might flow through the cavity.
4. Locate the surface temperature probe on the bottom
of the first cavity in the geometric center. The first
cavity is the one closest to the control panel (see
figure). Make sure the probe is making good contact
with the surface while taking readings.
5. All temperature controls exhibit a swing in
temperature as the control cycles on and off while
regulating to the set point. The correct calibration
temperature is the average of several readings
taken over a period of 20 minutes after the warmer
has been pre-heated. The average temperature
should be ± 5°F from the set point.
SERVICE HOT-LINE
Check the display for fault messages. Perform the
Temperature Check Procedure in this manual. Make
note of the findings. Please, have this data handy
before calling the Duke troubleshooting Hot Line
listed above. For optimum support, please be near
the suspect units with a cordless phone, if available,
when calling our Technicians.
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