Duke FWM 6-42 SERIES, Installation And Operation Manual

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Installation and Operation of Product Holding Cabinets
28
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
Location of RTD
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(121.1°C).
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.
NOTE: During normal operation the temperature
may drop below the preset, due to environmental
conditions. When this occurs the actual temperature
will be displayed. This condition will be momentary
and normal operation will resume shortly. If this should
occur frequently or for long periods of time, the affected
unit should not be used and you should contact the
service hotline.
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. 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(± 2.5°C) 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.
Added note
NOTE: During normal operation the temperature may drop
below the preset, due to environmental conditions. When this
occurs the actual temperature will be displayed. This condition
will be momentary and normal operation will resume shortly.
If this should occur frequently or for long periods of time, the
affected unit should not be used and you should contact the
service hotline.