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PRODUCT HOLDING CABINET
RESTAURANT
EQUIPMENT
MANUAL
REVISION:
August 18, 2005
U.S. Patent 6175099, 6262394
Other U.S. and Foreign Patents Pending
DUKE MANUFACTURING CO.
TOLL FREE 800-735-DUKE (3853)
314-231-1130
Troubleshooting
Electronic Control Fault Indications
The Service Light is located on the front of the control next to the heat light (see Figure 3). It provides an
indication to alert the operator to failures in the heater circuit. When a Service Light is on, the affected unit
should not be used until the cause of the fault is corrected by a qualified service technician. The fault
conditions that could cause the control to turn the service light on 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. This occurs when the power is
not removed from the heating element after the shelf
has achieved the preset temperature, causing the
control to turn on the service light. The auxiliary
thermostat prevents the temperature from exceeding
safe levels by regulating the temperature to a
maximum of 250
°
F.
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 30 minutes continuously.
This occurs when heating element circuit opens or
the RTD Feedback signal is faulty, causing the
control to turn on the service light.
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 any cavity in the geometric center. 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
±
15
°
F from the set
point.
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.
Figure 3
