15
Product Holding Unit
Restaurant Equipment Manual
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 shelf 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 the first cavity in the geometric center.
The first cavity is the one closest to the control panel (see Figure 3). 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.
Troubleshooting
There are no user serviceable parts on the Duke Product Holding Unit. 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