Alto-Shaam 750-CTUS - Manual (Page 13)

12.
√
S E R V I C E
THERMOSTAT & PILOT LIGHT SEQUENCE
Whenever the thermostat is turned “ON,” the
indicator light will indicate the power ON/OFF
condition of the heating cable, and consequently,
the cycling of the cabinet as it maintains the dialed
cavity temperature. If this light does not illuminate
after normal start-up, the main power source,
thermostat, and/or indicator light must be checked.
If the warming cabinet does not hold the temperature
as dialed, the calibration of the thermostat must be
checked. If the warming cabinet fails to heat or heats
continuously with the thermostat “OFF,” the thermo-
stat must be initially checked for proper operation.
If these items are checked and found to be in order,
a continuity and resistance check of the heating cable
should be made. SEE CIRCUIT DIAGRAM.
The thermostat is precision calibrated at the factory.
Normally, no adjustment or recalibration is necessary
unless the thermostat has been mishandled in transit,
changed or abused while in service. A thermostat
with a sensing bulb operates on hydraulic pressure,
consequently, any bending of the bulb results in a
change in its volume, and alters the accuracy of the
thermostat calibration.
A thermostat should be checked or recalibrated by
placing a quality, thermal indicator at the center of
an empty holding cavity. DO NOT CALIBRATE
WITH ANY FOOD PRODUCT IN THE CABINET.
The thermostat should be set, and should be allowed
to stabilize at that setting for a minimum of one
hour. The center of the thermal swing of the air tem-
perature within the cabinet should approximately
coincide with the thermostat setting.
If calibration is necessary, the calibration screw
should be adjusted with great care. The calibration
screw of the thermostat is located in the thermostat
dial shaft. With the shaft held stationary, a minute,
clockwise motion of the calibration screw apprecia-
bly lowers the thermostat setting. A reverse, or
counter-clockwise motion appreciably raises the
thermostat setting. After achieving the desired
cycling of the thermostat, the calibration screw must
be sealed. Place a few drops of enamel sealant
directly on the calibration screw.
(Red nail p o lish o r eq uivalent is accep table.)
THERMOSTAT & INDICATOR LIGHT SEQUENCE THERMOSTAT CALIBRATION
C A U T I O N
THIS SECTION IS PROVIDED FOR THE ASSISTANCE
OF QUALIFIED SERVICE TECHNICIANS ONLY AND
IS NOT INTENDED FOR USE BY UNTRAINED OR
UNAUTHORIZED SERVICE PERSONNEL.