Alto-Shaam 1000-TH-II - Manual (Page 19)

PG . 18 TH-II INSTALLATION / OPERATION / SERVICE MANUAL
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 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 thermostat 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.
THERMOSTAT CALIBRATION
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.
Following temperature stabilization, the center of the
thermal swing of the air temperature 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 appreciably
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 polish or equivalent is acceptable.)
S E R V I C E
D A N G E R
DISCONNECT UNIT FROM
POWER SOURCE BEFORE
CLEANING OR SERVICING.