Vulcan-Hart ML-044962 Oven User Manual


 
15
THERMOSTATS
The standard oven uses an FDTO-type, modulating thermostat. When first turned on, the flame comes on full
speed, approximately 1
1
/4" to 1
1
/2" tall. As the temperature approaches the set point, the flame slowly reduces
in size. When the temperature is achieved, the flame should be in bypass, approximately
1
/8" tall. The bypass flame
will keep the oven temperature constant unless the door is opened and heat is lost.
When the oven needs to recover heat loss, the thermostat will allow the flame to slowly increase in size until the
temperature is again at the set point. Usually the thermostat does not require calibration, however it may need to
have the bypass flame set at the time of installation. The temperature accuracy of this thermostat is 25°F. For
calibration and/or bypass adjustment, see thermostat calibration section of this manual.
Snorkel and electric ignition ovens use a KX-type snap action thermostat. When first turned on, the flame comes
on full speed. When it achieves the set temperature, it shuts off. When 10°F to 15°F is lost, the thermostat will
come on full speed to recover the heat loss. Due to the fact the thermostat shuts completely off and the oven is
constantly venting heat off through the flue, the thermostat will cycle on and off throughout the cooking process.
The temperature accuracy of the KX thermostat is 15°F to 20°F. If calibration is required, see the calibration section
of this manual.
The thermostat used on griddles is a BJWA modulation type. When first turned on the flame comes on full speed,
approximately
3
/4" to 1" tall. As the temperature approaches the set point, the flame is slowly reducing in size. When
the temperature is achieved, the flame should be in bypass. Bypass flame for griddles should only be big enough
to keep the burner lit all the way around, with little blue dots of flame.
This type of thermostat by design will allow the temperature to creep if the griddle is left idling, with no product
on the griddle, for a minimum of 50°F an hour. Therefore it is imperative that the bypass flame be correct. If the
bypass flame is not correct, the temperature will creep to 100°F to 200°F an hour. Temperature accuracy of the
BJWA thermostat is 25°F. For calibration/bypass adjustments see the calibration section of this manual.
NOTE: Calibrations and/or bypass adjustments require a good working knowledge of the components and system
as well as specific test instruments and should only be performed by authorized service personnel. When checking
calibrations on the BJWA griddle thermostat, it is necessary to begin the procedure when the griddle is cold.
Attempting to calibrate the BJWA griddle thermostat from other than a cold start is extremely difficult, as well as
time consuming, and can cause the temperature to be incorrect at a later time.