Service Procedures And Adjustments; Solid State Temperature Controller Calibration (Sg4D/Sg6D); Calibration Steps; Calibration Tips - Vulcan-Hart SG4D ML-114875 Service Manual

SERVICE PROCEDURES AND ADJUSTMENTS

WARNING: CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TEST OR MEASUREMENTS
WHILE POWER IS APPLIED TO THE MACHINE. EXERCISE EXTREME CAUTION AT ALL TIMES. IF TEST
POINTS ARE NOT EASILY ACCESSIBLE, DISCERN POWER, ATTACH TEST EQUIPMENT AND REAPPLY
POWER TO TEST.
SOLID STATE TEMPERATURE
CONTROLLER CALIBRATION
(SG4D/SG6D)

Calibration Steps

1. Place a thermocouple in the geometric center
of the oven cavity.
2. Set the ON/OFF/OVEN COOL switch to ON.
3. Set the temperature controller dial to 350°F.
Set the power control to 100%.
4. Allow the oven temperature to stabilize
(minimum three heating cycles).
5. Record the temperature at which the Heat
lamp goes ON and comes OFF for at least
two complete heating cycles
6. Calculate the differential by subtracting the
temperature indicated when the lamp goes
out from the temperature indicated when the
lamp comes on.
Differential = Heat lamp ON - Heat lamp OFF.
A. The differential calculated should be less
than 20°F.
1) If the differential is less than 20°F,
the temperature control circuit is
functioning properly. Proceed to step
7.
2) If the differential is more than 20°F,
check the temperature probe as
outlined under Temperature Probe
Test (SG4D/SG6D).
3) If the probe is functioning properly,
then temperature controller is
malfunctioning. Install a replacement
temperature controller and check
calibration.
7. Calculate the average temperature by adding
the temperature indicated when the lamp is
on to the temperature indicated when the
lamp goes out and dividing the answer by 2.
Average Temp = Heat lamp ON + Heat lamp OFF
A. If the average temperature is within 10°F
from the dial setting, the thermostat is properly
calibrated.
B. If the average temperature is more than 10°F
from the dial setting, the thermostat calibration
must be adjusted.
1) Loosen the temperature controller knob
set screw and remove the knob from the
stem.
2) Loosen temperature controller mounting
screws only enough to rotate the control.
a. Place thumb and forefinger on the
b. Center the stem in the opening and
c. Replace knob and retighten set screw.
d. Rotate the knob to the lowest
e. Repeat the average temperature
C. If the above adjustment cannot be obtained,
replace the temperature controller and check
calibration.

Calibration Tips

Allow the oven to cycle at least three times between
adjustments before performing the calculation.
– 20 –
2
head of the mounting screws, apply
pressure and slightly rotate the screw
heads (body of control) in the slot.
Rotate clockwise to increase
temperature and counterclockwise to
decrease.
retighten the temperature controller
mounting screws.
temperature setting then back to
350°F.
calculation in step 7.