1)
If temperature probe is functioning
properly and the temperature controller
failed the test in 8c above, replace the
temperature control and check for
calibration as outlined under Solid
State Temperature Controller
Calibration (SG4D/SG6D).
SOLID STATE TEMPERATURE
CONTROL CALIBRATION (SG4D/
SG6D)
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.
Before attempting any calibration, see Section 8C of
SOLID STATE TEMPERATURE CONTROLLER
TEST (SG4D/SG6D) on previous page.
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% (10).
4.
Allow the oven temperature to stabilize
(minimum three heating cycles).
5.
Record the temperature at which the Heat lamp
comes ON (heating starts) and goes OFF
(heating stops). This is the control differential.
Heat lamp OFF temp - Heat lamp ON temp =
Control Differential.
6.
The nominal control differential should be less
than 20°F.
A.
If the control differential is less than 20°F,
the temperature control circuit is functioning
properly. Proceed to step 7.
B.
If the control differential is more than 20°F,
check the temperature probe as outlined
under Temperature Probe Test (SG4D/
SG6D).
C.
If the control differential is more than 20°F
and the probe passes its' test parameters,
then temperature controller is
malfunctioning. Install a new temperature
controller and run calibration steps again.
7.
Calculate the average oven temperature by
adding the actual minimum temperature to the
actual maximum temperature and dividing by 2.
EXAMPLE:
Oven set to 350°F.
Actual minimum oven temperature = 335°F
Control cuts on at 334°F
Actual maximum oven temperature = 347°F
Control cuts off at 340°F
335 + 347 = 682
682/ 2 = 341 (the control is 9°F out of calibration)
340 - 334 = 6°F Control Differential
347 - 335 = 12°F Oven Temperature Differential
A.
If the average oven temperature is /-
5°F from the dial setting, no calibration is
necessary.
B.
If the average oven temperature is not within
+/- 5°F, calibration is recommended.
8.
Loosen the set screw on the temperature
controller and carefully remove the knob from the
shaft, without rotating the shaft. This will expose
the calibration adjustment control access hole in
the front panel.
9.
Monitor the internal oven temperature and
determine at what temperature the control should
cut on to give you the required minimum
temperature (Example: 350-341=9; 334+9=341.
341°F is the temperature at which you would wish
the controller to cut on).
10. After allowing the oven to operate through
several cycles (minimum 3 cycles), monitor the
temperature as it falls to the desired "cuts on"
point. Using a small screw driver, adjust the
calibration adjustment until the controller cuts on
at the desired "cuts on" temperature.
11. The calibration control is adjusted clockwise in
order to increase the set temperature and
counter clockwise to decrease the set
temperature.
12. The controller has only +/- 25°F of adjustment.
1/4 turn of the calibration adjustment represents
approximately 20°F shift in calibration.
SG4 & SG6 Series Full Size Gas Convection Ovens - SERVICE PROCEDURES AND ADJUSTMENTS
Page 27 of 56
F35626 Rev. B (1118)
