Vulcan-Hart VC6ES Service Procedures and Adjustments, Solid State Temperature Control Calibration

FULL SIZE ELECTRIC CONVECTION OVENS - SERVICE PROCEDURES AND ADJUSTMENTS

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, DISCONNECT POWER, ATTACH TEST EQUIPMENT AND REAPPLY POWER TO TEST.

SOLID STATE TEMPERATURE

CONTROL CALIBRATION

1.Place a thermocouple in the geometric center of the oven cavity.

2.Set the power switch to ON.

3.Set the temperature control dial to 350 °F.

4.Allow the oven temperature to stabilize (normally 3 cycles).

5.Record the temperature at which the Heat lamp goes OFF and comes ON 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 OFF Heat lamp ON Example: 360￿(lamp off) ￿340￿(lamp on) ￿20￿

A.The differential calculated should be less than 20 °F.

1)If the differential is 20 °F or less, the temperature control circuit is functioning properly.

a.Proceed to step 7.

2)If the differential is more than 20 °F:

a.Check the temperature probe as outlined under "TEMPERATURE PROBE TEST (SOLID STATE CONTROL)".

b.If the probe is functioning properly then temperature control is malfunctioning.

a)Install a replacement temperature control and check calibration.

7.Calculate the average temperature by adding the temperature indicated when the lamp goes out to the temperature indicated when the lamp comes on and dividing this answer by 2.

[Temp. (lamp off) ￿Temp. (lamp on)] ÷ 2 ￿Average Temp.

Example: 360￿￿340￿÷ 2 ￿350￿

A.If the average temperature is 10 °F or less, 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 control knob set screw and remove the knob from the stem.

2)Loosen temperature control mounting screws only enough to rotate the control.

a.Place thumb and forefinger on the 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.

b.Center the stem in the opening and re-tighten the temperature control mounting screws.

c.Replace knob and re-tighten set screw .

Page 17 of 60 F25105 (December 2001)