Section I Service Checks - Vulcan-Hart E24L Service Manual

SECTION I
SERVICE CHECKS
WARNING: UNPLUG OVEN BEFORE SERVICING.
WARNING: CERTAIN PROCEDURES IN THIS SECTION REQUIRE ELECTRICAL TEST OR
MEASUREMENTS WHILE THE POWER IS APPLIED. EXERCISE EXTREME CAUTION AT
ALL TIMES. IF TEST POINTS ARE NOT EASILY ACCESSIBLE DISCONNECT POWER,
ATTACH TEST EQUIPMENT AND REAPPLY POWER TO TEST.
THERMOSTAT CALIBRATION CHECK
If the product recipe catic for 350 degrees for 30 minutes and at the end of the cooking time with thermostat set
at 350 degrees your product is consistantly under or over cooked the oven thermostat may be out of calibration
and should be checked and adjusted if required.
If calibration is a suspected problem perform steps 1-6 below to determine the center average heating
temperature the oven and refer to Section II of the manual if thermostat calibration is required.
1. Turn oven off, allow it to cool then open the oven door.
2. Place oven rack in center oven position.
3. Place a calibrated potentiometer thermocouple in the oven cavity centered on the oven rack.
4. Turn oven on and set oven temperature to 350 degrees F.
5. Allow the oven to cycle 3 complete times.
6. After the third cycling period, record cycle at highest point, record cycle at lowest point.
Example: High point 360 degrees F. (Burner cycle off temperature)
Low point 340 degrees F. (Burner cycle on temperature)
Differential: If the differential exceeds 25 degrees F. then thermostat should be replaced.
To calculate this example or any other high/low point center oven average follow the method below.
Add the highest and lowest cycle values together then divide this value by 2.
Example: 360 + 340 = 700 then 700 divided by 2 = 350. The calibration set point will be
350 degrees F.
INFINITE SWITCH CHECK
1. With power on using a volt meter check for 120 Volts AC input across H1 and H2 terminals.
2. H2 has 120V AC Output, but it is not a constant output. The output will cycle on and off as long
as the input to the switch is present. The timing of this output is determined by the switch
setting. By timing the switch cycles at various settings you can determine if the switch is
properly working. See the chart below.
DIAL SETTING PERCENT ON TIME
Hi
Med.
Low
Med. Low
Very Low
NOTE: The P terminal is a neutral leg of the switch. When the control is turned from the off position to any
other position P is making contact with L1. L1 is a neutral connection. L2 is a 120V AC input.
H1 is used as a neutral point for testing of load control output.
SECONDS ON
100
48
37
28
7
SECONDS OFF
ALL 0
15 15
8 14
7 24
3 33
4