Vulcan-Hart 126743, Service Manual

Page: 19 / 60

FULL SIZE ELECTRIC CONVECTION OVENS - SERVICE PROCEDURES AND ADJUSTMENTS
F25105 (December 2001) Page 19 of 60
A. After the final adjustment is made and the
average temperature is within tolerance,
remove the knob and apply a non-
permanent type sealer around the head of
the set screw.
10. If the above adjustment cannot be obtained:
A. Turn the power switch OFF.
WARNING: DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE MAIN
CIRCUIT BOX. PLACE A TAG ON THE CIRCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
B. Install a replacement thermostat and
check calibration.
SOLID STATE TEMPERATURE
CONTROL TEST
1. Remove the right side panel as outlined under
"COVERS AND PANELS" in "REMOVAL AND
REPLACEMENT OF PARTS".
NOTE: If right side panel is not accessible, this
component can be serviced by removing the control
panel as outlined under "COVERS AND PANELS".
2. Place a thermocouple in the geometric center
of the oven cavity.
NOTE: Oven temperature must be below 450°.
3. Set the temperature control to the maximum
setting.
4. Check machine data plate for correct voltage to
oven. Refer to diagram below for proper
terminal locations and voltages before
checking the control. Use the correct terminals
for the corresponding voltage.
5. Turn the power switch to ON.
6. Check for proper voltage across terminals 8 &
10 (208-240VAC) for power to the control.
A. If correct, proceed to step 7.
B. If incorrect, problem is not with the
temperature control. See
"TROUBLESHOOTING".
7. Check relay voltages on the board:
A. For 208-240VAC controls - check across
terminals 7 & 10 for input to the internal
relay and 6 & 10 for output from the
internal relay.
1) If input voltage to the internal relay is
correct, proceed to step 8. If input
voltage to the internal relay is not
present, problem is not with the
temperature control. See
"TROUBLESHOOTING".
2) If output voltage from the internal
relay is correct proceed to step 8. If
output voltage from the internal relay
is not correct, check temperature
probe as outlined under
"TEMPERATURE PROBE TEST
(SOLID STATE CONTROL)".
8. Set the temperature control to the minimum
setting.
NOTE: Oven temperature must be above 300°F.
9. Check for zero (0) volts AC across terminals 6
& 10 (208-240VAC) for no output from the
internal relay.
A. If correct, temperature control is
functioning properly.
B. If incorrect, check temperature probe as
outlined under "TEMPERATURE PROBE
TEST (SOLID STATE CONTROL)".
1) If temperature probe is ok:
a. Turn the power switch OFF.
WARNING: DISCONNECT THE ELECTRICAL
POWER TO THE MACHINE AT THE MAIN
CIRCUIT BOX. PLACE A TAG ON THE CIRCUIT
BOX INDICATING THE CIRCUIT IS BEING
SERVICED.
b. Replace the temperature control
and check calibration as outlined
under "SOLID STATE
TEMPERATURE CONTROL
CALIBRATION".