Electric Oven Service Manual

2. Check the input voltage on terminals L1
& L2 (208-240 VAC) and the DC voltage
input on terminals 2 & 5 (0.1-10 VDC).
3. If no voltage is present, inspect the wire
harness for damage or shorts (page 45).
4. If wire harness is intact and undamaged,
the BMSC is damaged or defective and
must be replaced (page A-8 = lower, A-12 =
upper).
Accessing Parameters
WARNING: DO NOT perform this
procedure unless instructed by
TurboChef.Changing the parameters to
other than those preset by TurboChef can
damage critical oven components.
1. Open the right or left end bell depending
on which BMSC requires testing
(page 1, A-1).
2. Locate the BMSC (page A-1).
3. Press the
MODE key.
4. Use the keys to navigate the parameters.
5. Press the
MODE key to access the parameter
shown on the BMSC display.
6. Use the keys to manipulate the
parameter.
7. Press the
MODE key to return to the
parameter selection.
8. Repeat steps 4-7 to manipulate other
parameters as needed.
The Burner System
This section contains information about and
testing procedures for the following
components:
- Air Pressure Switch
- Burner Transformer
- Combustion Blower
- Modulating Gas Valve
- Ignition Module
Air Pressure Switch
The air pressure switch contacts close when a
0.1in WC (2.54mm WC) differential exists
between the two ports. The air pressure switch
has one negative port and one positive. The air
tube from the combustion blower is attached to
the positive port. The air tube must not be dam-
aged in any way (cracked or split). The connec-
tion must be tight at the combustion blower and
the switch itself to ensure proper operation of the
air pressure switch.
Testing Procedure
1. Attach a digital manometer to the air tube
coming from the combustion blower.
2. A reading above 0.1in WC (2.54mm WC)
is required to close the contacts. If the
reading is below 0.1in WC (2.54mm WC),
check the combustion blower operation.
Burner Transformer
The burner transformer converts incoming line
voltage to 24 VAC output.
Testing Procedure
1. Disconnect line voltage to the burner
transformer.
2. Remove the burner transformer lead wires.
3. Check the resistance of the primary and
secondary windings, refer to Figure 33, to
determine if the transformer is functioning
properly.
4. Set up the wire configuration for 208 or 240:
- 208 VAC installation: connect wire B
(blue) to wire C (blue). Figure 32, below, is
configured for 208 VAC operation.
- 240 VAC installation: connect wire A (red)
to wire C (blue).
26 OVEN SYSTEMS
B
C
A
Figure 32: Burner Transformer Wires