Repair manual

MT1828
4 --- 1
BURNER
NEW BURNER INSTALLATION
1. Disconnect the power to the oven. Shut off the
main gas valve to the oven.
2. Disconnect the incoming gas line to the oven.
3. Remove the two screws securing the control
box cover. Remove the control box cover.
4. Some ovens have a lower panel below the con-
trol box cover containi ng two fuses. If so, remove
this panel. Disconnect the fuses. Note the way
the fuses are wired. They will need to be rewired
the same way when reconnecting them.
5. Remove the chain guard.
6. Remove the brack et securing the external gas
piping on the back of the oven.
7. Remove the external gas valve assembly at the
elbow on the back of the oven. See FIGURE 2.
8. Open the unio n on the gas stack if applicabl e. This
will disco nnect the burner from the gas stack.
9. Disconnect the burner blower pressure sense
tube from the burner and pressure switch. D is-
card.
10. Disconnect the burner blower wires, igniter wire
and flame sense wire.
11. Loo sen the three 1/4”-20 screws securing the
burner assembly to the burner support. Remove
the burner assembly and all remaini ng gas pipi ng.
12. Remove the red and white wires from the burn-
er valve and ignition control. Install the wires on
theburnervalveofthenewgasstack.
13. Remove the four 1/4”-20 nuts and washers se-
curing the conveyor drive motor bracket to the
control box floor. Remove the drive motor.
14. Remove the ignition control from the control
plate. Install the new ignition control module as
follows:
A.) Mount the new ignition control to the control
plate in place of the old one. The control ter-
minals (not ground) should be oriented up.
B.) Transfer the yel lo w wire from ground on the
old ignition control to ground on the new
igniti o n contro l.
C.) Transfer the wire from THS2 on the old igni-
tion control t o THS2 on the new ignition
control.
D.) Remove the black and yell ow wires con-
nected to L1 on the ol d igniti o n contro l. Re-
place with the black wire provided to con-
nect the transformer to the relay.
NOTE: Refer to the new wiring diagram.
15. Install t he new probes as follows:
NOTE: Refer to FIGURE 1 for correct probe
locations.
A.) Slide the high limit and RTD probes out of
the probe hole. Separate t he two probes.
Set aside the 6” RTD probe.
B.) Install the high limit probe well in the loca-
tion indicated in FIGURE 1. If there is no
hole for the probe well, drill a .38 dia. hole
through the body side and inner liner at the
correct location.
NOTE: Besuretodrilltheholeaslevelaspos-
sible. Deburr the hole and remove the
drill chips from the inside of the control
box. Drill chips will damage wires.
C.) Insert the high limit probe well into the hol e.
Attach the mounting bracket to the body
side with the self drill ing screws provided.
NOTE: It may be helpful to drill a small pilot
hole to start the self drilling screws.
D .) Insert the high limit probe into the well all the
way.
E.) Put a small dab of silicone on the probe well
opening to secure the high limit probe.
F.) Install the new RTD probe into the lo cati on
indicated. Find the leads from the old probe.
Disco nnect the leads from the wiri ng har-
ness. Connect the leads from the new probe
to the harness.
NOTE: The probe bracket may not sit flush
against the oven side due to interference
with the burner support assembly. If so,
use the shim provided.
16. Reinstall the drive motor.
17. Place t he attention plate as close to the exist-
ing rating plate as possible. Drill two 1/8” diam-
eter holes and mount the plate using the 1/ 8”
rivets supplied.
18. Separate the union on the new gas stack and
burner assembly.
19. Slide the new burner assembly into the burner
support until the blower mounting flange is 5.6”
from the back wall of the control box. Be sure
the burner assembly is level and straight.Se-