AERCO BMK 1.5 LN June 2010 - Manual (Page 54)

MAINTENANCE
7-4
Figure 7-4
Burner Assembly Mounting Details
4. Remove the two (2) screws securing the
flame detector to the plate. The flame
detector is secured to the burner plate with
one (1) #10-32 screw and one (1) #8-32
screw.
5. Remove the flame detector and gasket from
the burner plate.
6. Disconnect the cable from the ignitor-
injector.
7. Using a 7/16” open-end wrench, disconnect
the compression nut securing the gas
injector tube of the ignitor-injector to the
elbow of the staged ignition assembly (see
Figure 7-2). Disconnect the staged ignition
assembly from the ignitor-injector.
8. Next, loosen and remove the ignitor-injector
from the burner plate using a 1" open-end
wrench.
9. Disconnect the unit wiring harness
connectors from the air/fuel valve and
blower motor.
10. Disconnect the wire leads connected to the
blower proof switch and blocked inlet switch
(Figures 7-4 & 7-5).
11. Remove the 10-32 x 1/2" long. grounding
screw from the burner plate (Figures 7-4 and
7-5).
12. Disconnect the gas train from the air/fuel
valve by removing the four (4) 1/2” bolts and
nuts (Figure 7-4).
13. Disconnect the flex hose from the air/fuel
valve by loosening the hose clamp.
14. Remove the four (4) 5/16-18 hex head
screws securing the blower to the burner
plate (Figure 7-5).
15. Remove the blower and air/fuel valve from
the burner plate by lifting straight up. Also,
remove the blower gasket.
16. Remove the eight (8) 3/8-16 nuts from the
burner flange (Figure 7-4) using a 9/16”
wrench.
NOTE
The burner assembly is heavy, weighing
approximately 25 pounds.
17. Remove the burner assembly from burner
flange by pulling straight up.
18. Remove and replace the two (2) burner
gaskets.
NOTE
During reassembly, apply high-tempera-
ture, anti-seize lubricant to the threads of
the ignitor-injector and grounding screw.
Also, ensure that the ignitor-injector is
properly positioned as indicated in Figure
7-3. Torque the ignitor-injector to 15 ft-lbs.
19. Beginning with the burner assembly
removed in step 17, reinstall all the
components in the reverse order that they
were removed.
20. Ensure that the ignitor-injector and flame
detector cutouts in the burner plate are
properly aligned with the heat exchanger top
flange.