Aerco Benchmark BMK 750 User Manual page 50

Benchmark 750-3000 Boiler Operation, Service, Maintenance Guide - KOREA
SECTION 4 – MAINTENANCE
BMK 1500-3000 Burner Inspection Instructions
10. You must either rig a support for the blower to hold it in place or remove the blower from
the unit and set it aside for later reassembly.
11. Remove the eight (8) 3/8-16 nuts, using a 9/16" wrench, attaching the blower plenum to the
burner. See Figure 4-5a & 4-5b (BMK 1500/2000) or Figures 4-5c & 4-5d (BMK
2500/3000).
12. Remove the blower plenum from between the blower and the burner and set it aside for
later reassembly. The O
plenum flange.
13. Remove the burner by pulling straight up. Note, this assembly weighs approximately 65
lbs. (29.5 kg).
14. Remove and replace the burner gasket(s) (see Figure 4-6, below).
IMPORTANT!
ALL THREE gaskets provided for maintenance MUST be installed during this procedure, as
shown in Figure 4-6, even if there is only one existing gasket being replaced. Note that the
LOWER RELEASE GASKET has tabs, which the others do not.
NOTE:
During reassembly, apply a light coating of high-temperature, anti-seize lubricant to the
threads of the igniter-injector and grounding screw. Also, ensure that the igniter-injector is
properly positioned as indicated in Figure 4-3b or Figure 4-3c. Torque the igniter-injector to
14 - 15 ft-lbs. (19.0 - 20.3 Nm).
UPPER RELEASE GASKET
MIDDLE BURNER GASKET
LOWER RELEASE GASKET
(Note
four tabs around its periphery)
Burner
installed in
heat
exchanger
assy.
Figure 4-6: Bare Burner and Replacement Gaskets Location
15. Beginning with the burner assembly, reinstall all the components in the reverse order that
they were removed. When reinstalling the blower plenum (removed in step 11), tighten the
3/8-16 nuts using a typical torque pattern (for example, loosely tighten one nut, then
loosely tighten a second nut on the opposite side, a third at 90 degrees to the first two, and
a fourth opposite the third, and then repeat this pattern with the remaining four nuts.
Repeat the entire pattern a second time to partially tighten all eight nuts, and then repeat a
third time until all eight nuts are fully torqued to
16. Ensure that the igniter-injector and flame detector cutouts in the burner plate are properly
aligned with the heat exchanger top flange.
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sensor and flame observation port remain assembled to the
2
AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913
Ph.: 800-526-0288
35 ft. lbs. (47.5 Nm).
OMM-0128_0C
GF-206-K