AERCO BMK 6000 Dual Fuel - Manual (Page 109)

Benchmark 6000 DF Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
OMM-0096_0B AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 Page 109 of 219
GF-141
Ph.: 800-526-0288
03/21/2014
7.8.1 Rear Refractory Removal & Replacement
Complete the following steps to access and replace the rear refractory:
Rear Refractory Replacement Procedure
1. Turn off gas and electrical power to the unit. In addition, turn off any other units sharing the
exhaust flue.
2. Disconnect the flue from the exhaust manifold of the boiler being serviced and remove flue
sections up to the top of the unit enclosure.
3. Remove the left-rear panel, which is held in place by 2 spring latches and 7/16” bolts,
inside the panel on the top rail and bottom lip. See Figure 7-6.
4. With the panels removed, the rear plate of the combustion chamber can be accessed as
shown in Figure 7-7.
The surfaces of the heat exchanger may be hot. Allow the unit to cool
sufficiently before proceeding to the next step.
5. Remove the O
2
sensor and the 1/4” stainless steel tube from the rear plate.
6. Disconnect the wires from the thermal switch on the rear plate.
7. Remove all of the bolts from the rear plate, EXCEPT for the one at the top of the plate.
8. Loosen (but DO NOT remove) the top bolt and slide a thin metal object (such as a
hacksaw blade) between the rear plate and the fiber material of the rear refractory to
separate the material from the plate.
The rear plate weighs approximately 40 pounds. It is therefore
recommended that 2 people be used when removing the plate.
9. Remove the top bolt from the plate and remove it from the unit.
10. Refer to Figure 7-8 and note the position of the rear refractory. Prior to refractory removal,
mark as necessary using a permanent marker or tape.
11. Gently pull on the two opposing metal tabs located on the outer edge of the fiber blanket,
then alternately pull on the other two opposing tabs. Continue this process until the fiber
refractory package can be removed from the combustion chamber.
12. Place the fiber insulation package, metal face down, in a safe location to avoid damage.
13. The combustion chamber can now be viewed and inspected with a full view of the Burner
assembly and rear tubesheet.
14. Following inspection, reinstall the components in the reverse order that they were
removed.
CAUTION
CAUTION