Benchmark 6000 Boiler Installation, Operation & Maintenance Manual
CHAPTER 7 – MAINTENANCE
Page
102
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210
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, NY 10913
OMM-0086_0D
03/20/14
Ph.: 800-526-0288
GF-133
THE HEAT EXCHANGER INSULATION UTILIZES CERAMIC FIBER
MATERIAL. WEAR A FITTED NIOSH-APPROVED PARTICULATE
RESPIRATOR (3M N95 OR EQUIV.) WHEN SERVICING THE HEAT
EXCHANGER AND BURNER ASSEMBLIES. AT HIGH TEMPERATURES,
CERAMIC FIBERS CAN BE CONVERTED TO CRYSTALINE SILICA
FIBERS WHICH HAVE BEEN IDENTIFIED AS CARCINOGENIC WHEN
INHALED.
7.8 REFRACTORY REMOVAL & REPLACEMENT
Low mass, fiber-based material insulates the front and rear end plates of the combustion
chamber. This material has very low thermal conductivity and is not susceptible to thermal shock
conditions that cause failures of hard-faced refractory materials.
In the event that access to the unit’s combustion chamber is required, the preferred method is to
remove the rear refractory first, since it requires fewer and less complicated procedural steps.
However, if the front refractory is removed first, the complete Burner assembly, blower assembly
and air/fuel valve assembly must be removed to access the refractory material.
The procedures for removal of the rear refractory and front refractory materials are provided in
sections 7.8.1 and 7.8.2, respectively.
7.8.1 Rear Refractory Removal & Replacement
In order to access and replace the rear refractory, the following steps must be performed:
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.
NOTE
At the top, the left-rear and right-rear covers are affixed to the left
and right top rails by nuts. At the bottom, each rear cover is affixed
to the base with one nut each. Access the nuts for removal through
the side panel, as shown in Figure 7-6.
3. Remove the right-rear panel which is held in place by 7/16” nuts on the top rail and inside
the bottom lip. Also, open the 2 spring latches. See Figure 7-6.
4. With the panel 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.
WARNING
CAUTION
